Move aside Concorde

The shuttle just landed, and even though I had nothing to do with this (or for that matter any) mission (I work for the Space Station Program), I am so happy right now! I have every intention of becoming a doctor and leaving the space program...but I will miss days like today.

In this picture, Atlantis is about a minute away from landing flying an approach slope of negative 22 degrees (seven times steeper than a commercial aircraft's approach)! The vehicle is impressive in so many ways, but there is one story which ranks as one of my favorites.

The shuttle experiences eight minutes of powered flight during its ascent. During these eight minutes, a variety of abort options exist should an engine go out, a cabin leak develop, etc... During roughly the first half of the ascent, the vehicle would have to flip and come back to the Kennedy Space Center - a maneuver we would rather not do in a vehicle which has been described as a "flying brick." During the next 1.5-2 minutes, the vehicle still lacks the energy to make it into orbit on fewer than three engines, but could make it to a landing site in Europe or on the eastern seaboard (depending on the launch inclination). After about the T+5:30 mark, the vehicle has enough energy to make it into a lower-than-desired but safe orbit in a maneuver called an Abort To Orbit (ATO).

In the history of the shuttle program, only one in-flight abort has ever been called. It was on Challenger's STS 51-F which launched in the summer of 1985. At T+5:45, a main engine shut down and the crew initiated an ATO - burning the remaining engines longer to achieve a stable orbit. Had the engine shut down 30 seconds earlier, the crew would have turned the vehicle upright and flown to a European landing site. Years later, the pilot of that mission (Gen. Roy Bridges) was speaking to a group of us at Purdue (his alma-mater) when he mentioned that there was always a small part of him that wished that engine had gone out earlier. "We would have reset the trans-Atlantic crossing record" he explained. The current record is 2 hours 53 minutes by the Concorde[1] - Challenger would have reset it to 22 minutes!