Blogarchiv

Raumfahrt-History - 1986 Space-Shuttle STS-51L Challenger Mission

.

sts-51l-patch

NASA - STS-51L Mission Profile

 
  
722342main_challenger_full_full.jpg
STS-51L Crew (l-r): Payload Specialists Christa McAuliffe and Gregory B. Jarvis, Mission Specialist Judith A. Resnik, Commander Francis R. Scobee, Mission Specialist Ronald E. McNair, Pilot Michael J. Smith, Mission Specialist Ellison S. Onizuka.
Credits: NASA
The first shuttle liftoff scheduled from Pad B, STS-51L was beset by delays. Launch was orginially set for 3:43 p.m. EST, Jan. 22, slipped to Jan. 23, then Jan. 24, due to delays in mission 61-C. Launch was reset for Jan. 25 because of bad weather at the transoceanic abort landing (TAL) site in Dakar, Senegal. To utilize Casablanca (not equipped for night landings) as alternate TAL site, T-zero was moved to a morning liftoff time. The launch postponed another day when launch processing was unable to meet the new morning liftoff time. Prediction of unacceptable weather at KSC led to the launch being rescheduled for 9:37 a.m. EST, Jan. 27. The launch was delayed 24 hours again when the ground servicing equipment hatch closing fixture could not be removed from the orbiter hatch. The fixture was sawed off and an attaching bolt drilled out before closeout was completed. During the delay, cross winds exceeded return-to-launch-site limits at KSC's Shuttle Landing Facility. The launch Jan. 28 was delayed two hours when a hardware interface module in the launch processing system, which monitors the fire detection system, failed during liquid hydrogen tanking procedures.

Just after liftoff at .678 seconds into the flight, photographic data shows a strong puff of gray smoke was spurting from the vicinity of the aft field joint on the right solid rocket booster. Computer graphic analysis of the film from the pad cameras indicated the initial smoke came from the 270 to 310-degree sector of the circumference of the aft field joint of the right solid rocket booster. This area of the solid booster faces the external tank. The vaporized material streaming from the joint indicated there was not a complete sealing action within the joint.

Eight more distinctive puffs of increasingly blacker smoke were recorded between .836 and 2.500 seconds. The smoke appeared to puff upwards from the joint. While each smoke puff was being left behind by the upward flight of the shuttle, the next fresh puff could be seen near the level of the joint. The multiple smoke puffs in this sequence occurred at about four times per second, approximating the frequency of the structural load dynamics and resultant joint flexing. As the shuttle increased its upward velocity, it flew past the emerging and expanding smoke puffs. The last smoke was seen above the field joint at 2.733 seconds.

The black color and dense composition of the smoke puffs suggest that the grease, joint insulation and rubber O-rings in the joint seal were being burned and eroded by the hot propellant gases.

At approximately 37 seconds, Challenger encountered the first of several high-altitude wind shear conditions, which lasted until about 64 seconds. The wind shear created forces on the vehicle with relatively large fluctuations. These were immediately sensed and countered by the guidance, navigation and control system. The steering system (thrust vector control) of the solid rocket booster responded to all commands and wind shear effects. The wind shear caused the steering system to be more active than on any previous flight.

Both the shuttle main engines and the solid rockets operated at reduced thrust approaching and passing through the area of maximum dynamic pressure of 720 pounds per square foot. The main engines had been throttled up to 104 percent thrust and the solid rocket boosters were increasing their thrust when the first flickering flame appeared on the right solid rocket booster in the area of the aft field joint. This first very small flame was detected on image enhanced film at 58.788 seconds into the flight. It appeared to originate at about 305 degrees around the booster circumference at or near the aft field joint.

One film frame later from the same camera, the flame was visible without image enhancement. It grew into a continuous, well-defined plume at 59.262 seconds. At about the same time (60 seconds), telemetry showed a pressure differential between the chamber pressures in the right and left boosters. The right booster chamber pressure was lower, confirming the growing leak in the area of the field joint.

As the flame plume increased in size, it was deflected rearward by the aerodynamic slipstream and circumferentially by the protruding structure of the upper ring attaching the booster to the external tank. These deflections directed the flame plume onto the surface of the external tank. This sequence of flame spreading is confirmed by analysis of the recovered wreckage. The growing flame also impinged on the strut attaching the solid rocket booster to the external tank.

The first visual indication that swirling flame from the right solid rocket booster breached the external tank was at 64.660 seconds when there was an abrupt change in the shape and color of the plume. This indicated that it was mixing with leaking hydrogen from the external tank. Telemetered changes in the hydrogen tank pressurization confirmed the leak. Within 45 milliseconds of the breach of the external tank, a bright sustained glow developed on the black-tiled underside of the Challenger between it and the external tank.

Beginning at about 72 seconds, a series of events occurred extremely rapidly that terminated the flight. Telemetered data indicated a wide variety of flight system actions that support the visual evidence of the photos as the shuttle struggled futilely against the forces that were destroying it.

At about 72.20 seconds the lower strut linking the solid rocket booster and the external tank was severed or pulled away from the weakened hydrogen tank permitting the right solid rocket booster to rotate around the upper attachment strut. This rotation is indicated by divergent yaw and pitch rates between the left and right solid rocket boosters.

At 73.124 seconds, a circumferential white vapor pattern was observed blooming from the side of the external tank bottom dome. This was the beginning of the structural failure of hydrogen tank that culminated in the entire aft dome dropping away. This released massive amounts of liquid hydrogen from the tank and created a sudden forward thrust of about 2.8 million pounds, pushing the hydrogen tank upward into the intertank structure. At about the same time, the rotating right solid rocket booster impacted the intertank structure and the lower part of the liquid oxygen tank. These structures failed at 73.137 seconds as evidenced by the white vapors appearing in the intertank region.

Within milliseconds there was massive, almost explosive, burning of the hydrogen streaming from the failed tank bottom and liquid oxygen breach in the area of the intertank.

At this point in its trajectory, while traveling at a Mach number of 1.92 at an altitude of 46,000 feet, Challenger was totally enveloped in the explosive burn. The Challenger's reaction control system ruptured and a hypergolic burn of its propellants occurred as it exited the oxygen-hydrogen flames. The reddish brown colors of the hypergolic fuel burn are visible on the edge of the main fireball. The orbiter, under severe aerodynamic loads, broke into several large sections which emerged from the fireball. Separate sections that can be identified on film include the main engine/tail section with the engines still burning, one wing of the orbiter, and the forward fuselage trailing a mass of umbilical lines pulled loose from the payload bay.

The explosion 73 seconds after liftoff claimed crew and vehicle. The cause of explosion was determined to be an o-ring failure in the right solid rocket booster. Cold weather was determined to be a contributing factor.

Mission Highlights (Planned)

The planned orbital activities of the Challenger 51-L mission were as follows:

On Flight Day 1, after arriving into orbit, the crew was to have two periods of scheduled high activity. First they were to check the readiness of the TDRS-B satellite prior to planned deployment. After lunch they were to deploy the satellite and its Inertial Upper Stage (IUS) booster and to perform a series of separation maneuvers. The first sleep period was scheduled to be eight hours long starting about 18 hours after crew wakeup the morning of launch.

On Flight Day 2, the Comet Halley Active Monitoring Program (CHAMP) experiment was scheduled to begin. Also scheduled were the initial "teacher in space" (TISP) video taping and a firing of the orbital maneuvering engines (OMS) to place Challenger at the 152-mile orbital altitude from which the Spartan would be deployed.

On Flight Day 3, the crew was to begin pre-deployment preparations on the Spartan and then the satellite was to be deployed using the remote manipulator system (RMS) robot arm. Then the flight crew was to slowly separate from Spartan by 90 miles.

On Flight Day 4, the Challenger was to begin closing on Spartan while Gregory B. Jarvis continued fluid dynamics experiments started on day two and day 3. Live telecasts were also planned to be conducted by Christa McAuliffe.

On Flight Day 5, the crew was to rendezvous with Spartan and use the robot arm to capture the satellite and re-stow it in the payload bay.

On Flight Day 6, re-entry preparations were scheduled. This included flight control checks, test firing of maneuvering jets needed for re-entry, and cabin stowage. A crew news conferences was also scheduled following the lunch period.

On Flight Day 7, the day would have been spent preparing the Space Shuttle for deorbit and entry into the atmosphere. The Challenger was scheduled to land at the Kennedy Space Center 144 hours and 34 minutes
---
s86-25192
S86-25192 (January 1986) --- Two payload specialists in training for the STS-51L mission, and a payload specialist from STS-61C share a "zero-gravity" flight aboard a KC-135 aircraft over the Gulf of Mexico. Left to right are United States Representative Bill Nelson (Democrat, Florida), Sharon Christa McAuliffe, and Barbara R. Morgan. The congressman is a payload specialist for the STS-61C mission. McAuliffe is the prime payload specialist for the Teacher-in-Space Project aboard the STS-51L mission; and Morgan is her backup. The photo was taken by Keith meyers of the New York Times. EDITOR'S NOTE: The STS-51L crew members lost their lives in the space shuttle Challenger accident moments after launch on Jan. 28, 1986 from the Kennedy Space Center (KSC). Photo credit: NASA
51l-s-029-1
51L-S-029 (28 Jan. 1986) --- Crew members of the STS-51L mission are seated for breakfast launch morning in the Operations and Checkout Building prior to liftoff of the space shuttle Challenger scheduled for 9:38 a.m. The launch was scheduled for Jan. 27, 1986, but was delayed 24 hours due to unacceptable cross winds. Crew members left to right are Ellison S. Onizuka, mission specialist; Sharon Christa McAuliffe, payload specialist; Michael J. Smith, pilot; Francis R. Scobee, commander; Judith A. Resnik and Ronald E. McNair, mission specialists; and Gregory D. Jarvis, payload specialist. EDITOR'S NOTE: The STS-51L crew members lost their lives in the space shuttle Challenger accident moments after launch on Jan. 28, 1986 from the Kennedy Space Center (KSC). Photo credit: NASA
647444main-chal-51lcrew1-12x16-1

STS-51L Crew

Crew members of mission STS-51L stand in the White Room at Pad 39B following the end of the Terminal Countdown Demonstration Test (TCDT). From left to right they are: Sharon "Christa" McAuliffe, Gregory Jarvis, Judy Resnik, Commander Dick Scobee, Ronald McNair, Michael Smith and Ellison Onizuka. The crew was killed on Jan. 28, 1986, when Challenger broke apart during ascent. 

s86-25293-1

S86-25293 (30 Oct. 1985) --- Barbara R. Morgan and Sharon Christa McAuliffe (right) are pictured during a visit to NASA's Kennedy Space Center (KSC) Launch Complex 39 to witness the launch of the space shuttle Challenger. McAuliffe is scheduled to launch aboard the space shuttle Challenger, STS-51L mission, herself early next year as the United States' first in-space citizen observer. Morgan is the backup for the Teacher-in-Space Project's payload specialist position. The photo was taken by Keith Meyers of the New York Times. EDITOR'S NOTE: The STS-51L crew members lost their lives in the space shuttle Challenger accident moments after launch on Jan. 28, 1986 from the Kennedy Space Center (KSC). Photo credit: NASA

v1p22

Immediately after solid rocket motor ignition, dark smoke (arrows) swirled out between the right hand booster and the External Tank. The smoke's origin, behavior and duration was approximated by visual analysis and computer enhancement of film from five camera locations. Consensus: smoke was first discernible at .678 seconds Mission Elapsed Time in the vicinity of the right booster's aft field joint.

v1p25

Multiple smoke puffs are visible in the photo above (arrows). They began at .836 seconds and continued through 2.500 seconds, occurring about 4 times a second. Upward motion of the vehicle caused the smoke to drift downward and blur into a single cloud. Smoke source is shown in the computer generated drawing (far right).

v1p26

At 58.788 seconds, the first flicker of flame appeared. Barely visible above, it grew into a large plume and began to impinge on the External Tank at about 60 seconds. Flame is pinpointed in the computer drawing between the right booster and the tank, as in the case of earlier smoke puffs. At far right (arrow), vapor is seen escaping from the apparently breached External Tank.

v1p28

Camera views indicate the beginning of rupture of the liquid hydrogen and liquid oxygen tanks within the External Tank. A small flash (arrows above) intensified rapidly, then diminished.

v1p29

A second flash, attributed to rupture of the liquid oxygen tank, occurred above the booster/tank forward attachment (below left) and grew in milliseconds to the maximum size indicated in the computer drawing.

51l-s-017-1

51L-S-017 (30 Jan. 1986) --- Wreckage from the space shuttle Challenger, STS-51L mission, retrieved from the Atlantic Ocean by a flotilla of United States Coast Guard and United States Navy vessels was returned to the Trident Basin at Cape Canaveral Air Force Station aboard the USCG Cutter Dallas tonight. Photo credit: NASA

51l-s-024

51L-S-024 (30 Jan. 1986) --- Wreckage from the space shuttle Challenger, STS-51L mission, retrieved from the Atlantic Ocean by a flotilla of United States Coast Guard (USCG) and United States Navy (USN) vessels was returned to the Trident Basin at Cape Canaveral Air Force Station aboard the USCG Cutter Dallas tonight. Photo credit: NASA

---

Report of the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident Chapter III: The Accident

[19] Flight of the Space Shuttle Challenger on Mission 51-L began at 11:38 a.m. Eastern Standard Time on January 28, 1986. It ended 73 seconds later in an explosive burn of hydrogen and oxygen propellants that destroyed the External Tank and exposed the Orbiter to severe aerodynamic loads that caused complete structural breakup. All seven crew members perished. The two Solid Rocket Boosters flew out of the fireball and were destroyed by the Air Force range safety officer 110 seconds after launch.

The ambient air temperature at launch was 36 degrees Fahrenheit measured at ground level approximately 1,000 feet from the 51-L mission launch pad 39B. This temperature was 15 degrees colder than that of any previous launch.

The following description of the flight events is based on visual examination and image enhancement of film from NASA operated cameras and telemetry data transmitted from the Space Shuttle to ground stations. The last telemetry data from the Challenger was received 73.618 seconds after launch.

At 6.6 seconds before launch, the Challenger's liquid fueled main engines were ignited in sequence and run up to full thrust while the entire Shuttle structure was bolted to the launch pad. Thrust of the main engines bends the Shuttle assembly forward from the bolts anchoring it to the pad. When the Shuttle assembly springs back to the vertical, the Solid Rocket Boosters' restraining bolts are explosively released. During this prerelease "twang" motion, structural loads are stored in the assembled structure. These loads are released during the first few seconds of flight in a structural vibration mode at a frequency of about 3 cycles per second. The maximum structural loads on the aft field joints of the Solid Rocket Boosters occur during the "twang," exceeding even those of the maximum dynamic pressure period experienced later in flight.

Just after liftoff at .678 seconds into the flight, photographic data show a strong puff of gray smoke was spurting from the vicinity of the aft field joint on the right Solid Rocket Booster. The two pad 39B cameras that would have recorded the precise location of the puff were inoperative. Computer graphic analysis of film from other cameras indicated the initial smoke came from the 270 to 310-degree sector of the circumference of the aft field joint of the right Solid Rocket Booster. This area of the solid booster faces the External Tank. The vaporized material streaming from the joint indicated there was not complete sealing action within the joint.

Eight more distinctive puffs of increasingly blacker smoke were recorded between .836 and 2.500 seconds. The smoke appeared to puff upwards from the joint. While each smoke puff was being left behind by the upward flight of the Shuttle, the next fresh puff could be seen near the level of the joint. The multiple smoke puffs in this sequence occurred at about four times per second, approximating the frequency of the structural load dynamics and resultant joint flexing. Computer graphics applied to NASA photos from a variety of cameras in this sequence again placed the smoke puffs' origin in the 270-to 310-degree sector of the original smoke spurt.

As the Shuttle increased its upward velocity, it flew past the emerging and expanding smoke puffs. The last smoke was seen above the field joint at 2.733 seconds. At 3.375 seconds the last [20] smoke was visible below the Solid Rocket Boosters and became indiscernible as it mixed with rocket plumes and surrounding atmosphere.

The black color and dense composition of the smoke puffs suggest that the grease, joint insulation and rubber O-rings in the joint seal were being burned and eroded by the hot propellant gases.

file:///C|/...20Chart%20V-2/Interactive%20Sig%20Inc%20Prototype/Space%20Shuttle/STS-51L/Chapter%20III-%20The%20Accident.htm[1/28/2015 10:57:43 AM]

v1ch3

Launch sequence films from previous missions were examined in detail to determine if there were any prior indications of smoke of the color and composition that appeared during the first few seconds of the 51-L mission. None were found. Other vapors in this area were determined to be melting frost from the bottom of the External Tank or steam from the rocket exhaust in the pad's sound suppression water trays.

Shuttle main engines were throttled up to 104 percent of their rated thrust level, the Challenger executed a programmed roll maneuver and the engines were throttled back to 94 percent.

At approximately 37 seconds, Challenger encountered the first of several high-altitude wind shear conditions, which lasted until about 64 seconds. The wind shear created forces on the vehicle with relatively large fluctuations. These were immediately sensed and countered by the guidance, navigation and control system. Although flight 51-L loads exceeded prior experience in both yaw and pitch planes at certain instants, the maxima had been encountered on previous flights and were within design limits.

The steering system (thrust vector control) of the Solid Rocket Booster responded to all commands and wind shear effects. The wind shear caused the steering system to be more active than on any previous flight.

At 45 seconds into the flight, three bright flashes appeared downstream of the Challenger's right wing. Each flash lasted less than one-thirtieth of' a second. Similar flashes have been seen on other flights. Another appearance of a separate bright spot was diagnosed by film analysis to be a reflection of main engine exhaust on the Orbital Maneuvering System pods located at the upper rear section of the Orbiter. The flashes were unrelated to the later appearance of the flame plume from the right Solid Rocket Booster.

Both the Shuttle main engines and the solid rockets operated at reduced thrust approaching and passing through the area of maximum dynamic pressure of 720 pounds per square foot. Main engines had been throttled up to 104 percent thrust and the Solid Rocket Boosters were increasing their thrust when the first flickering flame appeared on the right Solid Rocket Booster in the area of the aft field joint. This first very small flame was detected on image enhanced film at 58.788 seconds into the flight. It appeared to originate at about 305 degrees around the booster circumference at or near the aft field joint.

One film frame later from the same camera, the flame was visible without image enhancement. It grew into a continuous, well-defined plume at 59.262 seconds. At about the same time (60 seconds), telemetry showed a pressure differential between the chamber pressures in the right and left boosters. The right booster chamber pressure was lower, confirming the growing leak in the area of the field joint.

As the flame plume increased in size, it was deflected rearward by the aerodynamic slipstream and circumferentially by the protruding structure of the upper ring attaching the booster to the External Tank. These deflections directed the flame plume onto the surface of the External Tank. This sequence of flame spreading is confirmed by analysis of the recovered wreckage. The growing flame also impinged on the strut attaching the Solid Rocket Booster to the External Tank.

At about 62 seconds into the flight, the control system began to react to counter the forces caused by the plume and its effects. The left Solid Rocket Booster thrust vector control moved to counter the yaw caused by reduced thrust from the leaking right Solid Rocket Booster. During the next nine seconds, Space Shuttle control systems worked to correct anomalies in pitch and yaw rates.

The first visual indication that swirling flame from the right Solid Rocket Booster breached the External Tank was at 64.660 seconds when there was an abrupt change in the shape and color of the plume. This indicated that it was mixing with leaking hydrogen from the External Tank. Telemetered changes in the hydrogen tank pressurization confirmed the leak. Within 45 milliseconds of the breach of the External Tank, a bright sustained glow developed on the black-tiled underside of the Challenger between it and the External Tank.

Beginning at about 72 seconds, a series of events occurred extremely rapidly that terminated [21] the flight. Telemetered data indicate a wide variety of flight system actions that support the visual evidence of the photos as the Shuttle struggled futilely against the forces that were destroying it.

file:///C|/...20Chart%20V-2/Interactive%20Sig%20Inc%20Prototype/Space%20Shuttle/STS-51L/Chapter%20III-%20The%20Accident.htm[1/28/2015 10:57:43 AM]

v1ch3

At about 72.20 seconds the lower strut linking the Solid Rocket Booster and the External Tank was severed or pulled away from the weakened hydrogen tank permitting the right Solid Rocket Booster to rotate around the upper attachment strut. This rotation is indicated by divergent yaw and pitch rates between the left and right Solid Rocket Boosters.

At 73.124 seconds, a circumferential white vapor pattern was observed blooming from the side of the External Tank bottom dome. This was the beginning of the structural failure of the hydrogen tank that culminated in the entire aft dome dropping away. This released massive amounts of liquid hydrogen from the tank and created a sudden forward thrust of about 2.~3 million pounds, pushing the hydrogen tank upward into the intertank structure. At about the same time, the rotating right Solid Rocket Booster impacted the intertank structure and the lower part of the liquid oxygen tank. These structures failed at 73.137 seconds as evidenced by the white vapors appearing in the intertank region.

Within milliseconds there was massive, almost explosive, burning of the hydrogen streaming from the failed tank bottom and the liquid oxygen breach in the area of the intertank.

At this point in its trajectory, while traveling at a Mach number of 1.92 at an altitude of 46,O00 feet, the Challenger was totally enveloped in the explosive burn. The Challenger's reaction control system ruptured and a hypergolic burn of its propellants occurred as it exited the oxygen-hydrogen flames. The reddish brown colors of the hypergolic fuel burn are visible on the edge of the main fireball. The Orbiter, under severe aerodynamic loads, broke into several large sections which emerged from the fireball. Separate sections that can be identified on film include the main engine/tail section with the engines still burning, one wing of the Orbiter, and the forward fuselage trailing a mass of umbilical lines pulled loose from the payload bay.

Evidence in the recovered wreckage from the 51-L mission hardware supports this final sequence of events.

[22-23] Immediately after solid rocket motor ignition, dark smoke (arrows) swirled out between the right hand booster and the External Tank. The smoke's origin, behavior and duration was approximated by visual analysis and computer enhancement of film from five camera locations. Consensus: smoke was first discernible at .678 seconds Mission Elapsed Time in the vicinity of the right booster's aft field joint.

[24-25] Multiple smoke puffs are visible in the photo above (arrows). They began at .836 seconds and continued through 2.500 seconds, occurring about 4 times a second. Upward motion of the vehicle caused the smoke to drift downward and blur into a single cloud. Smoke source is shown in the computer generated drawing (far right).

[26-27]

file:///C|/...20Chart%20V-2/Interactive%20Sig%20Inc%20Prototype/Space%20Shuttle/STS-51L/Chapter%20III-%20The%20Accident.htm[1/28/2015 10:57:43 AM]

v1ch3

At 58.788 seconds, the first flicker of flame appeared. Barely visible above, it grew into a large plume and began to impinge on the External Tank at about 60 seconds. Flame is pinpointed in the computer drawing between the right booster and the tank, as in the case of earlier smoke puffs. At far right (arrow), vapor is seen escaping from the apparently breached External Tank.

[28-29]

Camera views indicate the beginning of rupture of the liquid hydrogen and liquid oxygen tanks within the External Tank. A small flash (arrows above) intensified rapidly, then diminished. A second flash, attributed to rupture of the liquid oxygen tank, occurred above the booster/tank forward attachment (below left) and grew in milliseconds to the maximum size indicated in the computer drawing.

[30-31] Structural breakup of the vehicle began at approximately 73 seconds. Fire spread very rapidly. Above [left], a bright flash (arrow) is evident near the nose the Orbiter, suggesting spillage and ignition of the spacecraft's reaction control system propellants. At left, the two Solid Rocket Boosters thrust away from the fire, crisscrossing to from a "V". The right booster- identifiable by its failure plume- now to the left of its counterpart. At right, the boosters diverge farther; the External Tank wreckage is obscured by smoke and vapor. The Orbiter engines still firing, is visible at bottom center.

[32-33] At about 76 seconds, unidentifiable fragments of the Shuttle vehicle can be seen tumbling against a background of fire, smoke and vaporized propellants from the External Tank (left). In the photo at right, the left booster (far right) soars away, still thrusting. The reddish-brown cloud envelops the disintegrating Orbiter. The color is characteristic of the nitrogen tetroxide oxidizer in the Orbiter Reaction Control System propellant.

file:///C|/...20Chart%20V-2/Interactive%20Sig%20Inc%20Prototype/Space%20Shuttle/STS-51L/Chapter%20III-%20The%20Accident.htm[1/28/2015 10:57:43 AM]

v1ch3

Hurtling out of the fireball at 78 seconds (left) are the Orbiter's left wing (top arrow), the main engines (center arrow) and the forward fuselage (bottom arrow). In the photo below [bottom right], it plummets Earthward, trailed by smoking fragments of Challenger

[36]

At 11:44 a.m. Eastern Standard Time, a GOES environment-monitoring satellite operated by the National Oceanic and Atmospheric Administration acquired this image of the smoke and vapor cloud from the 51-L accident. The coast of Florida is outlined in red.

[37-39] STS 51-L Sequence of Major Events

[34-35]

.

Mission Time (GMT, in hr:min:sec)

Event

Elapsed Time (secs.)

Source

16:37:53.444

ME - 3 Ignition Command

- 6.566

GPC

37:53.564

ME - 2 Ignition Command

- 6.446

GPC

37:53.684

ME - 1 Ignition Command

- 6.326

GPC

38:00.010

SRM Ignition Command (T=O)

0.000

GPC

38:00.018

Holddown Post 2 PIC firing

0.008

E8 Camera

38:00.260

First Continuous Vertical Motion

0.250

E9 Camera

38:00.688

Confirmed smoke above field joint on RH SRM

0.678

E60 Camera

38:00.846

Eight puffs of smoke (from 0.836 thru 2.500 sec MET)

0.836

E63 Camera

38:02.743

Last positive evidence of smoke above right aft SRB/ET attach ring

2.733

CZR-1 Camera

38:03.385

Last positive visual indication of smoke

3.375

E60 Camera

38:04.349

SSME 104% Command

4.339

E41M2076D

38:05.684

RH SRM pressure 11.8 psi above nominal

5.674

B47P2302C

38:07.734

Roll maneuver initiated

7.724

V9OR5301C

38:19.869

SSME 94% Command

19.859

E41M2076D

38:21.134

Roll maneuver completed

21.124

V9OR5301C

38:35.389

SSME 65% Command

35.379

E41M2076D

file:///C|/...20Chart%20V-2/Interactive%20Sig%20Inc%20Prototype/Space%20Shuttle/STS-51L/Chapter%20III-%20The%20Accident.htm[1/28/2015 10:57:43 AM]

v1ch3

 

38:37.000 Roll and Yaw Attitude Response to Wind (36.990 to 62.990 sec) 36.990 V95H352nC

 

38:51.870 SSME 104% Command 51.860 E41M2076D

38:58.798 First evidence of flame on RH SRM 58.788 E207 Camera

38:59.010 Reconstructed Max Q (720 psf) 59.000 BET

38:59.272 Continuous well defined plume on RH SRM 59.262 E207 Camera

38: 59.763 Flame from RH SRM in + Z direction (seen from south side of vehicle) 59.753 E204 Camera

39:00.014 SRM pressure divergence (RH vs. LH) 60.004 B47P2302

39:00.248 First evidence of plume deflection, intermittent 60.238 E207 Camera

39:00.258 First evidence of SRB plume attaching to ET ring frame 60.248 E203 Camera

39:00.998 First evidence of plume deflection, continuous 60.988 E207 Camera

39:01.734 Peak roll rate response to wind 61.724 V9OR5301C

39:02.094 Peak TVC response to wind 62.084 B58H1150C

39:02.414 Peak yaw rate response to wind 62.404 V9OR5341C

39:02.494 RH outboard elevon actuator hinge moment spike 62.484 V58P0966C

39:03.934 RH outboard elevon actuator delta pressure change 63.924 V58P0966C

39:03.974 Start of planned pitch rate maneuver 63.964 V9OR5321C

39:04.670 Change in anomalous plume shape (LH2 tank leak near 2058 ring frame) 64.660 E204 Camera

39:04.715 Bright sustained glow on sides of ET 64.705 E204 Camera

39:04.947 Start SSME gimbal angle large pitch variations 64.937 V58HllOOA

39:05.174 Beginning of transient motion due to changes in aero forces due to plume 65.164 V9OR5321C

39:05.534 LH outboard elevon actuator delta pressure change 65.524 V58P0866C

39:06.774 Start ET LH2 ullage pressure deviations 66.764 T41P1700C

39:12.214 Start divergent yaw rates (RH vs. LH SRB) 72.204 V9OR2528C

39:12.294 Start divergent pitch rates (RH vs. LH SRB) 72.284 V9OR2525C

39:12.488 SRB major high-rate actuator command 72.478 V79H2111A

39:12.507 SSME roll gimbal rates 5 deg/sec 72.497 V58HllOOA

39:12.535 Vehicle max + Y lateral acceleration ( + .227 g) 72.525 V98A1581C

39:12.574 SRB major high-rate actuator motion 72.564 B58H1151C

39:12.574 Start of H2 tank pressure decrease with 2 flow control valves open 72.564 T41P1700C

39:12.634 Last state vector downlinked 72.624 Data reduction

39:12.974 Start of sharp MPS LOX inlet pressure drop 72.964 V41P1330C

39:13.020 Last full computer frame of TDRS data 73.010 Data reduction

39:13.054 Start of sharp MPS LH2 inlet pressure drop 73.044 V41Pl lOOC

39:13.055 Vehicle max -Y lateral acceleration (-.254 g) 73.045 V98A1581C

39:13.134 Circumferential white pattern on ET aft dome (LH2 tank failure) 73.124 E204 Camera

39:13.134 RH SRM pressure 19 psi lower than LH SRM 73.124 B47P2302C

39:13.147 First hint of vapor at intertank 73.137 E207 Camera

39:13.153 All engine systems start responding to loss of fuel and LOX inlet pressure 73.143 SSME team

39:13.172 Sudden cloud along ET between intertank and aft dome 73.162 E207 Camera

39:13.201 Flash between Orbiter and LH2 tank 73.191 E204 Camera

39:13.221 SSME telemetry data interference from 73.211 to 73.303 73.211 .

39:13.223 Flash near SRB fwd attach and brightening of flash between Orbiter and ET 73.213 E204 Camera

39:13.292 First indication intense white flash at SRB fwd attach point 73.282 E204 Camera

39:13.337 Greatly increased intensity of white flash 73.327 E204 Camera

39:13.387 Start RCS jet chamber pressure fluctuations 73.377 V42P1552A

39:13.393 All engines approaching HPFT discharge temp redline limits 73.383 E41TnO1OD

39:13.492 ME-2 HPFT disch. temp Chan. A vote for shutdown; 2 strikes on Chan. B 73.482 MEC data

39:13.492 ME-2 controller last time word update 73.482 MEC data

Quelle: NASA
 
 
770 Views