Week of August 19, 1996
Once the spacecraft arrived and unpacked at KSC, one of the first things we did was re-run several "EDL runs" in several different conditions on the spacecraft (EDL stands for Entry Descent and Landing). We wanted to re-verify some minor changes in the flight software that automatically controls the detailed series of events in this critical mission phase. In these tests, the software starts out in the late cruise mode of operation. Using support equipment that can "stimulate" accelerometers to simulate the effects of the deceleration of entry and landing, as well as other equipment that can simulate the data that comes from the radar altimeter, the entire EDL process can be artificially created without having anything really happen (other than petal and airbag retraction actuators moving). These tests were quite productive. In several cases we even "pulled the plug" on the computer and let it re-boot, with great success. This was the next-to-last time that the EDL software will be run on the real lander, the next time will be on the Fourth of July, 1997!