Challenger or OV-099 (Orbital Vehicle-099) was a American Space shuttle originally designed at ends of test (STA-099).
It bears the name of the boat which measured the sea-bed major of the sphere (the Fosse of Mariannes, with 10 983 m under water surface).
Challenger exploded the January 28th 1986, during takeoff, after only 73 seconds of flight whereas it evolved/moved with 3 200 km/h. The seven members of the crew perished. It is about:
- Francis R. Scobee, commander,
- Michael J. Smith, pilot,
- Judith A. Resnik, Ellison S. Onizuka, Ronald E. McNair, specialists in mission,
- Gregory B. Jarvis, Sharon Christa McAuliffe, specialists in payload.
Missions
STS means Space Transportation System or space transport system. It is the official term to indicate the shuttles.
On the whole, Challenger achieved 9 missions during which it spent 62,41 days in space and traversed 41 527 416 km. It deployed 10 satellite S on the whole.
The accident
See also: Explosion of the space shuttle Challenger
The accident was caused by the rupture of the one of the joints of one of the two powder boosters joined with the principal hydrogen tank. He had suffered from particularly cold climatic conditions during the night preceding the shooting. The joints in question, developed by an American company Morton Thiokol located at the north of the the United States, had not been tested in conditions of great cold. The originators considered that the place of shooting, the Florida, profited from an always sunny climate. The fact is that a weather phenomenon concerning rather frequently Florida had reduced the temperature well in lower part from the freezing point during the night preceding the shooting.
Engineers de Morton Thiokol had nevertheless serious doubts about the capacity of resistance of the cold joint, because in particular of incidents noticed during certain preceding flights. But the joint not having been formally tested since the question of the cold had not even arisen, they were unable to prove the weakness of this part to the director of shooting.
A simple intuition did not have its place in the rationality of the very complex procedures of decision making of NASA. The investigation will also reveal that the engineers of safety of NASA estimated the probabilities of accident of the whole of the device at approximately 1% whereas the directors of shootings, making the final decision, counted of the probabilities thousand times lower. In these two contexts, information concerning the solidity of the joint did not become same extensive. The directors of shootings thus decided to pass in addition to and to carry out the shooting. Disastrous decision which cost the life seven astronauts.
The progressive rupture of the joint on the solid strap-on booster (SRB) of right-hand side let pass a flame directed towards structural elements of the principal fuel tank. Towards T+72,284 seconds the structure of the principal tank and engines of supplements starts to release and disintegrates towards T+73,124 S. the orbitor, still intact, swivels of its optimal orientation to resist the intense aerodynamic loads (close to the max Q, or moment of aerodynamic pressure maximum) and tears immediately of pieces (T+73,213 S).
Challenger was not destroyed by a Explosion. After disintegration due to the aerodynamic loads, the fuel which was in the orbitor and the principal tank burns in a few seconds, creating a massive fireball.
The cockpit, always largely intact, fell down towards the ocean.
It was proven that at least some astronauts survived the initial shock (a bail-out bottle was found struck), and that they died at the time of the impact of the cabin before (of which the structure had resisted) on the sea. The fall was one 36 seconds duration.
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