Discoverer 27, also known as Corona 9020A, was an American area survey optical reconnaissance satellite launched in 1961, but which failed to achieve orbit.
A Thor DM-21 Agena-B rocket was used, flying from Launch Complex 75-3-4 at the Vandenberg Air Force Base.
[2] The booster began exhibiting abnormal pitch gyrations within seconds of liftoff, which worsened during flight and eventually exceeded its design limits.
At T+59 seconds, the Agena disintegrated due to either structural loads or inadvertent activation of the range safety destruct charges.
The Thor's engine shut down due to loss of electrical power caused by damage to the forward section of the vehicle.