Space Shuttle Challenger - STS-51-F RSLS Abort, Launch, Abort-To-Orbit, and Landing
14On this day in 1985, Space Shuttle Challenger launched on STS-51-F, the only abort-to-orbit launch abort in program history.
Challenger's first launch attempt was on July 12, which is the opening sequence of this video, but proceedings were halted at T -3 seconds, after main engine start, due to a malfunction in coolant valves in main engine number 2. The main engines were shut down, and the launch campaign recycled to correct the problem. On July 29, Challenger successfully launched. At 5 minutes, 45 seconds into flight, Challenger's number 3 main engine was shut down automatically due to a failed temperature sensor in the engine's turbopump assembly, yielding erroneously high readings which were outside of operational limits. A further failure later occurred in the same instrumentation for engine 2, but a shutdown was inhibited by fast actions by mission control and Challenger's crew. Had Challenger lost a second engine, there was no viable abort mode remaining, and the crew likely would have been unable to survive an uncontrolled reentry. Even if the crew had managed to control Challenger in this emergency decent, any ditching attempt would have been entirely off-script, and likely non-survivable, as the Space Shuttle Orbiter was not rated for a water landing of any kind. Happily, the Abort-to-Orbit protocol functioned as designed, Challenger achieved a lower than planned, but safe orbit, and STS-51-F accomplished 85% of mission objectives. Challenger and crew returned safely to Edwards Air Force Base on August 6, 1985.
This video, as with my other restorations and reconstructions, has been upscaled using AI, and married to a custom composite audio track, comprised of high quality recordings of the Space Shuttle from the later years of the program.
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