HL-20 was a lifting body spaceplane concept researched and studied by Langley Research Center (LaRC) for manned orbital missions using an expendable launch vehicle. It had a similar design to the Soviet Bor-4.
HL-20 was designed for low operations cost, improved flight safety and to land on conventional runways. It was also to complement the Space Shuttle system and provide assured manned access to space for the next generation of space programs in the 1990s.
Length: 9m (29 feet)
Span across the wingtips: 7.2 m (23.5 feet)
Number of Crew: Two flight crew and eight passengers
Empty Weight: 10,000kg (22,000 pounds)
HL stands for horizontal lander.
Personnel Launch System (PLS)
The aim of the PLS mission was to create a small space taxi system to transport people and small amounts of cargo to and from low-Earth orbit. It was not approved for full development.
Langley had conceived the HL-20 lifting body as a candidate for the Personnel Launch System (PLS). This system was designed for the primary mission of changing the Space Station Freedom crews.
In 1983, the Vehicle Analysis Branch (VAB) began the investigation of a small spaceplane (Bor-4) being orbited several times by the Soviets starting in 1982 and recovered in the Indian Ocean and Black Sea. During recovery operations of the space plane in the Indian Ocean, a P-3 Orion aircraft obtained photographs of the vehicle both floating in the water and being hauled aboard the recovery ship. This provided valuable insights into the shape, weight and center of gravity of the vehicle. Based on this information, small wind tunnels models were produced and tested in the NASA Langley wind tunnels. The results demonstrated the vehicle had good aerodynamic characteristics throughout the speed range from orbital entry interface to low supersonic speeds. LaRC continued to investigate the aerodynamic characteristics of this shape and examined some shape changes to improve the low speed aerodynamics from transonic down to subsonic speeds. LaRC personnel who had worked in the 1960’s on lifting bodies, especially the HL-10, were available to conduct these aerodynamic and shape modification tests.
Crew Emergency Rescue Vehicle:
As a result of the 1986 Space Shuttle Challenger accident, interest rapidly developed in developing a crew emergency rescue vehicle (CERV) for the proposed U.S.A / International space station for use if the Shuttle was unavailable for use (assured access) or station astronauts had to return to Earth in an emergency. In late 1986, VAB began to study the use of the lifting body shape as a CERV. This involved internal layouts, weight estimations, and center-of-gravity estimates for a vehicle of large enough scale to accommodate up to 8 space station crew members.
In October 1989, Rockwell International (Space Systems Division) began a year-long contracted effort managed by Langley Research Center to perform an in-depth study of Personnel Launch System (PLS) design and operations with the HL-20 concept as a baseline for the study.
In October 1991, the Lockheed Advanced Development Company began a study to determine the feasibility of developing a prototype and operational system. The study objectives were to assess technical attributes, to determine flight qualification requirements and to develop cost and schedule estimates.
In 1991, a full-size engineering research model of the HL-20 was constructed by the students and faculty of North Carolina State University and North Carolina A & T University for studying crew seating arrangements, habitability, equipment layout and crew ingress and egress.
The program was cancelled in 1993.
Did you know?
The Freedom Space Station concept eventually became the International Space Station (ISS). Construction of the ISS began in 1998 and the first crew arrived in 2000.
Dream Chaser is derived from NASA’s 1990 HL-20. It will be used to carry cargo to the ISS.
HL-42 was a proposed scaled-up version of the HL-20.
- HL-20 Model for Personnel Launch System Research:
- NASA Dryden HL-20 Graphics Collection:
- Hl-20: By Mark Wade
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