MONDAY, JANUARY 27, 1986

1 P.M.

        In the grandstands at Kennedy Space Center, the crowd waits for the countdown to tick along.  It is a brisk and clear Monday, in the 50s, and the sun is shining on friends and relatives of the space shuttle Challenger's seven crew members.

        Just hours away from Florida, though, glacial winds are coating the country with ice.  Citrus growers on the Space Coast, who often pause in their groves to watch the shuttle roar above their treetops, are stopping now to hear the National Weather Service bulletin:

        ''Temperatures may approach all-time record lows...  This could be a major freeze on a par with the Christmas 1983 freeze and January freeze of last year.  All possible precautions should be taken...''

        Across the state, citrus workers scramble, hauling out fuel-oil heaters and preparing to move them into the fields.  They flood their groves with warm groundwater.  They bank dirt around young trees.  A third freeze will strike the deathblow to thousands of citrus acres.

        The fruit trees surrounding Kennedy Space Center, growing on the northern edge of the Citrus Belt, are especially vulnerable.  The last freeze killed 840 acres on federal land just north of the space shuttle launch complex.

        On the northernmost part of the launch complex, Challenger sits poised above the flatlands.  No shelters or walls surround it on pad 39B.  Nothing will block the coming arctic winds.

        Inside the crew cabin, the seven astronauts are strapped into place, eager to go.  After five one-day delays, this looks like the day NASA will rocket a teacher into space.

        Along with the hundreds of other spectators, Christa McAuliffe's parents are waiting in the grandstands near the Launch Control Center.  Her husband and two children are with the immediate families of other shuttle crew members, watching from an office on the fourth floor inside the control center.

        They are confident, and they are proud of Christa, who was picked from among 11,400 teacher applicants.  They believe in her mission to humanize space.

        But everyone grows a little tired from sustaining the thrill through so many delays.  The third-graders from young Scott McAuliffe's class are fidgety while they wait outside at KSC.  The students visiting from the Concord, N.H., high school are bursting with tension.  And, back at Concord High, where McAuliffe teaches social studies, the 1,200 students are ready with party hats and noisemakers.

        Then a bolt sticks on the shuttle's hatch.

        The closeout crew can't close the door.  They decide to drill it out.  But they can't find a drill.  Then the drill they manage to find fails.  Then a second drill can't complete the job.  With a hacksaw, they finally cut the bolt off.

        Just as it comes off, though, the winds start up.  They whip to 30 mph -- too dangerous in case the shuttle has to make an emergency landing before entering orbit.  Shortly before 1 p.m., Mission Control tells the crew to climb down.  They'll try again tomorrow -- Tuesday morning.

        Drained from almost five hours of waiting inside the shuttle, stiff from sitting on the hard seats with their legs up, crew members drag themselves out of the orbiter.

        It is the sixth launch postponement for Challenger.  It follows seven launch postponements in December and January for Columbia.  And this is to be NASA's most ambitious year: 15 shuttle missions are planned.

        As the crowd leaves the viewing stands, NASA's mission management team convenes inside the launch control building to plan tomorrow's try.  NASA asks its shuttle contractors to assemble any pertinent data for what looks to be the coldest launch ever.

        Outside the control center, rows of fruit trees edge up within a mile of the building.  More than 1,500 acres of oranges, grapefruit, tangelos and tangerines grow around it on government land under lease to private growers.

        Citrus workers nearby start flooding ditches around their groves at KSC.  But NASA workers do not have time to drain the 300,000 gallons of water at the launch pad.  The water is used to cool the tower after liftoff and flood the pad to suppress damaging sound waves at ignition.

        They pour in antifreeze instead.  They let the pipes drip.  And they switch on the shuttle's heaters.

        Grove owners prepare for a long night, but they've handled freezes before.

        Shuttle contractors are facing this trouble for the first time.

        The phone rings in Arnold Thompson's office at the Morton Thiokol Inc. plant in Brigham City, Utah.

        It's Boyd Brinton, a colleague, calling from NASA's Marshall Space Flight Center in Huntsville, Ala.  There could be a problem, he says.  A cold front is bearing down on Florida.

        ''Are you concerned?'' Brinton asks.

        ''You bet,'' Thompson says.  ''Yes, I am.''

        The supervisor of rocket motor cases for Morton Thiokol, Thompson thinks right away about the seals on the solid rocket boosters.  This is part of his area of expertise.  It's short notice, though.  Challenger is scheduled to lift off early the next day, and this problem of cold affecting the joints between the booster's segments is far from resolved.

        Only one thing to do.  Attack it like any other engineering task.  Go rationally.  Be thorough.  Get the team working on it.  He asks his people to collect some figures on heat transfer to get a predicted temperature of the booster joints.

        Thompson then calls Robert Ebeling, manager of ignition systems and final assembly of the solid rocket motors at the plant.  Ebeling, in turn, fills in the other engineers on the details.

        Immediately, one booster engineer, Roger Boisjoly, has his suspicions too.  He did not like the joint design under the best of conditions.  And for several months he's been considering this very problem of cold affecting the O rings -- the seals that act like giant washers to keep extremely hot gases from escaping.

        Boisjoly has envisioned the O rings as working like sponges in warm weather.  Then, they are nice and flexible; they can mold themselves into gaps.  But in freezing temperatures they would function like a brick shoved into a crack.  A leak from the booster joint means a 6,000-degree blowtorch cutting through to the shuttle's external fuel tank.

        Six months ago, he had warned Thiokol management about his fears in a memo.  He told them that if the problem were not fixed, ''the result would be a catastrophe of the highest order -- loss of human life.''

        Boisjoly has examined the seals from other flights.  In the case of the coldest O rings yet recorded before any launch, he found jet-black, burned material between the rings -- evidence of a temporary leak.  Yet even that launch lifted off in much warmer weather, in the 60s.  Nothing like the sub-freezing cold coming to Florida.

        Ebeling has heard enough.  Maybe they can't predict a major failure with absolute accuracy, but the freezing temperatures are well beyond their experience.
 

4 P.M.

        Friends and families of the astronauts, tired from the tension of waiting this morning, have left KSC and are settling back down at their hotels by about 4 p.m.

        The blastoff has been delayed before.  But this morning was the toughest.  Now some of the well-wishers will have to leave.

        It's a difficult decision.  Carl McNair would like to stay and see his brother fly.  They are very close, and he really doesn't want to go.  But he's got to get back to his data processing consulting firm in Atlanta.

        Carl and his wife, Mary, who is pregnant, will drive back.  They can watch the launch on TV before going to work in the morning.  They say goodbye to the rest of the family.  His mother, Pearl, says she is staying.

        She is a retired schoolteacher and still lives in Lake City, S.C. -- the small town where she raised her boys.  Ron is a hero there.  Signs at the city limits declare that motorists are entering the hometown of Dr. Ronald E. McNair, astronaut.

        The schools in which Mrs. McNair taught, the classes her sons attended, were segregated and their resources meager.  Still, she taught her children discipline.  And in all Ron put his mind to, he excelled.  Academics: a doctor of physics.  Music: a skilled saxophonist.  Karate: a black belt. And yet, high above her in the Florida sky is another peak to which he will rise.

        Through her teachings and his efforts, he will rise.  It swells a mother with pride.  Yes, she will stay on.

        In their plain dormitory rooms on the third floor of KSC's Operations and Checkout Building, the seven astronauts are trying to unwind before their 5 p.m. bedtime.

        Christa McAuliffe is eating dinner with her husband, Steve.

        This is their second pre-launch evening in a row.  Earlier Steve had joked about the irony of a simple bolt grounding the nation's symbol of technological success.  But over the last several months, both Steve and Christa have expressed complete confidence in NASA.  The agency doesn't take risks.  It won't take chances.

        Of course, there's always that tiny possibility that something will go wrong.  Nothing is perfect.  But compare that to the thrill of the Ultimate Field Trip and the chance to explain space to millions of students -- some of whom might find their futures there.

        The tingle of nerves, though, is natural.  Christa has wondered about that moment on the catwalk, 150 feet above the launch pad.  She has compared it to waiting in line for a roller coaster.  Scary, but fun.

        During her four months of training, Steve, who is a lawyer, has been in charge of housekeeping.  Their lives have been open to the media, which have been filing happy reports about a man forced to learn housework and keep up with his two young children.

        Christa, of course, has been calling home.  And Steve, of course, has been keeping her up on the family activities.  Their son, Scott, 9, understands and is excited.  Their daughter, Caroline, 6, doesn't quite understand all that's going on.  Once when McAuliffe left on one of her NASA trips, the camera caught Caroline crying, telling her mom that she didn't want her to go.

        Some comforting words.  Some confidence-building hugs.  And, finally, everyone was reassured.

        But Caroline still has not quite figured out how all this shuttle stuff will happen to her mom.  Once when Christa phoned, Caroline asked, ''Mom, are you in space yet?''

        But the 6-year-old is in Florida now and she'll be able to see her mom soar.  When she grows older and understands its importance, she'll be glad to have the memory.

        Steve and Christa have been married 15 years.  They were high school sweethearts before that.  When they finish dinner, they kiss goodbye.

        It's still early in the evening, so from her room in astronaut quarters, McAuliffe calls some friends to pass the time, to relieve some of the keen anxiety of waiting for the moment she has worked so hard to enjoy.

        Thiokol engineer Ebeling, in Utah, needs to talk to another Thiokol engineer -- Allan McDonald, director of the solid rocket motor program, who is in Florida at KSC.

        When Ebeling reaches him, McDonald is at the home of another Thiokol employee, Carver Kennedy, in Titusville.

        Ebeling lists the concerns of the Utah engineers.  The cold.  The lack of complete data relating that to the booster seals.  McDonald says they will round up all the weather data they can at KSC and call back.  It's getting close to 5 p.m.

        Kennedy grabs the phone and dials the launch operations center at KSC.  What is the latest on the cold front?  He hangs up and turns to McDonald.  It's going to get down to 22 degrees at 6 a.m.

        What?  This seems way out of the realm of all other launches.  A lot of new variables.  Untested situations.  McDonald calls Ebeling in Utah.  ''This is very serious.''

        McDonald believes the Thiokol engineering team knows more about the solid rocket motors than anyone.  They build them.  They live with them.  It must be these people who make the final judgment.  Launch or scrub, he says, ''This decision should be an engineering decision, not a program management decision.''

        He tells Ebeling they need to get all their facts in line.  Get Bob Lund, vice president of engineering, involved.  Meanwhile, he'll call the engineers from Marshall.

        Those relatives and friends who can stay over are making plans for tomorrow morning.

        Bob Burrows will stay another day.  He and his wife knew shuttle pilot Michael Smith when he was growing up on a farm near Beaufort, N.C.  Burrows taught him to fly at a little airport there, and now he wants a chance to see Smith's first blastoff.  His former student will take the skills he gave him into a region of the sky that Burrows can never hope to see.

        Marvin Resnik has come from Akron, Ohio, to see his daughter, Judy, fly her second shuttle mission.  Though she avoids all public attempts to enshrine her in a category, she is, in fact, the first Jewish astronaut and the second American woman in space.

        In her first trip aboard Discovery in 1984, Judy Resnik held up a sign that said, ''Hi Dad.''  The picture was beamed back to earth and to her father, who still calls her ''Little,'' a childhood nickname short for ''Little Judy.''  He is not about to miss his daughter's exciting day.

        Claude Onizuka of Kona, Hawaii, makes plans to organize all his brother's well-wishers and get them back to Cape Canaveral on Tuesday morning.  In all, 66 of Ellison Onizuka's friends and relatives have come.  They are staying at the Quality Inn on International Drive in Orlando.  Ellison, the first Japanese-American to fly into space, is a hero in their native state of Hawaii.

        Claude still talks to him two or three times a week; he wished him good luck over the phone Saturday.  Now he's left with the business of organizing his brother's admirers.  To get the whole group over to see the launch, Claude figures they need six vans.  The launch is scheduled for 9:38 a.m., so allowing for stragglers and unforeseen delays, he decides to set his alarm for 5 a.m.  That's nearly 90 minutes earlier than his brother's wake-up call.

        Of all the relatives, Bruce Jarvis may have had the least trouble waiting.  He and his wife, Ellen, live in Orlando.  They do not have far to drive to watch his son Greg -- an engineer for Hughes Aircraft Co. in Los Angeles -- sail through his first flight.

        Like the other family members, Jarvis brings his camera each time the shuttle is scheduled to fly.  He and his wife look forward to applauding, shooting some pictures and then accepting the congratulations of neighbors when they go home.
 

5 P.M.

        Along with the citrus growers, other farmers are taking precautions across Florida as the sun begins to fade.

        Fern growers and strawberry growers are switching on their sprinkler systems.  The spray will leave a coating of ice on their plants and perhaps insulate them from harsher, sub-freezing cold.

        But the citrus groves around KSC do not have sprinkler systems.  Leasing the fields on five-year contracts, growers do not want to invest that kind of money in fields they might lose.

        When the U.S. government began to purchase the 212 square miles for the space center in 1962, the groves already were thriving.  Rather than abandon them and risk losing an important piece of the Space Coast economy, the government agreed to contract out the fruit trees by bids.

        Steve Simmons, grove supervisor for the 500 acres of grapefruit and oranges leased by Mims Citrus Growers Association, is prepared for the long watch.

        In his small office in nearby Mims, he tunes the television to a weather station and gets the coffee started.  Other grove workers gas up the trucks they will use to drive to temperature checkpoints during the night.

        Stan Carter, the general manager who watches over 800 acres near KSC for Sullivan Victory Groves, has headed home to Cocoa Beach to get some warm clothes and some rest.

        He was born and raised in the citrus business.  He knows the freeze-watch procedure.  An employee will call him when the temperature slips below freezing.

        Then he'll fill a thermos with coffee, grab a pocketknife for cutting open fruit and head to the Cape.

        This is an old routine for a veteran grower.
 

5:45 P.M.

        Ebeling and the engineers in Brigham City, Utah, are amassing the new data on the cold.

        It doesn't look good, but they can't make the no-launch call.  The decision-making process for any launch is a pyramid that works its way up from the bottom.  After another round of calls, the engineers decide to set up a teleconference.

        At 5:45 p.m, hookups are established among engineers at Morton Thiokol in Utah, the Marshall center in Alabama and KSC in Florida.

        Thiokol engineers review their findings.  They believe it's going to be too cold for the O rings to work.  The liftoff must wait, at least until noon, for warmer temperatures.

        Judson Lovingood, deputy manager of Marshall's shuttle projects office, is listening in Huntsville.  He thinks they are building a case for delay.  He can see the arguments falling into place.  But his boss, Stanley Reinartz, manager of the shuttle projects office, is listening at KSC and he hears it differently.  To him, they just are ''raising some questions and issues.''

        They reach no resolution, however.  This is preliminary.  Arnold Thompson's people in Utah are still bringing in new figures on heat transfer.  And some of the higher-level managers could not be found in time to participate.

        All sides agree, though, they need to set up another, even larger conference in about three hours.  In the meantime, all pertinent Thiokol data are to be telefaxed to Huntsville and KSC.
 

6:30 P.M.

        At about 6:30 p.m., Lovingood telephones Reinartz at the Holiday Inn at Merritt Island, where the visiting Marshall employees stay during a launch.

        It seems to Lovingood that if Thiokol continues to oppose the launch, then NASA will have to agree to a delay.  Also, it seems appropriate to notify higher NASA authorities -- Levels I and II on the pyramid of launch responsibility -- of the issues to be discussed.  Get their input.  Prepare them for a possible delay.

        After Reinartz hangs up, he speaks with Lawrence Mulloy, manager of the solid rocket booster project at Marshall.  They decide to visit two high-level Marshall officials staying at the motel.

        They go over to the room of William Lucas, director of the Marshall center.  James Kingsbury, director of science and engineering at Marshall, also is there.

        Reinartz and Mulloy inform the two of the upcoming teleconference.  Reinartz, however, considers the issue manageable at his level -- Level III -- and chooses not to recommend involvement of the higher levels of shuttle program management, which coordinate all three space centers during a launch.

        Lucas, who is known as a demanding man, requires rigorous, scientific conclusions, and those are not yet available on the O rings.  Besides, none of the three NASA centers wishes to be blamed for a postponement, especially in light of the several delays already and the packed schedule of 15 flights this year.  Competition to avoid blame is fierce.

        Meanwhile, in Utah, Thiokol engineers keep gathering their data and preparing their charts.  Some are typed.  But time is short, so some are hand-lettered.  They start telefaxing them to Huntsville and Cape Canaveral.

        Night is falling over KSC.  A chill settles over Challenger.  The spaceship, glowing in the beams of artificial lights, sits upright on the scrubby, coastal flatlands between the Banana River and the Atlantic Ocean.  Offshore, in the recovery area, the wind howls, churning waves.

        At 7 p.m., Stan Carter gets a call from his assistant in the groves at KSC.  It's already 30 degrees out there.

        What?  Carter can't believe it.  He thinks the man has been nipping a little to pass the time.  It's about 10 degrees higher in Cocoa Beach.  And that doesn't make sense.

        Surrounded by the Indian and Banana rivers, the groves by the Cape's Vehicle Assembly Building usually benefit from the warmth of the waterways.  When cold air knifes across the rivers, it mingles with the rising warmth, blunting the chill and protecting the trees.

        This cold seems way ahead of schedule.  But Carter figures he might as well get out there and see what in the world is going on.

        Keeping with the NASA schedule, the astronauts have been preparing for bed.

        NASA has set their bedtime at 5 p.m., but at least one of the crew -- McAuliffe -- stays up to 7 p.m. phoning friends.

        Crew members know nothing about the growing debate on the safety of their ship.  According to the guidelines, they do not have to know.  And anyway, NASA's spectacular safety record is comforting.

        In 1970, the agency had saved the crew of the Apollo 13 moon mission after a liquid oxygen tank exploded in flight, knocking out the main engine.

        The astronauts breathed oxygen from their lunar module and used its engines (never intended for such an emergency) while NASA plotted a route to take them around the moon, gently nudging them back to Earth.  The rescue was world-renowned.

        A shuttle had been saved, too.

        On June 26, 1984, computers detected engine trouble on Discovery and shut down the launch just four seconds from liftoff.  Two of the three engines already had roared to life.  Hydrogen flames ignited in short bursts, but the automatic water spray doused them.  Judy Resnik was on board that day.

        But this is 1986, and the ambitious number of flights and the decreased number of safety checks has been worrying chief astronaut John Young.  Young, who has a planetarium named for him in his hometown of Orlando, believes the agency is pressing too hard.  He wants concern for safety to return to the high level established after the Apollo fire.

        That fire killed astronauts Virgil Grissom, Edward White and Roger Chaffee while the three ran routine tests in a sealed command module, perched atop a rocket at the Cape on Jan. 27, 1967.  In 25 years and 55 manned missions, they were the only astronauts to die.

        As the Challenger astronauts lay down to sleep, it is 19 years -- to the day -- since that fire.
 

8:45 P.M.

        Along the grove roads at KSC, Carter has been driving back and forth to his six temperature checkpoints.  It is about 8:45 p.m.

        Although the long nights can be wearying, they can hold some pleasant surprises.  The groves around the space center are located within the Merritt Island National Wildlife Refuge, and sometimes the headlights of Carter's four-wheel-drive pickup flash across possums, raccoons and armadillos scampering out of the way.  He sees one small, brown fox tonight.

        Coffee thermos by his side, Carter rides through the darkened groves to check the readings on his mercury thermometers.  They confirm what his assistant told him earlier.  There seems to be some kind of cold cell sitting on the island.

        Carter decides to call his boss in Cocoa.  His boss also has been checking the temperature at his own home.  It reads about 10 degrees higher than the chilled air around the fruit trees.  Carter says he was surprised, too.  But Carter figures his boss's reaction must be like his own earlier: The guy must be drinking.

        The second teleconference begins just before 9 p.m.

        Between Thiokol in Utah, KSC in Florida and Marshall in Alabama, about 35 executives, managers and engineers are ready to participate.

        The large conference room at Thiokol is on the second floor of a two-story building.  A large table about 20 feet wide and 50 feet long dominates the room.  There is a rounded, flat microphone in the center of the table and a microphone on the ceiling.  A large screen for graphic displays is set up against one wall.

        Roger Boisjoly begins the scientific discussions.  He is a completely bald man who speaks dryly, but whom some describe as atypically emotional for an engineer.  His shiny, slick head makes him seem more like an Uncle Fester than a Yul Brynner, more friendly than fierce.

        Picking up his papers, he goes over details on the two charts he has telefaxed.

        Chart 2-1, as everyone can see, is titled ''Primary Concerns.''  The first listing is ''Field Joint -- Highest Concern.''

        He directs their attention to another point just below.  ''If erosion penetrates primary O ring seal, then high probability of no secondary seal capability.''

        Chart 2-2 is headed ''Joint Primary Concerns.''  It hits at the same point: ''If threshold is reached, then secondary seal may not be capable of being pressurized.''

        Boisjoly keeps the discussion scientific, but he's trying to convey deep concern.  Those in Huntsville and at the Cape ask for a couple of technical clarifications.  But the Thiokol presentation proceeds smoothly.

        Boisjoly cites data from Discovery Flight 51-C in January 1985.  Here is evidence that hot gases blew by an O ring during the secret military mission on which Onizuka had flown.

        When 51-C returned, he says, shuttle workers discovered blackened grease in the joint.  Make no mistake about it.  It was black -- just like coal.  Jet black.

        The temperature of the seals on that flight had been the lowest yet measured -- 53 degrees.  According to the latest prediction, the Challenger's joint seals would go below freezing, 29 degrees.

        Others in the room in Utah give their reports.  Then Bob Lund, vice president of engineering at Thiokol, is ready to read off his recommendations.  They are written on one of the charts he's prepared.

        ''Recommendations: O-Ring temp. must be equal to or above 53 degrees Fahrenheit...  The best simulation worked at 53 degrees Fahrenheit.''

        Lund, the highest-ranking engineering officer at Thiokol, tells his listeners that until the temperature reaches 53 degrees, ''I don't want to fly.''

        Boisjoly sits back.  He feels good.  That was a good presentation.  They have gathered a lot of new data quickly, argued cogently and drawn their conclusions logically.  A good job.  He notices that of the 10 or so Thiokol engineers present, none has expressed a pro-launch opinion.

        But Mulloy, who oversees the solid rocket booster program for Marshall, breaks in from KSC and interrupts Boisjoly's feeling of content.

        Sitting in the conference room near the Launch Control Center, Mulloy is critical.  He attacks the logic of the argument.  It's inconclusive.

        A large, broad-shouldered man, Mulloy has a forceful personality.  He speaks with a deep voice, tinged with a Southern accent.

        Previous launches and all available evidence, he argues, show that given a primary and a backup seal, the joint will hold.  None of the engineering data seems to change that basic rationale.

        Then the NASA chorus begins: Quantify your claim.  Prove it.

        Boisjoly hears another voice on the phone network.  Another critique.  Booster seals on Flight 61-A in October 1985 also showed evidence of blow-by, and that launch occurred at 75 degrees.  Why, then, is the blow-by so crucial?

        But in colder temperatures, Boisjoly says, the seals show much more blow-by and that is indeed telling us that lower temperature is a factor.

        Cold gas tests indicate the O rings will work at 30 degrees, Mulloy responds.

        George Hardy, deputy director of science and engineering at Marshall, agrees with Mulloy.

        Hardy, sitting in the teleconference room in Huntsville, which has a large U-shaped arrangement of tables, is a distinguished-looking man with a full head of white hair.  He reinforces Mulloy.  The second seal is sufficient.

        The challenge starts again: Quantify your claim.

        Boisjoly says he has been trying to put together the data since October, but he has no other proof to offer.  He just knows the expected temperature is ''away from goodness in the current data base.''

        Mulloy believes the engineers are trying to establish new launch rules on the eve of the launch.  Currently, there aren't any restrictions for how cold the joints can be, and the previous constraints have served for 24 previous shuttle launches.

        If he follows the reasoning in Utah, it might be spring before it's warm enough to blast off.  And this year's launch schedule is NASA's most ambitious, with 15 shuttle missions planned.

        ''My God, Thiokol,'' Mulloy says.  ''When do you want me to launch, next April?''

        The challenge sinks in.

        Lund in Utah asks, ''What did we miss?''

        ''Well, I would like you to consider those other thoughts that we have had down here,'' he says, referring to his earlier arguments.

        Mulloy has another question.  Would Joe Kilminster, Thiokol's vice president for space booster programs, be willing to launch?

        Not over the recommendations of the engineers, Kilminster replies.

        Reinartz, manager of Marshall's shuttle project office, had only recently become Mulloy's superior.  From the conference room at KSC, he asks Hardy for his reaction to the Thiokol recommendations.

        ''Appalled,'' is how Hardy, in Huntsville, puts it.

        Would he overrule the contractors?

        No, not if they recommend against launching.

        The arguments slow.  They've been at it almost two hours.  It's 10:30 p.m.  The rooms grow quiet.

        Impasse.

        In Utah, Kilminster asks for five minutes for the Thiokol group to caucus among themselves.  But before they break off from the phone network, McDonald, Thiokol's manager of the solid rocket motor project, interjects from KSC.  He ranks just below Kilminster and Lund on the Thiokol flow chart, but above Thompson and Boisjoly.

        McDonald asks his Thiokol co-workers in Utah to consider a point made by Hardy about the secondary O rings being sufficient to seal the joint.

        Although McDonald is against the launch, his statement leaves Marshall's Hardy and some Thiokol managers as seeing him in favor of it.
 

10:30 P.M.

        Something odd is happening in these discussions.  It occurs subtly and without the engineers realizing it.  But the dynamic changes.  Different attitudes emerge.

        Before, Marshall's managers have always made the Thiokol engineers prove it was safe to fly -- the major customer demanding that its contractor prove the product would work.  This time, it seems as if the NASA managers from Marshall are trying to make them prove the booster joints will fail -- like making sure the first pull of the trigger will kill in a game of Russian roulette.

        But by the time Kilminster asks for a caucus, the engineers still have not grasped the change in the discussion.

        In the Thiokol conference room, Jerald Mason, senior vice president and the highest-ranking participant, speaks first.  They must, he says, make a ''management decision.''

        Wait a minute.  What's going on?  Thompson, who started the engineers working on the booster seal problem, thinks Mason is trying to cut them out of the caucus.  He jumps up from one end of the table, grabs his notepad and walks toward the management group.

        He drops his pad down between Mason and Cal Wiggins, vice president and general manager of the space division.  Here's the problem.  This is what's got him worried.  He tries to sketch it out.  He can't prove it will fail, he says, but the risk is higher than they should take.

        Thompson, a low-key but confident man, watches the faces.  These are his friends he is arguing with.  But all he sees are stern looks.

        Boisjoly is watching, too.  He sees that Thompson isn't getting through, so he grabs some photos and tries to reinforce his colleague.

        Look, here's the crux.  The residue from the blow-by during the warm weather launch is not nearly as great, nor as black, as the stuff from the coldest launch.  The colder the weather, the greater the chance of joint failure.  He's seen the material himself.  Here are photos.

        Then he stops.  No one is listening.  Thompson has already given up.  It seems to Boisjoly that his company's management is under a lot of pressure from the NASA people to launch.  But he has had his chance.  There is nothing left to say.  He returns to his seat.

        The caucus is stretching beyond five minutes into a half hour.

        Mason turns to his managers.  They seem to believe the O rings will perform.  Then he addresses Lund, who an hour earlier had read the recommendations against launching.

        ''Take off your engineering hat,'' Mason tells him.  ''And put on your management hat.''

        After discussing how to formulate their decision, the managers take a poll.  Kilminster helps conduct it.  Thompson watches him.  He wants to see if Kilminster will look at him to signal for input from the engineers or to read the expression on his face.

        But Kilminster doesn't look.  There is no eye contact.  Only management is polled.  Mason favors launch.  Kilminster does, too.  Same with Wiggins.

        Where does Lund stand?  He begins thinking over all that's been said.  There really isn't any way he can actually prove it will fail.

        In the groves, Carter has seen his second fox of the night, darting along the road near KSC.

        The cold has begun to worry him.  It looks like it's going to go below 27 degrees for several hours before the sun rises.  That's the temperature at which cold damages fruit and can ruin trees.  Water in the field ditches is starting to freeze.

        Out on launch pad 39B, Challenger's heaters are working, trying to fight off the cold.

        Water at the launch tower drips from the emergency showers that cool the structure after liftoff and suppress any fire that might occur.  The temperature keeps dropping.  The wind blows.  Mist strikes the cold metal, and ice forms.

        While the Thiokol conference continues, the discussion continues at KSC between McDonald and Mulloy.

        McDonald, who directs the solid rocket motor program for Thiokol, is described by colleagues as a straight-talking, decisive man who avoids rashness in his debates.

        He tells Mulloy, who is sitting close by, that he can see why Marshall would balk at waiting for it to warm up to 53 degrees.  But even if the engine is qualified to 40 degrees, how can they fly below that?

        Mulloy responds that the criterion for the solid rocket fuel is 40 degrees and they will be well above that.

        ''That's asinine,'' McDonald says.  The solid rocket fuel is itself an insulator from the cold.  It won't indicate trouble in the joints.

        ''If we're wrong and something goes wrong on this flight,'' McDonald says, ''I wouldn't want to have to be the person to stand up in front of a board of inquiry and say that I... told them to go ahead and fly this thing.''

        It's now unanimous among the Thiokol managers.  Lund has reconsidered.  The teacher will fly.  Thiokol re-establishes the phone link, and Kilminster announces the decision to the listeners at KSC and Marshall.

        From the Cape, Reinartz asks for any further comments.  None is voiced.

        Mulloy asks Thiokol to telefax the recommendations to KSC and Marshall.  The teleconference ends about 11 p.m.

        Sitting at the Thiokol conference table, Boisjoly feels defeated.  He disagrees with the decision.  But what else can he do?  He argued as persuasively as he thought he could.  He and the rest of the engineers file out of the room.

        At KSC, though, McDonald keeps arguing.

        If the cold is not sufficient reason to delay, then ice on the launch pad certainly is.

        The ice will be monitored, Mulloy says.

        How about conditions in the ocean recovery area?  They fall outside the launch rules.

        That is not necessarily a reason to postpone, Mulloy says.  According to the guidelines, it's an advisory call.

        The telefaxed recommendations reach KSC about 11:45 p.m.  McDonald goes to get them.  Signed by Kilminster, the last lines say:

        ''MTI recommends STS-51L launch proceed on 28 January 1986...''

        After Thompson leaves the teleconference room at Thiokol, he drives home.

        He does not agree with the decision tonight and feels badly about it.  He is ill at ease.

        Once inside his home, he tells his wife about the discussions.  He says he's worried about the launch.  He doesn't want to watch it in the morning.  He won't rest well tonight.

        In keeping with launch guidelines, Mulloy and Reinartz put in a call to Arnold Aldrich, who as team leader of the NASA mission management could veto the launch.  He is the second-highest man on the launch pyramid.

        Aldrich is at his motel in Titusville.  They talk about weather conditions in the recovery area.  The wind, Mulloy says, will probably keep ships from recovering both the main parachutes of the booster and the frustrum, a piece near the top of the booster.

        They do not mention to Aldrich the discussions on booster joints.  Mulloy believes that is a Level III decision -- solvable at the space center level -- and the case has just been closed.  It does not need to be escalated to Aldrich on Level II.

        Aldrich considers the recovery situation.  He decides that shouldn't stand in the way of launching.

        When the KSC group breaks up around midnight, the temperature is still slipping.  It is 30 degrees at KSC.  It's slightly lower in some spots in the groves.  But all across Merritt Island it is dropping.
 

TUESDAY, JANUARY 28, 1986

1:30 A.M.

        Out on the pad, at 1:30 a.m., the icicles are growing.  The mercury falls another degree, down to 29.

        The ice crew goes out to inspect the shuttle, and supervisor Charlie Stevenson sees ice all over the upper level and on the crew's emergency escape path.  He spots icicles 2 feet long.

        He knows the danger.  The launch will shake it all loose.  Falling debris could damage the shuttle's heat tiles, which protect the orbiter from the extreme temperatures of re-entry.

        Radio transmissions begin to crackle across several communications channels used by members of the ice crew and contractors for the shuttle.

        Stevenson tells the control center, ''I'd say the only choice you got today is not to go.''

        Carl and Mary McNair arrive home in Atlanta.

        They are beat after the long drive.  They bring in their luggage and settle down.  Before going to sleep, though, they set their alarm to be sure to get up to see the launch.
 

3 A.M.

        In Downey, Calif., workers for Rockwell International, the prime contractor for the orbiter, are monitoring the ice inspection through television hookups from the Cape.  They've never seen this much ice before.

        It is 3 a.m., and the digital countdown clock keeps ticking.  The temperature drops again to 27.

        The biting cold is taking its toll.  It causes an oxygen level sensor on the shuttle to fail.  It knocks out a hazardous-gas detector at the pad.  Several video cameras stop.  One radio channel quits.  A thick coat of ice covers a communications box.

        Ice is everywhere.  Despite antifreeze, water solidifies in the sound-suppression troughs at the pad.  Icicles hang on the frame between the external fuel tank and the orbiter.  And they hang in thick rows across the upper levels of the launch tower.

        Six miles away, the astronauts are sleeping.  Not knowing about the problems on the pad or the discussions in the conference rooms, they will awaken with innocent joy.

        It is a joy that shuttle commander Dick Scobee, who builds planes in his spare time, once described like this: ''It's a real crime to be paid for a job that I have so much fun doing.''
 

5 A.M.

        Riding through the groves, Stan Carter makes his 5 a.m. checks.

        Ice particles coat his thermometers.  He starts to feel helpless.  His livelihood depends on the fruit and he has done everything he can.

        He picks a couple of grapefruit and oranges and slices them open.  Slush inside.  This stuff will have to go to the cannery.  Most of the crop is still on the trees, and now it will have to be picked in a hurry to salvage anything.

        Prices are best for fresh fruit, but nothing can be done.  He checks more thermometers.  It's 22.5 in the south section of his groves.  It's 24 degrees up near the Vehicle Assembly Building.

        Claude Onizuka awakens in the Quality Inn on International Drive in Orlando.  It's 5 a.m.

        Maybe today, after so many delays, maybe today will be the day that his brother, Ellison, will get to fly with the teacher into space.  He dresses and helps round up the 65 other friends and relatives who have come to watch.

        Driving along the empty streets east to KSC, they are tired but excited.  They look forward to the time they can release their pent-up cheers.  Onizuka feels the cold outside.  He knows his brother hates the cold.

        As Onizuka's family and friends stir at the hotel, William Lucas, the stern director of Marshall Space Flight Center, enters the Launch Control Center at KSC.  Last night, he had heard about Thiokol's concerns when Mulloy and Reinartz spoke with him in his hotel room.  In between, though, he has heard nothing.

        So, spotting Mulloy and Reinartz in the control center, he goes over and asks how the issue was resolved.

        Booster manager Mulloy says Thiokol expressed initial concern about the cold, but the company decided to recommend launch.

        Reinartz, the Marshall shuttle chief, does not mention that all the Thiokol engineers opposed launching.  And as far as Mulloy is concerned, the situation is resolved.  Pulling out a copy of the telefaxed Thiokol recommendation, he shows it to Lucas.
 

6 A.M.

        Although their wake-up call is not scheduled for almost another half hour, the crew, anxious to go, is up around 6 a.m.

        There's plenty of time to shower and get a bite to eat.  In good spirits, they prepare for another try on the launch pad.  They sit down to breakfast around a big, rectangular table.  Someone has placed an arrangement of American flags and roses in the center.  To one side is a model of the shuttle, to the other a large white-frosted cake.  The cake bears the emblem of shuttle Flight 51-L.

        The seven seem relaxed.  They are dressed in their short-sleeved NASA shirts and tennis shoes.  Most wear jeans.  The breakfast fare is steak and eggs, and Resnik takes two helpings of steak.

        After breakfast, they change into their blue NASA jumpsuits.
 

7:30 A.M.

        At Rockwell in California, Rocco Petrone, president of the company's space transportation systems division, enters the launch support room where his people have been monitoring the icing situation on the launch pad all night.  It's 7:30 a.m. in Florida, and the California workers are worried.

        Will falling ice strike the shuttle on liftoff?  Will it damage the tiles?  They don't know yet.  The engineering team is working on it.  More information is coming in from Florida.

        John Tribe, Rockwell's systems engineering director, is watching the scenes on closed circuit TV at KSC.  He's been gathering data, and he doesn't like what he sees.  He relays his concerns back to Robert Weaver, a co-worker in Downey.

        ''Looks bad, eh?'' says Weaver.

        ''Ice does look bad, yeah,'' Tribe says.  ''Every platform has had water running on it all night, and there are just -- some of the close-ups of the stairwells look like something out of Dr. Zhivago.  There are sheets of icicles hanging everywhere.''

        ''Sounds grim.''

        ''The big concern is nobody knows what the hell is going to happen when that thing lights off and all that ice gets shook loose and comes tumbling down.  And what does it do then?  Does it ricochet?  Does it get into some turbulent condition that throws it against the vehicle?''

        ''Okay,'' Weaver says.  ''We didn't see this when we had the icing conditions before?''

        ''No, and they didn't run the showers all damn night before.  They ran the showers this time and ran 'em pretty heavily by the look of it.  The drains froze up and they all overflowed.''

        ''Oh.''

        The astronauts get a final weather briefing in a conference room.

        They hear about the cold temperatures.  There is some ice.  Could be a delay.

        But they hear nothing about the debates of the night before.  Such matters have been left behind as the countdown ticks along.  Like dominoes, the decisions keep falling into place, tripping the next one, and the next, right on schedule.

        All the relatives and VIPs are keeping to the schedule, too.

        Assembling at a public park near the space center, they shiver while waiting for NASA buses to take them to the special viewing area at KSC.

        Standing by his wife, Bob Burrows is eager to get into the space center.

        He's proud to be there. He wants to see Michael Smith fly.

        Two dozen NASA buses pull up in convoy.  The joyous well-wishers climb on board.

        With an energetic bounce, the crew walks out of the astronaut quarters just before 8 a.m.

        About 35 people, mostly NASA officials and the press, watch.  Reporters shout questions.

        The astronauts are excited.  They smile.  Some wave.  It's clear and cool and Scobee thinks it's a beautiful day for his great love: flying.

        Linda Long, a publicity consultant hired by NASA to work with McAuliffe, is making her own videotapes.  During the last several months, her professional relationship has been changing into a friendship.

        She has thought about the future when she will be able to reminisce with McAuliffe about all the anxiety and all the laughs.  She shouts to the teacher.

        ''Looks like we're going this morning.''

        McAuliffe turns and smiles. ''Great.''

        The crew members enter the shiny van that will take them to the launch pad.

        Rockwell engineers still are trying to calculate whether ice will strike the shuttle during liftoff.

        It could bounce off the platform.  Could get into the slipstream.  Boosters could inhale it.  They've never been in this situation before.  It's inconclusive.  They can't be sure.

        John Peller, vice president of engineering for Rockwell in Downey, has been coordinating the ice study.  He gets on the communication network to speak to another Rockwell vice president, Robert Glaysher, at KSC.

        There is going to be a mission management meeting with NASA at Kennedy soon.  They need to make a final decision on the ice.

        ''We still are of the position that it's a bit of Russian roulette,'' Peller says.  ''You'll probably make it.  Five out of six times you do playing Russian roulette.  But there's a lot of debris.  They could hit direct, they could be kicked up later by the solid rocket boosters, and we just don't know how to clear that.''

        ''Okay.  Our position fundamentally hasn't changed,'' Glaysher says.  ''We'll just go in now... and express it. ''

        ''And obviously, you know, it's their vehicle,'' Peller says, ''and they can take the risk, but our position is as stated.''
 

8:15 A.M.

        In the space center, the VIP grandstands are filling by 8:15 a.m.

        McAuliffe's parents wait along with thousands of other spectators in the center and along the roads of the Space Coast.  In the viewing stands, the tension starts again.  At Concord High School, the students bring out their party hats and horns again.  And, again, the immediate families of the crew members file into the fourth-floor office in the Launch Control Center.

        Steve McAuliffe keeps an eye on 9-year-old Scott and 6-year-old Caroline -- the girl who has been a little confused all along about just how and when her mom gets into space.

        But her mom is on the launch tower elevator now, 3 miles away, riding up to the catwalk with the crew.  The elevator stops 150 feet off the ground and Christa McAuliffe steps out.  The drills are over.  This is the moment -- the one she has likened to standing in line for a roller coaster -- a mixture of nervousness and happy anticipation.

        In front of her lies the open-air catwalk to the 2,220-ton spaceship.  Freezing air gusts through the gray platform.  She feels the bite of 25-degree weather.

        Looming above her, the 15-story, orange-brown fuel tank rises over the spaceplane.  Inside it, 530,000 gallons of liquid oxygen and hydrogen wait to do their volatile work.  Left and right, the two solid rocket boosters point to the sky like twin towers.

        The boosters are packed with 2.2 million pounds of solid fuel that burns at 6,000 degrees Fahrenheit.

        Below her, ice covers the bottom segment of a booster.  The ice crew has just finished another inspection.  They took temperature readings as low as 8 degrees near the rear of the ship.

        With the rest of the crew, McAuliffe crosses over the gangway and into the white room, a sterilized chamber outside the shuttle attached to the spaceship's hatch.  There, workers help the crew members prepare.  Helmets go on.  Arms are poked through the flight vests, which have small, inflatable pillows in the back to ease the discomfort of waiting on the hard seats.

        Johnny Corlew, a NASA quality assurance inspector, presents the teacher with a red apple.  McAuliffe thanks him.  The space agency has adopted the teacher's symbol for the mission.  Along with Halley's comet, which the crew hopes to observe, the official 51-L patch features a small apple.

        ''Save it for me,'' McAuliffe says.  ''And I'll eat it when I get back.''

        Paul Arnold, a technician with Lockheed Space Operations Co., asks the crew to autograph a picture that his son can hang up in Geneva Elementary School in Seminole County.  At the top, McAuliffe inscribes her familiar motto, ''Reach For The Stars.''

        Ground crew members wipe off the astronauts' shoes to prevent contamination in the shuttle.  Then the crew climbs through the hatch and into the ship.

        Commander Scobee and pilot Smith take their front seats on the flight deck.  Behind them sit mission specialists Resnik and McNair.  In the middeck below are Onizuka, Jarvis and McAuliffe.  Amid the switches, screens and gauges, the crew settles in.  They buckle their seat straps into place.

        In Downey, Calif., Petrone has seen enough ice.  He calls his vice presidents at KSC.

        From what he is seeing, he tells them, the company can't recommend launch.
 

9 A.M.

        After a long night of checking temperatures, Stan Carter and Steve Simmons head back to their homes about 9 a.m.

        Simmons' groves at KSC have fared well.  Very little damage.  He is feeling good when he reaches his house and falls asleep.

        Carter is not as happy.  But all in all, the citrus crops fared well.  It did not turn out to be a killer freeze like last year.

        Still, record lows were set all over the state.  The temperature dropped to 26 in Orlando; 22 in Daytona Beach; 13 in Tallahassee; 16 in Jacksonville.

        When he gets home, Carter decides to take a shower before trying to get some rest.

        The team assembles at KSC to review the ice.

        Arnold Aldrich, NASA's mission management team leader, calls on the two Rockwell vice presidents.  What is their position?

        ''Rockwell cannot assure that it is safe to fly,'' Glaysher says.

        The other vice president, Martin Cioffoletti, concurs.  They cannot give their 100 percent backing that it is safe to fly.

        But no one gives a clear and definitive no-go.  Aldrich says that other calculations by engineers at Johnson Space Center in Houston and at KSC indicate ice will not endanger the shuttle.

        Feeling reasonably confident, he makes his final decision: Launch.

        Sitting on their cold seats, but exuberant at being in the shuttle, the astronauts crack jokes.

        ''Wow, boy, the sun feels good this morning,'' Smith says.

        ''Ice skating on the mobile launch platform?'' Scobee asks.

        From the middeck, Onizuka complains. ''Kind of cold this morning.''

        Smith, knowing that Onizuka hates the cold, rubs it in.

        ''Up here, Ellison, the sun's shining in.  At least we've got the crew arranged right for people who like the warm and cool...  Got you out of the sun.''

        ''My nose is freezing,'' Onizuka says.

        But Resnik, so controlled in media settings, seems the most animated this morning.  Responding to a communications check, she shouts: ''COWABUNGA!''

        Sonny Carter, the astronaut support person, also has entered the shuttle.  He is helping McAuliffe check the radio transmitter in her helmet.

        ''Okay, Christa, you oughta be able to hear me.''

        ''Real fine.''

        McAuliffe then hears a ground controller from Firing Room 3 in the Launch Control Center say, ''Good morning, Christa.  Hope we go today.''

        ''Good morning.  I hope so, too.''

        A heating tube, controlled by the closeout crew, shoots a blast of hot air through the cabin.  Resnik breaks out laughing.

        ''Whooooh!'' Onizuka says.

        ''Yeeehah!'' says Smith.

        ''It was right up my you-know-what,'' says Resnik.  ''Ellison thought it was great.''

        Ground control radios a message.  Liftoff will be delayed.  Launch constraints forbid blasting off until the air temperature reaches 31 degrees, and mission management wants more ice to melt off the pad.

        Scobee says, ''Commander understands a T equals zero no earlier than 11:08...  Everybody hear that?''

        ''Unfortunately,'' Jarvis says.

        ''So, not so fast,'' Scobee says.

        Sonny Carter announces he is finished with the checks and is leaving the cockpit.  But the waiting continues and the hard seats are getting uncomfortable.

        ''Feel like I'm at the four-hour point of yesterday,'' Smith says, referring to Monday's long delay.

        ''I feel like I'm past it,'' says Resnik.  ''My butt is dead already.''

        The crew and the controllers keep to their checklists.  Onizuka is looking for the ice team.

        ''Ice pickin','' Scobee says.  Some of the others laugh.

        ''They're probably making a fortune selling coffee and doughnuts out at the viewing areas,'' Jarvis says.

        ''How about that,'' says Scobee.  ''We should have gotten some.''

        ''A few hot toddies,'' says Resnik.
 

10 A.M.

        By 10 a.m. the temperature has risen to freezing -- 32 degrees.

        Spectators are gathering around coffeepots, gulping down the hot liquid.  Souvenir merchants have put McAuliffe's image on the usual assortment of mementos.  Her father, Ed Corrigan, is seated in the grandstands.  He is wearing two buttons showing his daughter dressed in her light blue astronaut uniform.  Christa's sister, Lisa, wears a button as well.  So does her brother, Christopher.

        All around, friends and excited onlookers, in winter coats, keep their cameras and binoculars at hand.  Some third-graders from Concord have a banner ready to raise when the shuttle roars.  ''Go Christa,'' it says.

        Inside the orbiter, the crew continues with their technical checks.  In the tradition of adventurers taking danger with a joke, they also keep up their good-natured kidding.

        ''My bun is dying,'' Resnik says.

        ''Ellison and I will massage it for you,'' says Jarvis.

        ''Ellison's not even interested,'' Resnik says.

        ''I'll bet you could wake him up for that,'' Jarvis says.

        At the launch pad, the ice team continues its inspections.  They are breaking up ice in the water troughs.

        At the press mound, Linda Long is fielding requests from photographers to get Christa's parents, the Corrigans, to move closer, within camera range.  She walks over and relays the requests.

        They agree it would be fine.  ''Christa would want to see what our faces look like,'' Grace Corrigan says.
 

11 A.M.

        In an hour the temperature has risen to 37 degrees.  The Launch Control Center radios Scobee.  ''We're planning to come out of this hold on time.''

        That's good news to the commander who loves to fly.  ''All righttt!''

        Controllers make another radio check with the crew members.  Payload specialist McAuliffe answers with her final response: ''PS1 loud and clear.''

        Resnik, though joking with exuberance, has been keeping a check on the technical procedures.  She reminds Scobee of the sequence to one of their checks.

        ''Do a 99 before you do that.''

        ''Oh, sorry, I'll do it.''

        A few minutes later she tells the commander: ''Oh, Scobes.  You may or may not get a dp/dt, but you might also get the hi-press alarm as the cabin expands as we go up.''

        ''Okay, Judy.''

        The excitement is building in the grandstands.  It will reach exhilaration in the crew cabin.

        In Firing Room 3, launch director Gene Thomas checks with the controllers monitoring their rows of consoles.  All affirmative.  Engineering director Horace Lamberth asks ice supervisor Stevenson for an update.

        ''Okay, Horace, it is beginning to melt a little bit and we did sweep off everything...  There was some pretty good size pieces there...  The vehicle looks good... ''

        ''OK, Charlie, thank you.  Gene, you got any questions?''

        ''None from here,'' Thomas says.  ''Has anybody else got any questions?''

        Lamberth looks at the employees around him.

        ''I'm getting everybody's head shaking in the right direction.''

        In the control room section reserved for the Marshall managers, Lawrence Mulloy has his headset on and is standing.

        He looks through the large overhead windows that face east, toward the Atlantic Ocean, where the shuttle sits up high on the launch pad.  Though 3 miles away, the man who led the attack on the Thiokol position feels like he is looking right up the tailpipe.

        James Kingsbury, the Marshall director of science and engineering, is standing, too.  He will advise the program managers in case problems occur.

        On the roof above them, the immediate families have gathered.  They wait behind a handrail on the building's flat roof.

        Just to their left, the Vehicle Assembly Building towers 520 feet into the air.  Off to their right, the grandstands are alive with spectators and members of the press.

        In Houston, flight director Jay Greene is sitting in the middle of the Mission Operations Control Room.

        He is commander of the vehicle during ascent.  He checks with his team members, who will help communicate with the crew during liftoff.  No problems.  All affirmative.

        Nearby, in Building 4, about 20 astronauts have been gathering around a TV monitor in their second-floor office.  After seeing the ice, David Leestma, scheduled to fly on the next shuttle, goes back to his desk, saying, ''Ah, they aren't going to launch.''

        But when word spreads that the launch is a go, he heads back, surprised at the decision.  The astronauts begin their wait, grouped around the TV, growing apprehensive.

        In Huntsville, Judson Lovingood, the deputy manager of Marshall's shuttle projects office, sits down and makes himself comfortable in the shuttle action center.

        In Brigham City, some of the Morton Thiokol employees are gathering in the teleconference room to watch the launch.  But Thompson and Boisjoly, still worried about the O rings, don't want to see it.  Thompson is in his office on the floor below, talking with some of his people about the discussions of the night before.  Boisjoly is nearby, working in his office.

        Even with a teacher on board today, the liftoffs have become too routine for ABC, NBC or CBS to pre-empt national programming.  Cable News Network is the only national TV network going live as the catwalk pulls away from the ship.  The three Orlando affiliates break into regular programs to televise shuttle coverage on their own.

        ''Seven minutes,'' says Scobee.  ''There goes the arm.''

        ''Bye-bye,'' Resnik says.  ''Tighten your straps.''

        Reminders are radioed from Mission Control to snap the visors down tight.

        ''Roger.  Visors are coming down,'' Scobee says.

        The crew continues with their last-minute details.  Looks like there is no turning back.

        ''Welcome to space, guys,'' Scobee says.  ''Two minutes downstairs.''
 

T minus 1:47.

        ''Okay.  There goes the lox liquid oxygen arm,'' Smith says.

        ''Goes the beanie cap liquid oxygen vent,'' Scobee says.

        Onizuka jokes.  ''Doesn't it go the other way?''

        ''God, I hope not, Ellison,'' Smith says.

        The crew is laughing.  T minus 1:44.

        ''One minute downstairs,'' Scobee says.

        ''Cabin pressure is probably going to give us an alarm,'' Resnik says, referring to a routine caution alarm.

        ''Alarm looks good,'' says Smith.

        ''Thirty seconds,'' Scobee says.  ''...Fifteen.''

        T minus six.  The shuttle's main engine ignites.

        ''There they go, guys,'' Scobee says.

        The rumble begins below.

        ''All right,'' Resnik says.

        The three main engines are firing at 100 percent thrust.  ''Three at a hundred,'' Scobee says.

        ''All right,'' Resnik shouts.

        At 11:38 a.m., the countdown reaches zero.  The O rings are at 31 degrees, more than 20 degrees colder than for any other shuttle launch.  The solid rocket motors ignite.

        Less than a second later, the shuttle gives its first push toward the heavens.  Smith is looking skyward.

        ''Here we go,'' he says.
 

11:38 A.M.

        The deafening noise rises through the ship, unleashing powerful tremors that vibrate through the astronauts' bodies.

        Outside, the noise shakes the crowd at KSC.  Whoops and cheers begin for the 10th flight of Challenger.

        McAuliffe's parents, Ed and Grace Corrigan, stand side by side.  They smile and tilt their heads skyward, watching the graceful ascent.  Surrounding them are joyful faces and upraised binoculars.  Christa's sister, Lisa, shouts in happiness.

        The Corrigans hug.  Mrs. Corrigan lays her head on her husband's shoulder and puts her other hand on Lisa's shoulder.  Lisa raises her right hand to meet it.  Together.  Linked by hands, watching Christa.  Smiling.

        At Concord High School in New Hampshire, loud voices unite with a tumult of party horns and noisemakers.  Finally, the long wait is over.  The students cut loose with a youthful revelry usually reserved for great varsity games.

        All across the country, students cheer.  This is their event.  This, they have been told, is their future.  You may work in space some day.

        Stan Carter, after showering off from his night in the groves, steps out on his balcony in Cocoa Beach to watch the liftoff.  He couldn't get to sleep without seeing the shuttle.  He has seen all 24 previous launches.  Some from the groves at KSC.

        Even 4 miles away from the launch pad, he's felt the thunder and seen the fruit shaking gently on the trees.

        Unnoticed, on the shuttle's right booster, the first puff of smoke forms.  In less than a second, there are seven more puffs of smoke.

        The first two minutes of flight are the most dangerous part of the ascent.  There is no escape system for the astronauts, and nothing could be done anyway until the huge solid rockets finish firing and drop away.

        The smoke puffs stop.  The gap seems to seal itself.

        At seven seconds, the shuttle starts its roll maneuver, arcing backwards so that its tank faces the sun and the orbiter faces the ground.

        ''Houston,Challenger roll program,'' Scobee says.

        In Houston, astronaut Richard Covey acknowledges.  ''Roger, roll Challenger.''

        Inside the cabin -- exhilaration on technology's hottest ride.

        ''Go, you mother,'' Smith urges.

        ''Ooohh-kaaay,'' says Scobee.

        It's a feeling McNair loves.  He's a Ph.D. physicist, but he reacts to the all-encompassing thunder with a gut-level thrill.  He loves it so much that when visiting his brother in Atlanta, he would bring an audio tape of his first flight on the Challenger and play it on Carl's expensive stereo.

        He'd crank up the volume, sit down in front of the speakers and let the gusts of sound throb over him.  The house would shake.  But Ron would sit there, reliving the moment.  He finally blew the speakers.

        At 19 seconds into the flight, the shuttle adjusts its course, compensating for turbulence in the sky.  A force three times that of gravity pushes the astronauts down into their seats.

        At 35 seconds, the roll maneuver ends and the main engine thrust drops to 65 percent to reduce stress on the vehicle.

        ''There's Mach 1,'' Smith says, reporting that they have reached the speed of sound.

        Scobee notes the altitude.  ''Going through nineteen thousand.  Okay, we're throttling down.''

        On the roof of the Launch Control Center, the immediate families of the crew members watch the shuttle rise.

        Marvin Resnik is looking carefully.  In June 1984, he saw his daughter's launch stopped just seconds before liftoff.  He knows the dangers in the early part of the flight.  Seeing the shuttle rise above the tower, he relaxes a little.  The first part is over.

        The Challenger shoots up.  Looks smooth.  Rising nicely.  Keep going.  Keep going.

        In Atlanta, Carl McNair is getting ready for work at home.  He and his wife and his father are watching television.  It was a long wait, but this is what they wanted to see.

        Satisfied that everything looks good, Mary goes outside to warm up the car for the drive to work.

        Aboard a chartered plane full of staffers and press, Florida's Gov. Bob Graham is flying from Tallahassee to Jacksonville.  Just a few hours earlier he announced his campaign bid for the U.S. Senate.

        The pilot tells the passengers they can see the launch if they look out the window.  Everyone peers at the white tail climbing into the sky.

        Graham is jubilant.  Standing in the aisle, holding onto the seats, he says, ''This is a major omen for the campaign.''  He bounces up and down on his toes.

        The reporters swap shuttle headlines with him.  ''Graham Launches Campaign.''  Another offers, ''Graham Skyrockets To The Senate.''

        At 58 seconds, a flame appears on the right booster.

        At 59 seconds, the forces on the spacecraft reach their maximum dynamic pressure while the thrusting rockets fight against the pull of gravity.  Then, passing through that point -- called Max Q -- the shuttle accelerates again.

        ''Throttling up,'' Scobee says.

        But the shock of Max Q apparently has cracked the already damaged joint.  A plume of flame burns through the right booster.

        ''Feel that mother go!'' Smith says.  ''Woooohoooo!''

        The slipstream outside the shuttle deflects the 6,000-degree flame down toward the shuttle's external fuel tank.  The shuttle is 35,000 feet high, traveling at Mach 1.5, and a glow appears on the tank.  Hydrogen is leaking.

        The automatic control system kicks in, reacting to changes caused by the flame.  The left booster counters the yaw produced by the leak in the right.

        As far as the astronauts know, as far as ground control knows, all is normal.  Scobee checks the airspeed and finds everything A-OK.

        ''Reading four, eighty, six on mine,'' he says.

        ''Yep, that's what I've got, too,'' Smith says.

        In Houston, Gene Kranz, director of mission operations, is happily checking the data.

        Kranz, who trains the flight directors, has no specific role assigned to him on this launch.  But he has not missed a launch in about 25 years, going back to the days of Mercury Redstone 1.

        A controller lets him look over a console.  Out of habit, he calls up information about the boosters.

        The screen shows several readings -- from turbine speeds to tank pressures.  Then he checks to see how the main engines are responding.

        Covey, at Houston's Mission Control, relays a command to the shuttle: ''Challenger, go at throttle up.''

        ''Roger,'' Scobee says, ''go at throttle up.''

        At 70 seconds into the flight, the main engines are roaring at almost full force.  The astronauts are heading for orbit.  This is what they trained for, this is what they love.  In another 60 seconds, the boosters will burn themselves out.  They wait to feel that deceleration.

        At 72 seconds, the lower strut linking the right booster to the external tank breaks apart.  The booster pivots around its upper attachment, its nose cone smashing into the liquid oxygen tank.

        In Houston, Kranz sees a flicker on his screen.  He looks up.

        At 73 seconds, a flash erupts between the orbiter and the liquid hydrogen tank.  The radioed telemetry -- automatically transmitted data from the shuttle -- breaks up.  The crew is traveling at nearly 2,000 mph.  They are 46,000 feet high.

        And they know.

        ''Uh-oh,'' Smith says.

        The fireball erupts.  A great explosive cloud engulfs the shuttle.

        Pieces of the orbiter tear away.  Several large sections are spit out of the monstrous cloud.  Shooting out, the forward fuselage drags a mass of umbilical lines away from the payload bay.

        Still burning, the two boosters fly off in opposite directions, spurting white lines of smoke.  Two thick arteries of smoke and hundreds of dangling capillaries whip out of the red-yellow center in a quick spasm, trailing after hot chunks of metal.

        Kranz looks down.  On his computer screen, where the shuttle readings should be, he sees S's, signifying static.  He feels a struggle begin inside.  He sees it.  He understands.  He wishes he didn't.

        Elsewhere, in the firing rooms, in homes along the Space Coast, in Concord, N.H., in schoolrooms across the nation, people stop.

        On the roof of the Launch Control Center, NASA officials ask the immediate family members to come back inside.  A sick nervousness takes hold.

        Turning, Resnik knows it's bad.  NASA did this when they stopped his daughter's first flight.

        Spectators in the KSC grandstands are confused.  What is it?  Have the boosters separated?

        Above them the trails of smoke seem to cross.  What's wrong?  What's happening?

        In Houston, NASA commentator Steve Nesbitt is reading off the flight data.  He continues with his public narration, catching up on the backlog of information that comes in quicker than he can speak.

        ''One minute, 15 seconds,'' he says.  ''Velocity 2,900 feet per second.  Altitude nine nautical miles. Downrange distance seven nautical miles.''

        Then he, too, pauses.  Mission Control in Houston is hushed.  The controllers freeze in front of their computer screens.  They see S's by the readouts.

        At KSC, Kingsbury, too, watches his console.

        He turns away and peers up through the window to see the cloud.  What's gone wrong?  He sees the solid rocket boosters veering across the sky and thinks to himself, ''It couldn't have been the solids.''

        Mulloy sees the same thing and is also trying to figure out what happened.  The solid rocket boosters still seem to be flying.  He thinks to himself, ''The SRBs worked okay.''

        The room is silent.  They both realize the fate of the crew.  ''Oh, God,'' Kingsbury says.  ''No.''

        The two booster rockets zoom wildly across the sky.  One may be veering inland.  A range safety officer at Cape Canaveral Air Force Station orders their destruction.

        A radio signal is sent to ignite the explosive packages on the boosters, blowing the tops off.  Fuel spews from both ends of the rockets, stopping the forward thrust.  Slowing, they fall toward the ocean.

        Burrows, who taught Smith to fly, stands and watches the smoke, and he knows the truth.  It's hopeless now.  Next to him, his wife, Jean, keeps asking, ''Where's the shuttle?  Where's the shuttle?''

        He knows, but he can't say.  He tells her it's safe.  It will emerge on the other side of the cloud.

        At the Vehicle Assembly Building, 3 miles from the launch pad, several workers watch the sky, shocked into silence.

        For several seconds they do not speak.  Michael Duda, a heat tile specialist, keeps looking, staring.  It's not right.  He says to himself, ''This isn't happening.  It's a dream.  It isn't real.''

        Launch team member Richard Prickett is in the VAB.  ''My God,'' he thinks.  ''This can't be true.''

        Watching the fireball, Prickett begins to feel sick.  He has been part of this.  He's worked on this launch.  He feels like he has had a hand in killing seven people.

        Long, who had been videotaping the day, strains to see the shuttle, hoping to catch a glimpse of it sailing safely out of the fireball.  Everyone around her seems confused.  People seem to be moving in slow motion.  She feels like she's in a fog.

        She walks over to Jim Mizell, a former NASA engineer working as a public information officer on the press mound.

        ''I didn't see the orbiter.  I didn't see the orbiter.''

        ''They're going to RTLS,'' Mizell says, speaking the shorthand for return to launch site.

        Inside the firing rooms, controllers prepare.

        ''Personnel standing by for landing operations,'' the Lockheed test director says.  ''Personnel stand by.  Stand by.''

        The pause ends abruptly when the NASA public announcer speaks again.  ''Flight controllers are looking very carefully at the situation,'' he says.  ''Obviously a major malfunction.  We have no downlink...

        ''...We have the report from the flight dynamics officer that the vehicle has exploded.''

        At the roof of the Launch Control Center, two of the younger Smith children cry for their father.  ''Daddy, I want you.  You said nothing would happen.''

        NASA officials take them inside.  Marvin Resnik hears the crying and sees Ellison Onizuka's wife, Lorna.  He goes over to her.

        ''Are you all right, honey?''

        ''Yes,'' she says.  ''I'm okay.''

        She leans against a wall for support.  NASA officials try to explain what they know at this point.  Mrs. Onizuka is listening.  She braces and then slumps down.  The lights in the room flicker as she brushes against some switches.  A flight surgeon rushes over to help her.

        A little later, Bruce Jarvis falls ill and a doctor is called.  His wife says it's shock.  They were clapping for his son, her stepson.  They were taking pictures.  Then it happened.

        In the VIP grandstands, the friends and relatives moan, their spirits falling.  Exhilaration becomes despair.  McAuliffe's parents hug each other again, desperately.  Her sister grimaces.

        A NASA official climbs up the rows of bleachers and speaks to the teacher's parents.  ''The vehicle has exploded.''

        Mrs. Corrigan looks at him.  ''The vehicle has exploded?''

        The official nods silently.  The Corrigans are led away amid the anguish.

        Other parents in the stands hug their children.  A man bows his head and puts a hand up to his eyes.  A woman stands, holding her head between her hands.

        Linda Long searches for Steve McAuliffe's law partner, Leo Lind, to bring him over to help the astronaut's stunned husband.

        A man cries out, ''Oh God, no, please no.  That's not supposed to happen.''

        Another man slumps on the tripod of his camera.  A woman clasps her hands and touches them to her nose, almost in prayer.

        The sight in the sky sickens Brian Ballard.  That's his teacher up there.  He is one of the students from McAuliffe's high school who has come to watch the launch.  His stomach is spinning.  He grows nauseous.

        ''Back on the buses,'' an official says.

        Watching from a NASA viewing room, 69-year-old Elmer Thomas begins to feel ill, too.  It's in his chest.  It's tightening.

        He's been with NASA 21 years as a propulsion and solid rocket engineer.  He helped load the external fuel tank with liquid hydrogen through the night.  He's committed to his profession.  Now all his work is smeared across the sky in an ugly, fatal stain.

        He tries to get up, but his legs don't move.  He slumps down; colleagues call for help.

        Emergency workers take him to Jess Parrish Memorial Hospital, where injured astronauts would be taken in a launch pad emergency.  But he will never leave.  Two days later, he suffers a fatal heart attack.

        NASA knows it's hopeless.  The agency does not even alert the hospital in Titusville.

        Instead, it begins to gather its data.

        ''This is NASA test director on 212 and 232.  We request that all people stay off the telephones please.  Again, we're asking all people in the firing room to stay off the telephones, and also we do want to impound all data.

        ''I repeat, we want all personnel to stay off the telephones and we do want to impound all data.''

        Security teams lock the firing rooms at KSC.  Mulloy and Kingsbury begin to check with their people.

        The procedure is to get it all down on paper before any detail, even one that might seem inconsequential now, is lost.

        ''We need to get all systems to go back and start evaluating their data from about 10 minutes prior to main engine start all the way to the loss of data,'' a controller says.

        Someone calls for ice crew director Charlie Stevenson over the communications network.

        ''Hey, Charlie, make sure that all the film cameras and everything on the T minus zero and everything get impounded, too.  All the high speed film camera and everything.''

        ''Understand.''

        ''Charlie, did all the umbilicals and everything look normal?'' asks Horace Lamberth, KSC's director of engineering.

        ''It looked excellent, Horace,'' Stevenson says.

        In the moments that follow, controllers in Houston stare at their screens.

        Astronaut Fred Gregory throws both hands up in the air.  He looks over at astronaut Richard Covey.  Just a moment before, they were talking to the crew.

        Flight director Jay Greene orders security in the Houston control room to impound the data.  Then he leans back from his monitor.  Hand to his mouth, he stares down.

        William Williams, an engineer who works on the shuttle's controls, thinks about McNair and how the astronaut went out of his way to be kind to him.  It was back at Halloween, and Williams had invited him to a costume party.  But then McNair wound up scheduled for a session in the shuttle flight simulator.  Still, the astronaut showed his appreciation.

        Pressed for time, McNair donned the costume of an Arab sheik and drove over to Williams' place in Galveston for about an hour before rushing back to Houston to get to work.  Williams knows he won't forget that now.

        The 20 astronauts gathered around the television at their Houston office fall silent.

        Leestma knows.  They all know.  He turns to Bob Overmyer.  ''That's it.  It's all over.''

        Little else is said.  No conversation.  Nothing.  Astronaut Steve Nagel, who has flown two shuttle missions, knows there is nothing to say.  They watch TV for a little while and then get up and walk out.

        Leestma and Overmyer get in a two-man NASA jet and fly to KSC.

        ''Shut up!  Listen!''

        Shouts ring out in the Concord High School auditorium.  It can't be.  Students are weeping, teachers hugging.  Senior class president Carina Dolcino remains standing, staring, holding a paper horn, her party hat on her head.

        Principal Charles Foley dismisses classes and closes the school for the next day.  Counseling services will be available to those who need them.

        Later, he tells reporters that the students will be told to remember Mrs. McAuliffe's motto, ''Reach for the stars,'' and to keep believing in it, as she would want them to.

        A Concord radio station broadcasts somber music.  Sadness spreads through the town of 30,000.

        In Huntsville, Judson Lovingood thinks the explosive packs on the boosters may have blown up the shuttle.  He gets up in the shuttle action room and walks over to the adjacent console room to see if they have any information on that.  No one is sure.

        He thinks of the crew and he feels nervous.  He can't sit still.  He goes outside and walks around.  In a few minutes, though, he regains control of his emotions and goes back inside.

        Once back inside, he helps establish the Marshall investigative teams.  Looking through the preliminary data, they see that the chamber pressure on the right booster was slightly low.  Someone says that's normal.  Lovingood says no.  It could be important.  They keep searching.

        Lovingood's wife also works at Marshall Space Flight Center.  She knows better than to call.

        In Brigham City, a Morton Thiokol worker sticks his head in Thompson's office and tells him.

        Some of the people who have been listening to Thompson recount the events of the previous night begin to cry.  Thompson stands up and walks over to tell Boisjoly, who is in another office.

        Boisjoly starts to cry.

        In the CNN news studio in Atlanta, producers and reporters shake off the momentary daze and scramble into action.

        Dave Farmer, supervisor of producers, is in the back of the control room.  He calls his producer on the office intercom.  Get the correspondent talking about what they just saw.

        In New York, CBS news anchor Dan Rather goes running down the hall to the flash studio, which is always kept ready to go on the air.  All three networks are on within three minutes of each other.  CNN converts to full-time coverage of the explosion.

        White House aide Patrick Buchanan breaks into a meeting in the Oval Office, where President Reagan is speaking with chief of staff Donald Regan.

        Tonight the president plans to mention the achievements of NASA in the State of the Union address.  He had personally announced the Teacher in Space program on Aug. 27, 1984.

        ''Sir,'' Buchanan says, ''the shuttle's blown up.''

        They gather around a television.  Standing, Reagan watches a replay of the explosion.  His aides surround him.  In silence, he clasps his hands in front of him.

        The replays of the fireball begin on all three networks.  Speculation starts that the crew can never have known what hit them.

        Death, however, is not instantaneous.

        Following Smith's ''Uh-oh,'' there are a few seconds of frantic activity in the crew cabin.

        The fiery cloud that surrounds the shuttle probably does not blow out the windows.  Its concussive forces rock the crew and tear the cabin away from the orbiter but probably are not enough to kill the astronauts or knock them unconscious.

        The cabin shoots up from 48,000 to 65,000 feet, jamming the crew down into their seats with the force of acceleration.  Separating from the orbiter, the crew cabin rips away from its oxygen supply.  A couple of seconds of air are left in the lines.  Then breathing will stop.  Suffocation will begin.

        The astronauts have one chance to stave off death for a little while.  Small air packs, designed for use during emergency ground escapes, are attached to their helmets.

        At least two crew members turn on the valves of their air packs.  But, strapped against their seats, Smith and Scobee can't reach around to get to theirs.  From behind Smith, one of the crew members reaches over and turns on his air valve.  Smith can breathe.  At least three are now on.

        But no one can get to Scobee's.  The cockpit probably is losing cabin pressure.  The crew probably is blacking out.  The cabin begins its 12-mile drop, reaching 207 mph.  Hitting the surface of the Atlantic at that speed is like hitting concrete.  The fall lasts 2 minutes and 45 seconds.  The astronauts are strapped in their seats when they hit the water, 18 miles off the coast.

        Above the cabin, twisting white lines hang in the air.  Shuttle debris rains down for an hour.

        Citrus manager Stan Carter, standing on his balcony in Cocoa Beach, hears the sound of crackling and popping as the pieces fall.  On the Space Coast, the bells of Greater St. Paul Baptist Church begin to toll.

        Mary McNair is in her car in Atlanta, letting it warm up, when she hears the news on the radio.

        Though pregnant, though tired from lack of sleep, she rushes back inside the house.  Her husband is staring at the television.

        Carl does not believe it.  It's not real.  It's science fiction.  It's one of those ''What if?'' scenes.  He feels numb.

        Mary worries about her husband.  Carl is just 10 months older than Ron.  The two brothers were especially close.  They went to grade school, high school and college together.  They depended on each other.

        The phone starts ringing.  Friends are calling.  Carl can't think.  He wants to keep wishing it's not true.  What's he supposed to do?  Mary says they've got to get back to the Cape and find his mother.

        Okay.  That's right.  They repack.  In between phone calls, they try to make plane reservations.

        Traffic slows on Interstate 4 outside Orlando.  Passengers look into the eastern sky and point.

        Cars and pickups pull over to the side.  Passengers get out.  Some couples hold hands.  Some men hug.  They keep looking to the east, out over the ocean, to the two white plumes from the boosters.

        In department stores, people gather around televisions to watch the replays.  At Fashion Square Mall in Orlando, Kathy Hudson, a Sears employee, just shakes her head.  She has seen this replay too many times.  Each time, she relives her reactions as she watches the stages of the slow-motion explosion.

        At Columbia Restaurant on St. Armand's Key near Sarasota, manager Casey Gonzmart prepares to serve his customers, but he feels sick.  It's the same feeling he had in his gut when he was in high school in Tampa and he heard about the assassination of John F. Kennedy.

        The television keeps replaying the fireball.  Finally, Gonzmart can't watch it anymore.  So he turns it off.

        Drivers on I-4 flick on their headlights.  Lines of cars and trucks roll by, their low beams burning in silent tribute.

        Eastward, the crew cabin sinks below the surface.  It lands on the sandy bottom in 78 feet of water.
 

12:40 P.M.

        Graham's plane lands in Jacksonville at 12:40 p.m.

        As they pile into campaign buses, reporters hear about the explosion.  They rush back out to Graham, who also has been informed.

        ''We had the opportunity to experience the exhilaration of what we thought was going to be another American triumph in space,'' he says.  ''But we realize now how fragile that experience is.''

        He cancels his next campaign stops in West Palm Beach and Miami, and returns to Tallahassee.  He orders flags at state offices lowered to half-staff.
 

1:30 P.M.

        Gradually, the wind begins to clear away the dangling smoke from the sky.

        It is turning to wisps of vapor over the Space Coast.  In Orlando, a skywriter, unaware of the tragedy, has been practicing smiling faces in the cloudless air.

        Heat tiles from the orbiter begin washing ashore south of the Cape.  Passers-by pick them up and bring them to KSC.  They hand them over to officials, who are collecting any and all evidence.

        Work comes to a halt on Capitol Hill in Washington.  Members of Congress bow their heads in prayer.  The Senate chaplain says, ''We are reduced to silence.''

        Sen. John Glenn, D-Ohio, the first American to orbit the Earth, tries to place the disaster in context.

        ''Sometimes triumph is accompanied by tragedy,'' he says.  ''We had hoped to push this tragedy back forever, but it was not to be.  Let us carry their memory with us.''

        Sen. Jake Garn, R-Utah, had been at the Cape over the weekend to watch, but he could not stay after the postponements.  He flew in the shuttle in April 1985.

        Speaking before reporters in Washington, he recalls how Mike Smith watched over him like a ''mother hen'' during his own astronaut training.  Emotions welling up, he is overcome.
 

2:30 P.M.

        At about 2:30 p.m., security guards unlock the firing rooms at KSC.  Kingsbury hands his notes to a guard.  Security officers search briefcases to ensure that all the notes are turned in.

        Lucas, Kingsbury, Reinartz and Mulloy go to a room to review NASA films of the launch, but they see nothing significant.

        At CNN, Farmer has seen the fireball so many times the shock of its strange appearance is wearing off.  It becomes less a breaking news image and more a sight of horror.  What happened to the crew?  What do the families think when they see it?

        At one point, NBC's Tom Brokaw apologizes for the replays.  They may seem redundant to some, he says, but new viewers are tuning in all the time.

        NASA's Jesse Moore, who oversees mission management, calls a meeting in a conference room at the Launch Control Center.  He organizes four teams to investigate and search the computer data and the recovered debris.  The meeting is somber.  Some possible causes are offered.  No one is certain, though.

        Mulloy is dispatched to Patrick Air Force Base, 20 miles south, to debrief crews of the 12 aircraft that monitored the launch.  He talks to them for several hours and impounds their film and their notes.

        Then he drives back to KSC and reports to Aldrich and Moore.
 

5 P.M.

        At 5 p.m., Carl and Mary McNair are in a commercial airliner, a DC-9 -- just about the size of the shuttle orbiter -- headed for Melbourne Regional Airport, located 30 miles south of KSC.

        As they come in for a landing, the plane suddenly swerves to the right.  Out the window, McNair sees a small plane about 100 feet away.  A student pilot is in the way.  Though following instructions from the tower, the inexperienced pilot suddenly freezes and fails to obey a command to turn.  The airliner rocks back to level and narrowly misses the smaller plane just before landing.  McNair sits in his seat, shaking his head in disbelief.

        The president has canceled his State of the Union Message, but he decides to address the nation on national TV.

        ''Nothing ends here,'' Reagan says.  ''Our hopes and our journeys continue.  These people were dedicated to the exploration of space.  We can do no more to honor them, these courageous Americans, than to go forward with the program.''

        To the millions of children who watched, he says:

        ''I know it's hard to understand but sometimes painful things like this happen.  They're all part of the process of exploration and discovery, all part of taking a chance and expanding man's horizons.

        ''The future doesn't belong to the faint-hearted.  It belongs to the brave.  The Challenger was pulling us into the future, and we'll continue to follow.''
 

6 P.M.

        NASA brings the immediate relatives of the crew into the astronaut quarters at KSC, about 6 miles from the launch pad.

        The friends of the crew members are splitting up.  By 6 p.m., many are going home.

        What else can they do now?  The immediate families have been isolated.  There is nothing to stay for.  Bob and Jean Burrows are on the road, driving back to Michael Smith's hometown of Beaufort, N.C.

        Before they left, they had tried to find Smith's sister to comfort her.  But NASA had taken her to be with the immediate family.  The couple are quiet as they ride.

        NASA gives each family a separate room at the astronaut quarters.  There they are left with their loved ones in private grief.

        Carl McNair arrives and finds his mother, sitting in silence.  It seems to him that she doesn't want to accept what she has seen.  They hug.

        With Marvin Resnik is his stepdaughter, Linda Reppert.  She tries to comfort him.  She talked with Judy over the phone just yesterday.  Everyone knows how eager Judy was to fly.  That's the way she was.  She wanted to get going.

        Reppert tries to remain calm.  That's what Judy would have wanted.  They had a thing about being strong with each other.

        Officials notify the families that the president has directed Vice President George Bush and Sens. Garn and Glenn to fly to KSC to speak with them.  The family members agree to stay for that.  They want to hear something that will ease the numbing sorrow.

        Doctors are available.  NASA helps make arrangements for travel to get the families home.  The agency provides sandwiches, coffee and cold drinks to those who want them.  Word spreads that the official contingent has arrived.  The survivors gather in a lounge area and wait.

        June Scobee, the commander's wife, has been talking with the relatives, getting their support to keep the space program going.  It can't die with the deaths of the seven.  They wouldn't want that.  They didn't go into the program for that.

        The room is silent when the three politicians enter.  The survivors' reservoir of tears will fill again, but for now it has gone dry.  They are weary.  When everyone is in place, Mrs. Scobee, speaking for the families, makes a few remarks.

        She thanks the three for showing the concern to come here.  They appreciate that.  But they want them to know that they are united behind the space program.  They want it to continue.

        Bush and Garn express their sorrow.  The two talk about the sacrifice the families have made.  The country will always honor that.  They try to soothe.

        Then it's Glenn's turn.  He stands before them and looks at the tired grievers.  They could easily have been his family. He knew the risks.  He had faced them in the Mercury program when the first group of astronauts had wondered among themselves how many would survive.

        ''There are times,'' he says, ''when you devote yourself to a higher cause than personal safety.''  Their fathers, their husbands, their brothers are heroes, he says.  They were willing to risk their lives for the higher purpose.  It is the price that must be paid for triumph.

        Several of the relatives begin to break down.  Glenn cries, too.

        ''I know that the seven brave heroes were carrying our dreams and hopes with them,'' he says.  ''And I know that we will continue to carry their memories with us.''

        Afterward, the three men speak privately with the families.  They kiss the women.  They hug the men.  Glenn consoles the Resniks.

        He tells Reppert, ''Judy was a beautiful person.''
 

9 P.M.

        Kingsbury calls Huntsville about 9:30 p.m. for an update.  Nothing definitive.

        No one mentions O rings.  No one is saying, I told you so.

        Tired and feeling like the final answer was a long way off, Mulloy boards a NASA jet for Alabama.

        NASA arranges to take the Resnik family to Orlando International Airport and books them under an assumed name.  Soon they are in the air, headed back to Akron.

        The Burrows, after a solemn drive, reach Jacksonville and decide to spend the night at a motel.

        Watching TV at home in Atlanta, Dave Farmer, a producer with 18 years in television, starts to see the replays of the shuttle not so much as a newsman as just a man at home, relaxing after work.  The connection from the public to the astronauts seems very personal.  He starts to feel almost protective.

        In Huntsville, Lovingood goes home and talks with his wife and son.  They just say how terrible it is.  He sleeps restlessly.  He keeps thinking it is a bad dream.  It will be gone in the morning.
 

11 P.M.

        Mulloy lands in Huntsville about 11 p.m.  At home, he can't settle down.  He wants to talk and calls his ex-wife on the phone.  They talk for almost two hours.  Then, exhausted, he falls asleep.

        In Houston, Gene Kranz, a burly ex-military man with a crew cut, has been pouring himself several drinks.  It doesn't do any good.  He can't sleep.

        On Merritt Island, Linda Long goes back to her room at the Holiday Inn.  She has a stiff drink.  Hers doesn't help either.  Every time she lies down and closes her eyes, she sees the explosion.

        Kingsbury is at the same motel.  He just lies in bed, thinking.  What happened?  What happened?

        The Jarvises drive to their red brick apartment in Orlando.  Bruce Jarvis has recovered from the shock at the space center, but he worries about how his son's good qualities will be kept alive.  It can all seem so useless, amounting to nothing.

        Completely fatigued, he is asleep while his wife answers the phone to accept the condolences of friends.
 

WEDNESDAY, JANUARY 29, 1986

        The weather warms all along the Space Coast on Wednesday.

        Just north of KSC, it is 62 in Titusville.  It is the day that McAuliffe was to have taught the first of her two lessons, conducting a tour of the spacecraft.  The Ultimate Field Trip.

        Closeout crew member Paul Arnold presents the autographed crew picture to his son's elementary school in Seminole County.  Long escorts the Corrigans on a flight back to Framingham, Mass.

        Allan McDonald leaves KSC and flies into Huntsville to help the people he had argued with two nights before.  He had told them he would not want to be the person to stand before a commission and defend the launch.

        But when he meets Mulloy in Huntsville, he is professional.  He doesn't mention the cold.  They just do the work that has been assigned to them.

        Arnold Thompson flies in from Utah.  He does not say anything either.  There is plenty to do without speaking out of turn.

        At CNN, Farmer is among several people who believe the network should stop showing the explosion.

        CNN agrees on an informal policy.  Show the shuttle to the point of the explosion.  Don't use video of the fireball unless the story deals specifically with how the flame ate through the booster or the sequence of the joint failure.

        Bruce Jarvis hears of the scholarships that are being set up in the names of the astronauts.  He would like to help pick some of the students.  Maybe he would see in one of them the qualities he saw in Greg.  That way, perhaps, something of the spirit he admired in his son would be preserved.

        He consoles himself thinking that, for a few seconds, Greg was enjoying the thrill of fulfilling a dream.  He remembers his son's last words to him.  They came over the phone a couple days before.

        ''Dad,'' he said, ''I love you.''

        Mary McNair begins a diary of her thoughts and her husband's reactions, so that the baby girl she will give birth to in a couple months will one day know how her parents loved the uncle she will never see.

        Sonar-equipped ships search for remains of Challenger on the ocean floor.  A few days later, they will find a battered helmet and some of the education materials that the Teacher in Space had prepared.

        Six weeks later, divers will recover the remains.  The seven funeral services will follow shortly.

        In May, Thompson returns to Utah.  His workers welcome him back with a little get-together and a welcome home sign.

        In the spring, Long, who had videotaped the astronauts, seeks help from a psychologist.  She is having a recurring nightmare.  The fireball.  Christa.  It's still the first thought on her mind each morning.

        The psychologist tells her that if she wants to bury the memories, she must talk about them.  And if she wants people to remember the good qualities she admired in Christa, she must talk about them.

        In June, her parents ask her to play the videotapes she made and Long watches them for the first time.  She looks closely.  There they are, bouncing out of the astronaut quarters on that cold morning.  There are the smiles.  The shouts.  The wave from Christa.

        She leaves the room while the images are running.