By Leslie Ringo
August 10, 1998
The VMS is only one tool used to train the Astronauts for the landing portion of a space mission. Another training vehicle used by the Astronauts is called the Shuttle Training Aircraft or STA. The STA started out as a Gulfstream business jet, but many engineering modifications and a sophisticated flight computer allow this jet to fly as a Shuttle would for the landing approach to a runway. I was given the opportunity to be an observer on an STA orientation flight. This flight opened my eyes to the different ways astronauts are trained compared to the VMS.
There are four Shuttle Training Aircraft available at any one time. Sometimes they are used prior to shuttle launches or landings to check weather conditions. For training purposes, my flight started out at El Paso, Texas and all runway approaches were made to White Sands, New Mexico. Inside the cockpit, the left seat was modified to have only Shuttle instrumentation and controls for the astronaut. The right seat was for the instructor pilot who flew with instruments and controls you would find on a typical business jet. The flight simulation engineer sat in the center jump seat. The flight simulation engineer was responsible for setting up the next run. For all of the approaches, I stood behind the flight simulation engineer to see what the astronaut might see on a landing approach.
So what was a typical approach like on the STA? A typical approach to a runway usually starts at around 16,000 feet. The plane would then deploy the main landing gear and engine reverse thrusters. This would create large amounts of drag that put the STA into an 18-20 degree dive to the runway. In comparison, a standard commercial airline approach to a runway is between 2-3 degrees. When the aircraft is at 2,000 feet, the astronaut starts a fast pull up that generates forces 1.5 Ð 2.0 times gravity, or what you would feel if you were in a swing. A "simulated touchdown" actually occurs once the STA main gear has reached about 20 feet above the runway. This is considered a touchdown since the pilot is at the same location he would be if he were in the actual Shuttle (see figure). After the "touchdown", the instructor pilot exits the simulation training run and climbs to set up for another run. Each astronaut completes 10 approaches for their training flight with the STA.
Several engineering observations were made during these STA approaches. It clearly pointed out differences between the STA and VMS. Since the STA does not actually land on the runway during a training approach, it was obvious the VMS plays an important role for the rollout phase. For a VMS simulation, we can easily blow tires, modify the height of the nose landing gear, or fail the chute. With these failures, we can successfully guarantee no damage an aircraft. That's the best thing about a computer simulation, you can quickly reset to any Shuttle configuration you desire.
Without a doubt, the STA orientation flight was both exciting and very informative!