The Careful Craft of Spacecraft Processing
All Expendable Launch Vehicle (ELV) spacecraft undergo a specialized schedule of prelaunch processing, from the arrival of the spacecraft and any associated equipment to its final integration with the launch vehicle.
Image to right: Workers watch as the Mars Exploration Rover Opportunity rolls over ramps to test its mobility and maneuverability. Credit: NASA
Spacecraft typically arrive at Kennedy Space Center in Florida or Vandenberg Air Force Base in California four to six weeks before launch, either from another NASA center or the manufacturer. Occasionally, other spacecraft hardware or instruments
are shipped separately.
Upon arrival, the spacecraft and ground support equipment are transported to a nearby processing hangar, where they undergo a series of prelaunch tests and flight simulations. Prelaunch testing of spacecraft often includes testing special instrumentation as well as System Performance Tests, or functional tests, which verify that all spacecraft systems are working 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 confirmed with an interface verification test.
Image to left: A worker in Hangar AE, Cape Canaveral Air Force Station, meticulously cleans the inside of a Boeing Delta fairing that will encapsulate the Swift spacecraft. Credit: NASA
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. The purpose: to make sure they're "go" to load the spacecraft with propellant and to enter the launch countdown as planned.
Image to right: Attached underneath the Orbital Sciences L-1011 aircraft is the Pegasus XL Expendable Launch Vehicle, which carried NASA's Solar Radiation and Climate Experiment into orbit. Credit: NASA
From interplanetary missions like the Mars Exploration Rovers and MESSENGER to missions like Voyager venturing past the edge of our Solar System, ELV missions have a dramatic impact on space exploration. These missions are made possible by the painstaking detail and dedication of the personnel who prepare each spacecraft and launch vehicle for the journey to come.