Spacecraft Processing 101

All Expendable Launch Vehicle (ELV) spacecraft undergo a specialized schedule of prelaunch processing, from the arrival of the spacecraft and any associated equipment until it is finally integrated with the launch vehicle.

Spacecraft typically arrive at Kennedy Space Center (KSC) or Vandenberg Air Force Base four to six weeks before launch, either from the manufacturing plant or an associated NASA center. Occasionally, other hardware or instrumentation that will be part of the spacecraft are shipped separately.

Upon arrival, the spacecraft and ground support equipment are transported to a nearby processing hangar, where they will undergo a series of pre-launch tests and flight simulations. Prelaunch testing of spacecraft often includes testing of special instrumentation as well as System Performance Tests, or functional tests, which verify that all spacecraft systems are functioning to their full design capabilities.

For Delta and Atlas launches: Once the spacecraft is prepared for flight, it is mated to the launch vehicle's payload attach fitting and a third stage solid-propelled booster. After it is transported to the launch pad and hoisted atop the launch vehicle, electrical and mechanical connections are verified with an interface verification test. The final major test before launch, the Flight Program Verification, is a simulated flight test of the launch vehicle and spacecraft together. After this test, the payload fairing is enclosed around the spacecraft, and the integrated payload is ready for launch.

For Pegasus launches: Once the spacecraft is checked out and ready for flight, it is mated to the Pegasus launch vehicle. Prior to encapsulation into the fairing, a final flight simulation is conducted. The fairing is then installed and the integrated Pegasus vehicle and spacecraft are transported to the “Hot Pad” located adjacent to the runway. There mating to the underside of the L-1011 Orbital Carrier Aircraft occurs. All mechanical and electrical interfaces are then verified with a Combined Systems Test. Finally, on launch day, the flight line closeouts of the vehicle are performed.

NASA conducts two meetings, a Flight Readiness Review and Launch Readiness Review, a few days before launch to obtain concurrence to load the spacecraft with propellant and to enter the countdown on the intended date.