Hitchhiker Program  The Hitchhiker Program (HH) was a NASA program established in 1984 and administered by the Goddard Space Flight Center (GSFC) and the Marshall Space Flight Center (MSFC). The program was designed to allow low-cost and quick reactive experiments to be placed on board the Space Shuttle. The program was discontinued after the Space Shuttle "Columbia" disaster of STS-107. NASA's Hitchhiker project began in early 1984. It was created to accommodate small attached payloads in the Space Shuttle payload bay. Hitchhikers were intended for customers whose space activity requires power, data or command services. The first Hitchhiker launched on STS-61-C on January 12, 1986. Called HHG-1, it was mounted to the side of the payload bay and carried three experiments. The second Hitchhiker launched on STS-39 on April 28, 1991. This payload was called Space Test Payload (STP)-1 and consisted of five experiments mounted onto a cross-bay carrier. Between 1992 and 1995, 12 Hitchhikers were manifested to fly on the Space Shuttle. The Hitchhiker system provided real-time communications between the payload and customers in the Hitchhiker control center at Goddard Space Flight Center, Greenbelt, Maryland. The system also provided crew control/display capability, if necessary. Hitchhikers were created to provide a quick reaction and low cost capability for flying small payloads in the Shuttle payload bay. Along with NASA's Get Away Specials (GAS), Hitchhiker was developed and operated by the Goddard Space Flight Center Shuttle Small Payloads Project (SSPP). Unlike Hitchhikers, GAS payloads were only mounted in canisters, did not connect to orbiter electrical services and did not require significant Shuttle support. Hitchhiker experiments were housed in canisters or attached to mounting plates. The Hitchhiker canister came in two varieties—the Hitchhiker Motorized Door Canister and the Sealed Canisters. The Hitchhiker Motorized Door Canister had mechanical interfaces nearly identical to a GAS canister and could accommodate a customer payload of up to 160 pounds (72.6 kilograms). This canister allowed a payload to be exposed directly to the environment of space. The Sealed Canister, without a door, could accommodate a customer payload up to 200 pounds (90.7 kilograms). The payload in this canister was sealed in an atmosphere of nitrogen or air. Experiments attached to mounting plates could be placed on the vertical plate, a 25 inches (63.5 centimeters) by 39 inches (99.1 centimeters) mounting surface for up to 200 pounds (90.7 kilograms) of customer hardware.