HL-20 Personnel Launch System - Proposed Missions

Proposed Missions

Originally, delivery of passengers to Space Station Freedom would have been the primary mission of a PLS. For the baseline space station mission, depending on design the crew size would be either eight or ten crew members.

A typical HL-20 mission operation would commence at the Kennedy Space Center with the HL-20 being processed horizontally in a vehicle processing facility while an expendable launch vehicle is processed vertically in a separate facility. The launch vehicle and HL-20 would be mated at the launch pad and the launch sequence initiated as the space station passes over the launch site.

Following launch, the HL-20 would initially enter a low 100-nautical-mile (200 km) orbit to chase after the space station and then transfer up to the space station orbit altitude of 220 nautical miles (410 km). After rendezvous and docking at Space Station Freedom, crews would be exchanged and the HL-20 would decelerate for return to Earth.

The HL-20 would land horizontally on a runway similar to the return of the Space Shuttle. Total mission duration could be as low as 72 hours.

Other potential missions defined for a PLS included the orbital rescue of stranded astronauts, priority delivery and observation missions, and missions to perform satellite servicing. For these other missions, the basic HL-20 design would be unchanged, but interior subsystems and arrangements would be modified according to crew accommodations, duration, and equipment required for the particular mission.