Private industry could be prepared to go where NASA fears to tread and develop a spaceplane to replace the space shuttle and ferry crews to and from the International Space Station. But if industry succeeds, it will be thanks to decades of work by the space agency on lifting-body reentry vehicles.

While its plans for replacing the shuttle are in flux, NASA has a small program underway intended to stimulate private-sector efforts to develop commercial human spaceflight services. While most of those involved are pursuing Apollo-style capsules similar to NASA’s Orion crew vehicle, one is designing a spaceplane.

The Dream Chaser, developed by Sierra Nevada Corp. subsidiary SpaceDev, is based on NASA’s HL-20 lifting-body design, which reached the stage of a full-scale research model before work was discontinued in the early 1990s. With NASA now considering bids for a second round of the Commercial Crew Development (CCDev) program, another spaceplane contender has emerged.

The “blended lifting-body” vehicle proposed by Orbital Sciences Corp. for CCDev 2 is based on the larger Orbital Space Plane (OSP) the company designed in the early 2000s under NASA’s Space Launch Initiative, a previous but abortive effort to develop a next-generation reusable launch system to replace the shuttle.

Both proposals draw heavily on NASA work on lifting-body space vehicles that ran from the late 1950s to mid-1970, then reemerged in the 1990s only to be shelved again. Beginning in 1963, with the plywood M2-F1 glider, and continuing through 1973, with the U.S. Air Force-sponsored X-24, atmospheric flight tests proved a lifting body could be maneuvered and landed safely and accurately.

Although NASA elected to pursue a winged design for the space shuttle, these tests showed the orbiter could be landed on a runway unpowered. The lifting-body concept resurfaced in 1989, when NASA Langley Research Center began studying a personnel launch system combining an expendable booster with a reusable spaceplane. The HL-20 concept progressed as far as a full-scale model before work ended in 1991.

Later in the 1990s, NASA dusted off the X-24A lifting-body configuration for its Crew Return Vehicle concept, intended as a lifeboat for the International Space Station. Drop tests of an 80%-scale prototype, the X-38, began in 1998, but the program was canceled in 2002 before a full-scale orbital test vehicle could be completed.

By then, a modified lifting-body configuration had been selected for the planned Orbital Space Plane, but the Space Launch Initiative ended in 2004—and the OSP with it—when NASA launched the Constellation exploration program with its Ares expendable launchers and Orion crew capsule.

With Constellation slipping, the shuttle’s retirement looming and contracts already in place for commercial cargo delivery to the ISS, NASA began the CCDev program in 2009 with $50 million in stimulus funding. The biggest part of that, $20 million, went to Sierra Nevada to mature SpaceDev’s Dream Chaser spaceplane design.

With $200 million in funding, CCDev 2 has drawn bids from Space Exploration Technologies (Dragon capsule) and Orbital Sciences Corp., as well as first-round performers Boeing (CST-100 capsule) and Sierra Nevada. Contracts are to be awarded in March. Both the Orbital and SpaceDev spaceplanes are designed for launch atop an Atlas V expendable booster.

The advantages claimed for a lifting body over a capsule include low reentry deceleration loads, large cross range and a low-impact runway landing. Ironically, as NASA selected a capsule for Constellation in part to save time, both Orbital and Sierra Nevada say they could fly in 2014, only a year behind the first planned (but unfunded) flight of Lockheed Martin’s Orion crew vehicle.