Challenger OV-099
Challenger is launched on its first mission, STS-6
OV designation	OV-099
Country	United States
Contract award	January 1, 1979
Named after	HMS Challenger (1858)
Status	Destroyed January 28, 1986
First flight	STS-6 April 4–9, 1983
Last flight	STS-51-L January 28, 1986
Number of missions	10
Time spent in space	0[1]
Number of orbits	995
Distance travelled	25,803,939 mi (41,527,414 km)
Satellites deployed	10

Space Shuttle Challenger (NASA Orbiter Vehicle Designation: OV-099) was NASA's second Space Shuttle orbiter to be put into service, Columbia having been the first. The shuttle was built by Rockwell International's Space Transportation Systems Division in Downey, California. Its maiden flight was on April 4, 1983, and it completed nine missions before breaking apart 73 seconds after the launch of its tenth mission, STS-51-L on January 28, 1986, resulting in the death of all seven crew members. It was the first of two shuttles (the other being Columbia) to be destroyed. The accident led to a two-and-a-half year grounding of the shuttle fleet, with missions resuming in 1988 with the launch of Space Shuttle Discovery on STS-26. Challenger itself was replaced by the Space Shuttle Endeavour, which first launched in May 1992 and was constructed from structural spares that had been ordered by NASA as part of the construction contracts for Discovery and Atlantis.

History [edit]

Challenger was named after HMS Challenger, a British corvette that was the command ship for the Challenger Expedition, a pioneering global marine research expedition undertaken from 1872 through 1876.^[2] The Apollo 17 lunar module that landed on the Moon in 1972 was also named Challenger.^[2]

Construction [edit]

Challenger being prepared in 1985 for its second-to-last flight STS-61-A

Because of the low production of orbiters, the Space Shuttle program decided to build a vehicle as a Structural Test Article, STA-099, that could later be converted to a flight vehicle. The contract for STA-099 was awarded to North American Rockwell on July 26, 1972, and its construction was completed in February 1978.^[3] After STA-099's rollout, it was promptly sent to a Lockheed in Palmdale, where it would spend over 11 months in vibration tests designed to simulate entire shuttle flights, from launch to landing.^[4] In order to prevent damage during structural testing, qualification tests were performed to a factor of safety of 1.2 times the design limit loads. The qualification tests were used to validate computational models, and compliance with the required 1.4 factor of safety was shown by analysis.^[5]

NASA planned to refit the prototype orbiter Enterprise (OV-101), used for flight testing, as the second operational orbiter. However, design changes made during construction of the first orbiter, Columbia (OV-102), would have required extensive rework. Because STA-099's qualification testing prevented damage, NASA found that rebuilding STA-099 as OV-099 would be less expensive than refitting Enterprise. Work on converting STA-099 into Challenger began in January 1979, starting with just the crew module (the pressurized portion of the vehicle) as the rest of the orbiter was still used by Lockheed. STA-099 returned to the Rockwell plant in November 1979, and the original unfinished crew module was replaced with the newly-constructed model. Work continued on the conversion until 1982.^[6]

Challenger (and the orbiters built after it) had fewer tiles in its Thermal Protection System than Columbia, though it still made heavy use of the white-colored LRSI tiles on the cabin and main fuselage compared to the later orbiters. Most of the tiles on the payload bay doors, upper wing surfaces, and rear fuselage surfaces were replaced with DuPont white Nomex felt insulation. These modifications as well as an overall lighter structure allowed Challenger to carry 2,500 lb (1,100 kg) more payload than Columbia. Challenger's fuselage and wings were also stronger than Columbia's despite being lighter.^[7] The hatch and vertical stabilizer tile patterns were also different from that of the other orbiters. Challenger was also the first orbiter to have a head-up display system for use in the descent phase of a mission, and the first to feature Phase I main engines rated for 104% maximum thrust.

Construction milestones (as STA-099) [edit]

Construction milestones (as OV-099) [edit]

Flights and modifications [edit]

After its first flight in April 1983, Challenger quickly became the workhorse of NASA's Space Shuttle fleet, flying far more missions per year than Columbia. In 1983 and 1984, Challenger flew on 85% of all Space Shuttle missions. Even when the orbiters Discovery and Atlantis joined the fleet, Challenger remained in heavy use with three missions a year from 1983 to 1985. Challenger, along with Discovery, was modified at Kennedy Space Center to be able to carry the Centaur-G upper stage in its payload bay. If flight STS-51-L had been successful, Challenger's next mission would have been the deployment of the Ulysses probe with the Centaur to study the polar regions of the Sun.

Challenger's many spaceflight accomplishments included the first American woman, African-American, and Canadian in space; three Spacelab missions; and the first night launch and night landing of a Space Shuttle. Challenger was also the first space shuttle to be destroyed in an accident during a mission. The collected debris of the vessel are currently buried in decommissioned missile silos at Launch Complex 31, Cape Canaveral Air Force Station. From time to time, further pieces of debris from the orbiter wash up on the Florida coast.^[10] When this happens, they are collected and transported to the silos for storage. Because of its early loss, Challenger was the only space shuttle that never wore the NASA "meatball" logo, and also was never modified with the MEDS "glass cockpit". The tail was also never fitted with a drag chute – it was fitted to the remaining orbiters in 1992.

Challenger's rollout from Orbiter Processing Facility (OPF) to the Vehicle Assembly Building (VAB). Photo 1983-8-25 courtesy of NASA.	Challenger while in service as structural test article STA-099.

Mission insignias [edit]

Mission insignia for Challenger flights
STS 6	STS 7	STS 8	STS 41-B	STS 41-C
STS-41-G	STS-51-B	STS-51-F	STS-61-A	STS-51-L

Loss of Challenger [edit]

The crew of the Challenger's final flight.

Space Shuttle Challenger's smoke plume after its in-flight breakup, resulting in its crash and the deaths of all seven crew members.

This section may be too technical for most readers to understand. Please help improve this section to make it understandable to non-experts, without removing the technical details. The talk page may contain suggestions. (March 2013)

Challenger was destroyed as it broke up in mid-flight in the second minute of its tenth mission, on January 28, 1986 at 11:39:13 am Eastern Standard Time.^[11] The breakup was ultimately due to the failure of an O-ring on its right solid-fuel rocket booster (SRB). The O-rings are used to seal the joints between the multiple segments of the SRBs. The failure was due to a variety of factors, including unusually low temperatures prior to liftoff.^[12] The failure allowed a plume of flame to leak out of the SRB and impinge on both the external fuel tank (ET) and the SRB aft attachment strut. This caused both structural failure of the ET, and pivoting of the SRB into the orbiter and ET. Damage near the bottom of the ET resulted in the complete loss of the aft dome of the lower tank and a rapid release of hydrogen, creating a forward thrust of about 2.8 million pounds and pushing the tank up into the intertank structure which connects the liquid hydrogen tank and liquid oxygen tank. This was followed by an almost explosive burning of the hydrogen combined with oxygen leaking from the intertank. Challenger's reaction control system then ruptured, resulting in the burning of its hypergolic propellants. The orbiter, traveling at about Mach 1.92, was forced into an attitude that caused it to endure extreme aerodynamic loads, with the resulting stresses breaking it apart.^[13] All seven crew members were killed.

Crew members [edit]

• Francis R. Scobee – Mission Commander
• Michael J. Smith – Pilot
• Ellison S. Onizuka – Mission Specialist 1
• Judith A. Resnik – Mission Specialist 2
• Ronald E. McNair – Mission Specialist 3
• Christa McAuliffe – Payload Specialist 1
• Gregory B. Jarvis – Payload Specialist 2

See also [edit]

	Spaceflight portal
	space portal

• List of human spaceflights
• List of Space Shuttle crews
• List of Space Shuttle missions
• Timeline of Space Shuttle missions
• List of human spaceflights chronologically
• Challenger flag

References [edit]

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

Further reading [edit]

• Evans, Ben (2007). Space shuttle challenger: ten journeys into the unknown. Published in association with Praxis Pub. ISBN 978-0-387-46355-1 

External links [edit]

Wikimedia Commons has media related to: Space Shuttle Challenger

• Mission Summary Archive
• Ronald Reagan: Address to the Nation on the Explosion of the Space Shuttle Challenger
• Space Shuttle Challenger Explosion video
• Shuttle Orbiter Challenger (OV-99)
• Rogers Commission Report
• Astronautix on Challenger
• Space Shuttle Challenger: A Tribute – slideshow by Life magazine
• Challenger Mission Videos of the Accident from Spaceflightnow.com
• NASA film on the accident and investigation downloadable from archive.org The Internet Archive
• Memorial to Greg Jarvis in Hermosa Beach, California at "Sites of Memory"
• Personal Observations on the Reliability of the Shuttle by R. P. Feynman
• RealPlayer video of Feynman's O-Ring demonstration (low quality)
• CBS Radio news Bulletin Anchored by Christopher Glenn of the Challenger Disaster from January 28, 1986, Part 2 of CBS Radio coverage of Challenger Disaster, Part 3 of CBS Radio News coverage of Challenger disaster, Part 4 of CBS Radio news coverage of challenger disaster
• Image of silo storing Challenger debris
• Space Shuttle Memorial covering both space shuttle disasters

v t e STS-51-L Main articles Space Shuttle Challenger STS-51-L Space Shuttle Challenger disaster STS-51-L Mission timeline Space Shuttle Challenger launch decision Crew Scobee (Cmdr) Smith Resnik Onizuka McNair Jarvis McAuliffe See also Rogers Commission Report Space Shuttle Solid Rocket Booster TDRS-B

v t e Space Shuttles United States Space Shuttle program (list) Soviet Buran programme Pathfinder (OV-098, ground tests) Enterprise (OV-101, atmospheric tests, retired) Columbia (OV-102, destroyed 2003) Challenger (OV-099, destroyed 1986) Discovery (OV-103, retired 2011) Atlantis (OV-104, retired 2011) Endeavour (OV-105, retired 2011) OK-GLI (Buran Analog BST-02, aerotester) Buran (Shuttle 1.01, destroyed 2002) Ptichka (Shuttle 1.02, 95–97% completed) Baikal (Shuttle 2.01, incomplete) 2.02 (partially dismantled) 2.03 (dismantled)