{"id":40541,"date":"2011-01-29T00:42:07","date_gmt":"2011-01-28T16:42:07","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/1983-1986-the-missions-and-history-of-space-shuttle-challenger\/"},"modified":"2011-01-29T00:42:07","modified_gmt":"2011-01-28T16:42:07","slug":"1983-1986-the-missions-and-history-of-space-shuttle-challenger","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/1983-1986-the-missions-and-history-of-space-shuttle-challenger\/","title":{"rendered":"1983-1986: The Missions and History of Space Shuttle Challenger"},"content":{"rendered":"

25-years ago today, Space Shuttle Challenger was lost with all hands in the bright blue sky over Central Florida. Embarking on her 10th mission on January 28, 1986, Challenger was at the time the most-flown orbiter in NASA\u2019s fleet. Quickly rising to prominence as the fleet leader (in terms of not only the number of missions flown, but also her impressive scientific and technological accomplishments), Challenger was the workhorse of the early days of the Shuttle fleet, setting numerous records and leaving behind a legacy of education, inspiration, and safety.<\/p>\n

The History of Space Shuttle Challenger:<\/p>\n

The early history of Challenger is arguable the most complex of the six Shuttle orbiters (Enterprise, Columbia, Challenger, Discovery, Atlantis, and Endeavour) constructed by NASA in the 1970s, 80s, and 90s.<\/p>\n

Beginning life as STA-099 (Structural Test Article -099), the components that would eventually become the airframe and body for orbiter Challenger were initially used by the Space Shuttle Program (SSP) to test and validate the effects of launch and entry stress (including heating) on a \u201clight weight\u201d Shuttle airframe \u2013 a weight reduction savings that would, in turn, allow future orbiters (from Challenger through Endeavour) to have a greater payload weight to orbit capability than pioneer orbiter and older sister Columbia.<\/p>\n

Since computer technology in the 1970s was not powerful or advanced enough to accurately calculate\/predict the effects a \u201clight weight\u201d airframe would have on an orbiter\u2019s performance and ability during launch and entry ops, NASA opted to build STA-099 and submit the Structural Test Article to a year of intense vibration and thermal testing.<\/p>\n

To this end, the contract to begin construction of STA-099 was awarded on July 26, 1972 to Rockwell International. For the next three years, components for STA-099 were manufactured simultaneously with components for what would eventually become orbiter Columbia.<\/p>\n

\"\"On November 21, 1975, engineers began structural assembly of STA-099\u2019s crew module. This was followed on June 14, 1976 by the start of structural assembly of the aft-fuselage.<\/p>\n

STA-099\u2019s tell-tale Delta wings arrived on-dock at the Palmdale, California construction facility on March 16, 1977.<\/p>\n

Final assembly began later that year on September 30 and was completed on February 10, 1978. STA-099 rolled out of Palmdale on February 14 (Valentine\u2019s Day), 1978.<\/p>\n

For the next year, STA-099 was put through the wringer, with numerous vibration and thermal tests to provide and ground the light weight airframe design planned for future Shuttle orbiters.<\/p>\n

As stated by Volume II of the NASA Engineering and Safety Center Technical Report from June 14, 2007, \u201cThere was a high probability that performing static strength tests to demonstrate ultimate design limits (1.4 times limit load) would result in deformations and strains that [would] render the vehicle unusable for flight.\u201d<\/p>\n

Nonetheless, \u201cit was clear the vehicle must be shown to be acceptable at the design limit loads [ref. 19].\u201d<\/p>\n

To this end, \u201ca hybrid qualification program was adopted that combined limited flight hardware testing and the validation of stress predictions through the modeling and testing of prototype hardware assemblies and components. \u201cQualification\u201d tests on STA-099 were performed at 1.2 times the design limit loads.\u201d<\/p>\n

Meanwhile, Rockwell was busy finishing the final year of assembly of orbiter Columbia (OV-102) at Palmdale, and NASA was busy reviewing the wealth of data gathered from orbiter Enterprise\u2019s (OV-101\u2019s) free-flight approach and landing tests in 1977 while taking Enterprise through KSC mating, rollout, and launch pad validation ops.<\/p>\n

But behind all this, discussions were beginning to focus on the cost and time that would be required to convert Enterprise into a space-worthy vehicle. As the costs and timelines began to build, NASA realized that it would cost less, and take less time, to convert STA-099 into a space-worthy vehicle than it would Enterprise.<\/p>\n

\"\"On January 1, 1979, the decision was made official when NASA awarded Rockwell International the contract to convert STA-099 into OV-099 (Orbital Vehicle -099). While the process of converting STA-099 into OV-099 was simpler than converting Enterprise, it still involved intensive work and the disassembly and reconstruction of numerous air frame and flight elements.<\/p>\n

With conversion of STA-099 into OV-099, the process began of selecting a name for the now-second orbiter of the Shuttle fleet.<\/p>\n

Named after the HMS Challenger \u2013 a British corvette which served as the command ship for the Challenger Expedition (a pioneering global marine research expedition from 1872-1876) \u2013 and the Apollo 17 lunar module, Challenger is the only Shuttle orbiter to be named in honor of a previously-flown spacecraft that landed on the surface of another celestial body.<\/p>\n

In an odd coincidence, crews began the start of structural assembly of Challenger\u2019s flight-worthy crew module on January 28, 1979 \u2013 exactly 7 years to the day before she would be lost.<\/p>\n

From this point, through Nov. 3, 1980, engineers and technicians disassembled and rebuilt Challenger. On Nov. 3, final assembly began and ran through October 21, 1981.<\/p>\n

\"\"Workers spent the next year going over Challenger with a fine-toothed comb and completing installation of the vehicle\u2019s Thermal Protection System (TPS) tiles and RCC (Reinforced Carbon-Carbon) WLE (Wing Leading Edge) and nose cap panels.<\/p>\n

A major change between the construction of Columbia and Challenger was the replacement of TPS tiles with DuPont white nomex felt insulation on her payload bay doors, upper wing surfaces, and rear fuselage. This move further reduced Challenger\u2019s weight by 2,500 lbs.<\/p>\n

On June 30, 1982, Challenger rolled out of her Palmdale assembly facility. She was transported overland to Edwards Air Force Base the following day where she spent four days being mated to the Shuttle Carrier Aircraft for her ferry flight delivery to the Kennedy Space Center.<\/p>\n

On the day of the beginning of the ferry flight, sister orbiter Columbia triumphantly returned to Earth on July 4 with an Independence Day landing at Edwards Air Force Base to cap off STS-4 and the orbital test flight phase of the Shuttle Program.<\/p>\n

With Columbia on the runway at Edwards, Challenger and the SCA took off on July 4 under the watchful eye of then-U.S. President Ronald Reagan. One day later, Challenger arrived at the Kennedy Space Center.<\/p>\n

\"\"One day after delivery, Challenger was towed into an OPF (Orbiter Processing Facility), where she underwent initial receiving inspections before being transitioned into pre-mission processing for her maiden flight.<\/p>\n

Challenger spent nearly 4 months in the OPF before she was moved to the VAB on Nov. 23 for mating with her External Tank\/Solid Rocket Booster (ET\/SRB) stack. Seven days later, on November 30, 1982, Challenger and the STS-6 stack was rolled out to LC-39A to undergo both pad processing and the mandatory Flight Readiness Firing (FRF) before a targeted January 20, 1983 launch.<\/p>\n

On December 18, 1982, the customary 20-second FRF occurred, revealing a hydrogen leak into SSME-1 (Space Shuttle Main Engine 1). Launch was postponed from January 20 and a second FRF was performed on January 25.<\/p>\n

The second FRF confirmed the presence of cracks in SSME-1. To the end, all three SSMEs were removed while Challenger was at Pad-A. This marked the first time in Shuttle Program history that the SSMEs were removed at the launch pad.<\/p>\n

The second FRF for Challenger also places her in the record books for being the only Shuttle orbiter to require two FRFs before her maiden flight. However, Challenger is not the only orbiter to have two FRFs to her name. Discovery underwent a second FRF during the Return to Flight launch campaign for STS-26 \u2013 the mission which returned the Shuttle fleet to flight following the loss of Challenger.<\/p>\n

With the removal of all three of Challenger\u2019s SSMEs, the teams thoroughly tested and analyzed SSMEs 2 and 3 before reinstalling them for flight. SSME-1 was completely replaced.<\/p>\n

The launch date was then reset before being pushed back yet again due to the contamination of Challenger\u2019s payload \u2013 the first Tracking and Data Relay Satellite (TDRS-1) \u2013 during a severe storm at the launch pad.<\/p>\n

\"\"Once the contamination issue was fixed, the launch was rescheduled for April 4 at 1330 EST. The countdown proceeded on schedule and Challenger lifted off on her maiden voyage right on time on April 4, 1983. <\/p>\n

Weighing 256,744lbs at launch, Challenger ushered in a series of firsts for the Shuttle Program STS-6. The maiden flight of Challenger marked the first flight of a Space Shuttle from the new MLP-2 (Mobile Launch Platform 2), the first Shuttle flight to use the Light Weight External Tank, the first flight of new light weight SRB casings, the first afternoon launch of a Space Shuttle, and the first time that a second reusable spacecraft flew into space.<\/p>\n

On STS-6, Challenger carried Story Musgrave into space \u2013 the only person who would go to fly on all five space-worthy Space Shuttle orbiters.<\/p>\n

STS-6 also marked the last time that a Space Shuttle mission would launch with a crew of only four astronauts. (However, if STS-135\/Atlantis does indeed become a reality, STS-135 will mark the first time since STS-6 that a Shuttle will launch with only four people onboard.)<\/p>\n

\"\"Launched into a 28.5 degree 178nm orbit, Challenger\u2019s crew successfully deployed the TDRS-1 satellite from the vehicle\u2019s payload bay. A malfunction of TDRS-1\u2019s Inertial Upper Stage (IUS) initially placed the satellite into an improper but stable orbit. Reserve propellant was used to boost TDRS-1 into its properly circularized orbit over the following months.<\/p>\n

Following the deployment of TDRS-1, the Challenger crew turned their attention to performing the Shuttle Program\u2019s first spacewalk, or EVA. Lasting 4 hours 17 minutes, Mission Specialists Story Musgrave and Donald Peterson tested the Shuttle Program\u2019s spacesuits, or EMUs, and demonstrated their ability to perform necessary tasks in a microgravity environment.<\/p>\n

After 81 orbits of Earth and 2,094,293 miles, Challenger touched down on Runway 22 at Edwards Air Force Base, CA on April 9 at 10:53:42 PST, bringing her total mission duration for her maiden flight to 5 days 2 hours 14 minutes and 25 seconds.<\/p>\n

Challenger then underwent initial post-flight deservicing at Edwards before returning to KSC on the SCA on April 16. She was towed into an OPF on April 17 to undergo post-flight deservicing and pre-flight mission processing for STS-7.<\/p>\n

After just over a month in the OPF, Challenger was rolled over to the VAB on May 21 and mated to her ET\/SRB stack for STS-7. The entire stack was rolled out to LC-39A on May 26 for a targeted June 18 launch.<\/p>\n

\"\"Pad processing and the launch countdown proceeded nominal and Challenger lifted off right on time (with no launch delays) on her second flight at 07:33 EDT 18 June 1983. Launch of Challenger on STS-7 marked the first flight of an American woman in space and the first re-flight of an astronaut on the Space Shuttle \u2013 with Robert L. Crippen from STS-1 commanding Challenger\u2019s second flight.<\/p>\n

Launched into a 28.5 degree 160-170nm orbit, Challenger deployed two communications satellites (ANIK C-2 for Canada and PALAPA-B2) for Indonesia.<\/p>\n

Seven Get Away Special canisters were also launched in Challenger\u2019s payload bay, as well as an experiment studying the effects of space on the social behavior of an ant colony. Ten experiments were also mounted on Shuttle Pallet Satellite (SPAS-01), experiments designed to perform research in forming metal alloys in microgravity and the use of remote sensing scanners.<\/p>\n

During the flight, Challenger\u2019s crew fired the vehicle\u2019s RCS control thrusters while SPAS-01 was held by SRMS (Shuttle Remote Manipulator System) to test the forces of the RCS firings on the extended arm.<\/p>\n

STS-7 also marked the first time that a Shuttle orbiter\u2019s Ku-Band antenna was used to transmit data through the TDRS network to a ground terminal.<\/p>\n

\"\"STS-7 also holds the distinction of being the first Shuttle flight to carry a planned EOM (End of Mission) landing at the Kennedy Space Center; however, poor weather conditions at Kennedy precluded a landing of Challenger at the Florida spaceport.<\/p>\n

The mission was extended by two orbits to help facilitate a landing at Edwards. Challenger successfully touched down on Runway 15 at Edwards at 06:56.59 PDT on June 24. Rollout distance was 10,450 feet over 75 seconds. Challenger was returned to the Kennedy Space Center on June 29 to begin processing for STS-8.<\/p>\n

Challenger then spent June 30 \u2013 July 26 inside an OPF before rolling to the VAB for mating with the STS-8 SRB\/ET stack. The entire vehicle was then rolled out to Pad-A on August 2 for an August 30 launch.<\/p>\n

Initially, STS-8 had carried a July 1983 launch date for a 3-day 4-person mission to deploy the TDRS-B satellite. However, because of IUS issues during the deployment of TDRS-1, the flight was remanifested and TDRS-B pulled from the flight. (TDRS-B would later be remanifested for launch on Challenger\u2019s STS-51E flight before additional problems with the satellite pushed its launch to the fateful STS-51L\/Challenger mission.)<\/p>\n

\"\"Pad processing for STS-8 was uneventful. In the early evening\/night hours of Aug. 29\/30, a large thunderstorm complex rolled over the Kennedy Space Center during the final few hours of the STS-8 countdown \u2013 providing a spectacular image of  lightening arcing around Challenger as she sat on Pad-A.<\/p>\n

Due to the inclement weather, launch was delayed 17 minutes. At 02:32 EDT, Challenger lit up the night sky of Florida, embarking on her third flight.<\/p>\n

Launch of Challenger on STS-8 marked the first night time launch of the Space Shuttle, the 20th overall mission to launch from pad 39A, and the first flight of an African-American into space.<\/p>\n

\"\"This would also become the first flight for which concern over potential catastrophic failure of the SRBs during flight would begin to build following discovery of SRB flight malfunction during post-flight casing inspections.<\/p>\n

With a liftoff weight of 242,742 lbs, Challenger was inserted into 28.5 degree 191nm orbit.  Over the course of the six day mission, Challenger\u2019s crew deployed INSAT-1B for India and pointed the nose of Challenger away from the sun for a total of 14 hours to test the vehicle\u2019s flight deck in extreme cold conditions.<\/p>\n

During STS-8, Challenger\u2019s orbit was lowered to 139nm to perform tests on thin atomic oxygen in an effort to understand the cause of a glow that had been observed to surround the orbiter during nighttime orbital passes.<\/p>\n

\"\"Challenger\u2019s SRMS was tested again on this mission to evaluate joint reactions to higher loads. Ku-Band testing\/communication with TDRS-1 also continued on this flight to validate the system\u2019s com connections before STS-9 made heavy use of TDRS-1.<\/p>\n

Challenger also carried and tested equipment to allow for encrypted communications on future DoD (Department of Defense) dedicated and classified missions.<\/p>\n

After 6 days 1 hour 8 minutes and 43 seconds, Challenger glided to a darkened Runway 22 at Edwards at 00:43:43 PDT on September 5 \u2013 thereby performing the first night time landing for the Space Shuttle Program.<\/p>\n

Challenger was returned to the Kennedy Space Center on September 9 and moved into an OPF the following day. This time, Challenger spent four months in the OPF undergoing processing for the STS-41B flight. Just prior to OPF rollout, all three of Challenger\u2019s Auxiliary Power Units (APUs) were removed and replaced (R&Red) as a precautionary measure following APU failures on Columbia\u2019s STS-9 mission.  As a result, the launch date for this mission was postponed from Jan. 29 to February 3.<\/p>\n

On January 6, 1984, Challenger was finally rolled to the VAB. Six days later, the STS-41B stack was rolled out to Pad-A where processing occurred with just a few minor issues\/hiccups.<\/p>\n

\"\"Challenger lifted off right on time at 08:00 EST on February 3 on her fourth launch to begin the 10th Space Shuttle mission and the first under the new flight classification system. Had the previous numerical designation continued, this would have been the STS-11 mission.<\/p>\n

(Incidentally, Challenger would be the first Shuttle orbiter to launch under the new classification system as well as the last orbiter to do so. NASA would revert back to the straight up numerical flight designation system following the loss of Challenger on STS-51L.)<\/p>\n

Like her three previous missions, Challenger was inserted into a 28.5 degree 189nm orbit. Once in orbit, Challenger\u2019s crew deployed the WESTAR-VI and PALAPA-B2 satellites and Bruce McCandless and Robert L. Stewart performed the first untethered EVA in history using the Manned Maneuvering Unit (McCandless) and the SRMS foot restraint for EVA purposes (Stewart). During this EVA, McCandless became the first human Earth-orbiting satellite when he ventured 320 feet away from Challenger.<\/p>\n

Also carried aboard Challenger on this flight was the German-built Shuttle Pallet Satellite \u2013 which became the first satellite to be refurbished and re-flown into space following its first flight on STS-7. An electrical problem with SRMS, however, precluded the deployment of the satellite as intended.<\/p>\n

After 7 days 23 hours 15 minutes and 55 seconds, Challenger triumphantly reentered Earth\u2019s atmosphere to conduct the first EOM landing of a Space Shuttle at the Kennedy Space Center. Landing occurred on February 11 at 07:15:55 EST on KSC Runway 15. Rollout distance was 10,815 feet over 67 seconds.<\/p>\n

\"\"Challenger was returned to the OPF later that day where she spent just over a month in pre-flight processing for STS-41C.  On March 14, she was moved to the VAB. The STS-41C stack was rolled out to Pad-A on March 19 ahead of an April 6 launch.<\/p>\n

Pad processing once again proceeded without issue, and on April 6, 1984 at 08:58 EST, Challenger lifted off right on time on her first attempt to begin her 5th mission.<\/p>\n

The launch of STS-41C marked the first direct ascent trajectory for the Space Shuttle Program and the mission itself marked the first time that a Shuttle mission was on orbit on the anniversary of the first Space Shuttle flight (April 12).<\/p>\n

Launched into a 28.5 degree 288nm high orbit, Challenger\u2019s crew deployed the Long Duration Exposure Facility into Earth orbit for retrieval on a later Shuttle flight.<\/p>\n

After this, Challenger\u2019s orbit was raised to 313nm so that the crew could rendezvous, grapple, repair, and re-deploy the Solar Max satellite. Initial attempts by Mission Specialist George \u201cPinky\u201d Nelson to manually grapple Solar Max with a special capture tool failed.<\/p>\n

Nelson then tried to physically grab the satellite, but that sent the satellite into a multi-axis spin. In the overnight hours, the Goddard Spaceflight Center was able to regain control of the satellite. With the satellite stable, Challenger\u2019s crew grappled the satellite with the SRMS and the crew turned their attention toward using the Manned Maneuvering Unit \u2013 tested on the previous flight \u2013 to replace the altitude control system and coronagraph\/polarimeter electronics box in the Solar Max satellite. <\/p>\n

The EVA activities were filmed by an IMAX camera in Challenger\u2019s payload bay. The footage eventually became part of the \u201cThe Dream is Alive\u201d documentary.<\/p>\n

Challenger landed successfully on April 13 at 05:38:07 PST on Runway 17 at Edwards and was returned to the Kennedy Space Center on April 18. This would mark the final flight of the Shuttle with a fleet of only two orbiters. The next mission, STS-41D, would mark the addition of sister Discovery to the fleet.<\/p>\n

However, due to lengthy delays with Discovery\u2019s launch, Challenger ended up spending nearly five months in the OPF for STS-41G \u2013 the longest OPF stay for Challenger. On September 8, Challenger rolled to the VAB and out to Pad-A on September 13 ahead of a planned Oct. 5th launch.<\/p>\n

\"\"Remarkably, pad processing and the launch countdown proceeded nominally with no major issues. At 07:03 EDT on October 5, Challenger lifted off into the morning sky on the 13th Space Shuttle flight.<\/p>\n

Unlike all of Challenger\u2019s previous missions, this flight was launched into a 57 degree 218nm orbit. The flight marked the first time a Shuttle carried a crew of seven into space, the first time two women flew into space together (and the first time two women were in space at the same time), the first time a Canadian flew into space, the first time an Australian-born person flew into space, and the first spacewalk to involve a woman.<\/p>\n

During the 8-day flight, Challenger\u2019s crew deployed the Earth Radiation Budget Satellite and, through an EVA, connected Components of Orbital Refueling System \u2013 thereby demonstrating that it was possible to refuel a satellite in orbit. During this EVA, Kathryn Sullivan became the first woman to perform a spacewalk.<\/p>\n

On October 13, Challenger returned to Earth conducting the second landing of the Space Shuttle at the Kennedy Space Center. This flight would go down as Challenger\u2019s longest mission, clocking in at 8 days 5 hours 23 minutes 33 seconds.<\/p>\n

\"\"Challenger was then returned to the OPF where she began processing for STS-51E to deploy the TDRS-B satellite.<\/p>\n

After four months in the OPF, Challenger was rolled over to the VAB on February 10 and then out to Pad-A on February 15.  Initially, pad processing went smoothly until timing issues were encountered with TDRS-B.<\/p>\n

The issues became severe enough that NASA pulled STS-51E from the launch manifest and cancelled the mission.<\/p>\n

Challenger was rolled back from the launch pad on March 4, 1985 and returned to her OPF on March 7. NASA then remanifested Challenger for the STS-51B mission and OPF processing proceeded through April 10.<\/p>\n

Challenger was mated to her STS-51B ET\/SRB stack on April 10 and rolled out to Pad-A on April 15 ahead of a planned April 29 launch \u2013 only 14-days after Challenger arrived at the pad.<\/p>\n

Pad processing proceeded smoothly. On April 29 a launch processing system failure forced a 2 minute 18 second delay to launch. At 12:02:18 EDT Challenger left Pad-A on her 7th flight and the Space Shuttle Program\u2019s 17th.<\/p>\n

\"\"During post-flight inspections of the SRBs for this mission, it was discovered that one of the SRBs suffered from a failure similar to the one that would be experienced on STS-51L.<\/p>\n

Sadly, this was the second serious O-ring issue identified in 2.5 months. During the January 24, 1985 launch of Discovery\/STS-51C, the primary O-rings in both the Right-Hand and Left-Hand SRBs were found to be severely charred. But it was the discovery of the complete burn-through\/penetration of the primary O-ring and heavy charring and degradation of the secondary O-ring in the center field joint of the right STS-51C SRB that caused the greatest concern.<\/p>\n

Investigations into the failure of the O-rings on STS-51C led to the understanding that the cold temperatures at the time of Discovery\u2019s launch significantly reduced the sealing power of the O-rings. The temperature at the time of the 51C launch was 53 degrees F.<\/p>\n

Sadly, both of these O-ring warnings would be ignored, and temperatures at the time of the 51L\/Challenger launch one year later would be nearly 20 degrees colder than during 51C.<\/p>\n

Nonetheless, Challenger successful obtained a 57 degree 222nm orbit for STS-51B, where she performed 15 primary experiments divided into five basic disciplines: materials sciences, life sciences, fluid mechanics, atmospheric physics, and astronomy via the European Spacelab-3 \u2013 flying here for the first time in a fully operational configuration.<\/p>\n

Of the 15 primary experiments, 14 were deemed successful. Challenger landed successfully on May 6 at 09:11:04 PDT at Edwards.<\/p>\n

\"\"After returning to the Kennedy Space Center, Challenger was in an OPF from May 12 \u2013 June 24, before being rolled to the VAB for mating and then out to Pad-A on June 29 ahead of a planned July 12 launch on STS-51F.<\/p>\n

Pad processing proceeded nominally, as did the countdown. On July 12, the Ground Launch Sequencer handed off control of the countdown and Challenger\u2019s critical systems to Challenger\u2019s onboard computers at T-31secs.<\/p>\n

At T-6.6 seconds, with all systems polling \u201cgo,\u201d Challenger\u2019s computers sent the commands to start the SSMEs in a 120-millisecond staggered start sequence beginning with SSME-3.<\/p>\n

All three engines came up and began building up to full thrust.<\/p>\n

At T-3seconds, Challenger\u2019s computers registered a malfunction in SSME-2\u2019s coolant valve and immediately tripped an RSLS (Redundant Set Launch Sequencer) abort. Commands to shut down SSME-2 were transmitted immediately, as were commands to inhibit the launch sequence, safe the SRB pyros, and shutdown SSMEs 3 and 1.<\/p>\n

Thanks to the safety upgrades put in place following the STS-41D\/Disocvery post-SSME start RSLS abort, post-abort safing was conducted in a methodical manner.<\/p>\n

In the following two weeks, Challenger\u2019s SSMEs were replaced at the launch pad and the launch was reset for July 29, 1985.<\/p>\n

\"\"On that day, the launch was delayed 1 hour 37 minutes due to a problem with the table maintenance block update uplink. With that issue resolved, the countdown resumed and Challenger launched at 17:00 EDT on her 8th mission.<\/p>\n

However, 3mins 13secs into the flight, one of two high pressure fuel turbopump turbine discharge temperature sensors for SSME-1 failed, leaving only one sensor active on the engine. Two minutes 12 seconds later, at Mission Elapsed Time 5mins 43secs, the second sensor failed, triggering the immediate shutdown of SSME-1.<\/p>\n

To date, this is the only occurrence of an engine shutdown during launch for the Space Shuttle.<\/p>\n

The shutdown of SSME-1 significantly lowered the thrust profile for Challenger and triggered the only in-flight abort in Shuttle Program history: an Abort To Orbit (ATO) which allowed Challenger and her seven-member crew to reach a lower-than-planned but safe and stable orbit.<\/p>\n

Nonetheless, before Challenger could complete her prolonged ascent (nearly 9mins 45secs in duration due to the lost thrust from SSME-1), an identical high pressure turbopump temperature sensor failure occurred in SSME-2.<\/p>\n

Booster Systems Engineer Jenny M. Howard in Mission Control Houston acted immediately, instructing the crew to inhibit any further automatic SSME shutdowns based on readings from the remaining sensors. This quick action prevented the loss of another engine and a possible abort scenario far more risky or far worse than the already in-progress ATO.<\/p>\n

\"\"When Challenger finally reached orbit, several aspects of the mission were retooled to account for the lower-than-planned orbital altitude.<\/p>\n

The flight\u2019s primary payload was Spacelab-2, with the main mission objectives being the verification of performance of Spacelab systems and the determination of interface capability of the Shuttle orbiter.<\/p>\n

STS-51F marked the first time the European Space Agency\u2019s Instrument Point System was tested in orbit\u2026 with verification of its accuracy to one arc second.<\/p>\n

After 7 days 22 hours 45 minutes and 26 seconds in space, Challenger touched down on Runway 23 at Edwards at 12:45:26 EDT on August 6. She was returned to the Kennedy Space Center on August 11.<\/p>\n

Challenger then spent exactly 2 months in the OPF while processing for STS-61A, before rolling to the VAB on Oct. 12. The STS-61A stack was rolled out to Pad-A on Oct. 16 for an October 30 launch.<\/p>\n

Yet again, pad processing proceeded nominally and Challenger lifted off right on time on her first attempt at 12-noon EST on October 30.<\/p>\n","protected":false},"excerpt":{"rendered":"

25-years ago today, Space Shuttle Challenger was lost with all hands in the bright blue sky over Central Florida. Embarking on her 10th mission on January 28, 1986, Challenger was at the time the most-flown orbiter in NASA\u2019s fleet. Quickly rising to prominence as the fleet leader (in terms of not only the number of […]<\/p>\n","protected":false},"author":1,"featured_media":29573,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[],"class_list":["post-40541","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40541"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=40541"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40541\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/29573"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=40541"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=40541"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=40541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}