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Challenger (STA-099, OV-99)




Challenger, the second orbiter to become operational at Kennedy Space Center, was named after the British Naval research vessel HMS Challenger that sailed the Atlantic and Pacific oceans during the 1870's. The Apollo 17 lunar module also carried the name of Challenger. Like her historic predecessors, Space Shuttle Challenger and her crews made significant contributions to America's scientific growth.

Challenger joined NASA fleet of reusable winged spaceships in July 1982. It flew nine successful Space Shuttle missions. On January 28, 1986, the Challenger and its seven-member crew were lost 73 seconds after launch when a booster failure resulted in the breakup of the vehicle.

Challenger started out as a high-fidelity structural test article (STA-099). The airframe was completed by Rockwell and delivered to Lockheed Plant 42 for structural testing on 02/04/78. The orbiter structure had evolved under such weight-saving pressure that virtually all components of the air frame were required to handle significant structural stress. With such an optimized design, it was difficult to accurately predict mechanical and thermal loading with the computer software available at the time. The only safe approach was to submit the structural test article to intensive testing and analysis. STA-099 underwent 11 months of intensive vibration testing in a 43 ton steel rig built especially for the Space Shuttle Test Program. The rig consisted of 256 hydraulic jacks, distributed over 836 load application points. Under computer control, it was possible to simulate the expected stress levels of launch, ascent, on-orbit, reentry and landing. Three 1 million pound-force hydraulic cylinders were used to simulate the thrust from the Space Shuttle Main Engines. Heating and thermal simulations were also done.

Rockwell's original $2.6 billion contract had authorized the building of a pair of static-test articles (MPTA-098 and STS-099 and two initial flight-test vehicles (OV-101 and OV-102. A decision in 1978 not to modify Enterprise from her ALT configuration would have left Columbia as the only operational orbiter vehicle so on 1/29/79 NASA awarded Rockwell a supplemental contract to convert Challenger (STA-099) from a test vehicle into a space-rated Orbiter (OV-099).

STA-099 was returned to Rockwell on 11/7/79 and it's conversion into a fully rated Orbiter Vehicle was started. This conversion, while easier than it would have been to convert Enterprise, still involved a major disassembly of the vehicle. Challenger had been built with a simulated crew module and the forward fuselage halves had to be separated to gain access to the crew module. Additionally, the wings were modified and reinforced to incorporate the results of structural testing and two heads-up displays (HUD's) were installed in the cockpit. Empty Weight was 155,400 lbs at rollout and 175,111 lbs with main engines installed. This was about 2,889 pounds lighter than Columbia


Upgrades and Feature

Two orbiters, Challenger and Discovery, were modified at KSC to enable them to carry the Centaur upper stage in the payload bay. These modifications included extra plumbing to load and vent Centaur's cryogenic (L02/LH2) propellants (other IUS/PAM upper stages use solid propellants), and controls on the aft flight deck for loading and monitoring the Centaur stage. No Centaur flight was ever flown and after the loss of Challenger it was decided that the risk was too great to launch a shuttle with a fueled Centaur upper stage in the payload bay.


Construction Milestones


STA-099 Construction Milestones

July 26, 1972
Contract Award

November 21, 1975
 Start structural assembly of Crew Module

June 14, 1976
Start structural assembly of aft-fuselage

March 16, 1977 
Wings arrive at Palmdale from Grumman

September 39, 1977 
Start of Final Assembly

February 10, 1978 
Completed final assembly

February 14, 1978 
Rollout from Palmdale

OV-099 Construction Milestones

January 5, 1979
Contract Award

January 28, 1979
 Start structural assembly of Crew Module

June 14, 1976
Start structural assembly of aft-fuselage

March 16, 1977 
Wings arrive at Palmdale from Grumman

November 3, 1980 
Start of Final Assembly

October 23, 1981 
Completed final assembly

June 30, 1982 
Rollout from Palmdale

July 1, 1982 
Overland transport from Palmdale to Edwards

July 5, 1982 
Delivery to Kennedy Space Center

December 19, 1982 
Flight Readiness Firing

April 4, 1983 
First Flight (STS-6)


Challenger's Flights to Date


  STS-6 (04/04/83)

STS-7 (06/18/83)

  STS-8 (08/30/83)

41-B (02/03/84)

41-C (04/06/84)
41-G (10/05/84) 51-B (04/29/85) 51-F (07/29/85)

61-A (10/30/85)

51-L (1/28/86)

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