Space Shuttle Challenger - Loss of Challenger

Loss of Challenger

Challenger was destroyed as it broke up in mid-flight in the second minute of its tenth mission, on January 28, 1986, at 11:38:00 am Eastern Standard Time. 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. 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. All seven crew members were killed.