Challenger was destroyed in the second minute of STS-51-L, the orbiter's tenth mission, on January 28, 1986, when an O-ring seal on its right solid rocket booster failed due to record low temperatures. The O-ring became brittle and allowed a plume of flame to stream out of the SRB that weakened Challenger's external fuel tank, leading to the orbiter's rapid breakup under aerodynamic stresses. A subsequent investigation concluded that poor design of the SRB seals, unusually cold temperatures that weakened the O-rings, and lack of inspection were to blame for the disaster.