The legacy of BOR-4

For most of the 1980s the BOR-4 vehicles were widely interpreted in the West as subscale models of a military spaceplane to be launched by the Zenit rocket, a program that was believed to run parallel to the Energiya-Buran effort (see Chapter 7). But, even as BOR-4 led a life of its own in the imagination of Western analysts, the Russians were considering using the spacecraft for other missions. One vehicle, possibly the one that had originally been supposed to fly the fifth BOR-4 orbital flight, was modified for an experiment to evaluate radio transmissions during atmospheric re-entry from a suborbital mission. Dubbed BOR-6, it was equipped with two large antennas extending out and downward from the nose. Using a special cooling system, these antennas were designed to see if radio signals could penetrate the plasma sheath that envelops spacecraft during re-entry and causes radio black­outs. Construction of the spacecraft was finished by 1990, but it was never launched due to the collapse of the Soviet Union and the ensuing shutdown of the Buran program. The Russians also looked at the possibility of converting BOR-4 type vehicles into space-to-ground weapons as part of a Soviet “Star Wars” program (see Chapter 8).

With the political climate changing and the Russians scrambling to find new customers for their space technology, BOR-4 was offered on a commercial basis to the international community in the early 1990s. The European Space Agency weighed the possibility of using BOR-4 vehicles to test the heat shield of Europe’s Hermes spaceplane, but these plans never materialized.

Interestingly enough, as early as 1983 the BOR-4 recovery images inspired engineers at NASA’s Langley Research Center to clandestinely build small models of the subscale spacecraft. Over subsequent years they analysed and improved the design in over 1,200 wind tunnel and computer tests to refine the shape of the outer mold line. This resulted in plans for a 10-ton spaceplane called HL-20, a lifting body closely resembling BOR-4 and considered in the early 1990s as a crew transportation system and crew rescue vehicle for the Freedom space station. Also known as the Personnel Launch System (PLS), it would be launched by an expendable rocket such as the Titan-4 and be capable of carrying a crew of 10. Although a full-scale mock-up of the HL-20 was built, the design was not selected for further development as the Russian Soyuz spacecraft was picked as the lifeboat for Freedom and eventually the International Space Station. Later in the 1990s Langley proposed a 42 percent dimensional scale-up of the HL-20 called the HL-42, but this seems to have been a short-lived effort.

The BOR-4/HL-20 design was once again picked up by the Orbital Sciences Corporation in the late 1990s for a “Space Taxi” proposed initially under NASA’s Space Launch Initiative and later as a candidate for the Orbital Space Plane that would complement the Shuttle by carrying crews to and from orbit, but the project was canceled after the February 2003 Columbia accident.

In January 2006 NASA announced a program called Commercial Orbital Trans­portation Services (COTS) in which two industry partners would receive a combined total of approximately $500 million to help fund the development of a reliable, cost- effective commercial transportation system to support the International Space Station after the retirement of the Space Shuttle in 2010. One of the vehicles studied was SpaceDev’s Dream Chaser. Having the same size and outer mold line as BOR-4 and the HL-20, it would fly six rather than ten passengers in order to save weight. Although Dream Chaser was eventually not selected, SpaceDev founder Jim Benson created a new company called the Benson Space Company that intends to purchase multiple Dream Chaser vehicles from SpaceDev to become the first-to-market with a spaceship designed for both suborbital and eventually orbital flights. Benson hopes it will also be used to transport people and cargo to the International Space Station and to a variety of emerging private-sector orbital destinations [18].