The Air Force has pursued this concept for the past 40 years. Is the Spaceplane Dead? SPACEPLANE has been part Ideas for a spaceplane date back By Rebecca Grant of the Air Force’s long- to German research on rocketry be- A range vision for more than fore World War II. In the Air Force, 40 years. Advocates say a reusable a reusable spaceplane has long been spaceplane could cut launch costs part of the vision for full control and from $10,000 per pound of cargo to exploitation of air and space. $1,000 per pound and give the Air Force much greater flexibility in Schriever’s Vision access to space, whether for main- In 1962, Gen. Bernard A. Schriever taining satellites or performing other described a set of requirements for missions. space capabilities that included the It would also provide the ultimate ability to orbit, maneuver, rendez- counter to any adversary’s anti-ac- vous, de-orbit, re-enter, and land on cess strategies; a spaceplane that can a routine basis. Today, USAF is still fly at Mach 25, reach orbit, and re- at least a decade away from acquir- turn to Earth would be virtually im- ing a reusable spaceplane that can possible to stop before reaching its do the jobs Schriever described. objective. Technology hurdles remain at the But today, there is no single heart of the issue. Hypersonic flight— “spaceplane” on the drawing boards. defined as flying faster than Mach Several experimental vehicles are 5—began to tantalize aerospace en- seeking to demonstrate the technolo- gineers in the 1950s. One early suc- gies needed for a spaceplane. A De- cess was the North American X-15, cember 2000 report from the Air tested at speeds up to Mach 6.7 in the Force’s Scientific Advisory Board 1960s. But for the most part, pro- laid it out: “If the Air Force vision of grams dealing in hypersonics and ‘controlling and exploiting the full reusable spaceflight made only lim- aerospace continuum’ is to become ited progress. One such was the reality, the Air Force needs a com- Boeing X-20 Dyna-Soar, a boost- prehensive plan for hypersonics.” glide vehicle designed to become a Yet the Air Force has been sty- manned, orbital plane. The Air Force mied in its efforts to get Washington funded it in 1957, but Secretary of behind a stated requirement for a Defense Robert S. McNamara can- spaceplane or to fund the extensive celed the X-20 in 1963, and Phase 1 research that is still needed to make of the hypersonic spaceplane era was the concept a reality. The recent de- over. mise of the X-33 spaceplane project Dyna-Soar and other programs signaled that once again, the tech- contributed to the manned space nology hurdle is high and the gap shuttle program. NASA’s space between dollars and rhetoric is deep. shuttle first flew in April 1981 and 68 AIR FORCE Magazine / November 2001 truck and a strike platform, the space- plane would be a revolutionary leap. No “Golden Mission” However, research on NASP stalled when it failed to meet performance goals. By the early 1990s, NASP was projected to be a decade late and 500 percent over budget. NASP was “fully capable of hypersonic flight,” according to the Science Advisory Board, but could not reach orbital velocity. Advanced hypersonic tech- nology remained out of reach. “On the basis of current knowledge, it is hard to defend previous DOD plans for NASP,” concluded a RAND report in 1989. “No compelling ‘golden mission’ exists for NASP.” Cuts in the defense budget and the The quest for hypersonics and reusable spaceflight led in 1957 to the Dyna- end of the Cold War sealed the fate Soar X-20. It was designed to be a manned orbital craft and did contribute to of NASP and the program was can- the space shuttle program but was canceled in 1963. (Artist’s concept) celed in 1994. “These are exciting ideas,” said Martin Faga, assistant has logged more than 100 successful As a result, the National Aero- secretary of the Air Force for space missions, sometimes flying on a space Plane was to be a revolution- at the time, “but they are not ready monthly basis. Still, the shuttle’s need ary advance: a transatmospheric craft for commitment.” for expendable tanks to help it reach that would provide cheaper space Even before the death of NASP, orbit and the continued high cost of launch and the ability to exploit space researchers were focusing on a more each launch differed from the con- in military operations. Plans called cautious approach that divided up cept of a true spaceplane. Better ac- for NASP to fly as a single stage to the technology hurdles of hypersonic cess to space continued to be a driv- low Earth orbit and to cruise at hy- flight and reusable systems. ing issue. personic speeds of Mach 12 to The next “spaceplane experimen- In 1986, President Reagan rein- Mach 25 in the transatmosphere— tal” was an early success that raised vigorated the idea of an airplane- between the altitudes of 100,000 to hopes for both military and commer- like transatmospheric spaceplane. In 350,000 feet. cial applications for a spaceplane. 1986, he called for “a new Orient With the advent of NASP, the McDonnell Douglas won a contract in Express” that could, by the end of spaceplane concept branched into two 1991 to build what became the DC-X the 1990s, “take off from Dulles roles. Delta Clipper. This single-stage-to- Airport and accelerate up to 25 times First, a reusable spaceplane might orbit vehicle grew out of an SDI re- the speed of sound.” In Reagan’s replace the space shuttle as a launch quirement for a single-stage, reusable concept the transatmospheric plane platform carrying heavy payloads for vehicle that could put Brilliant Pebbles, could attain low Earth orbit or stay customers like the Strategic Defense a component of a ballistic missile de- in the atmosphere, “flying to Tokyo Initiative Organization, which con- fense system, into orbit at a reason- within two hours.” tributed heavily to NASP research able price. It was managed by the Air Behind Reagan’s sensational an- funding. Air Force Brig. Gen. Ken- Force for SDIO, later the Ballistic nouncement was hope for a techno- neth E. Staten, NASP program man- Missile Defense Organization. logical breakthrough in the field of ager, said in 1986 that NASP might Although the program was handed hypersonics. Research from a De- be able to deliver payloads to orbit off to NASA, the Delta Clipper stirred fense Advanced Research Projects for “between one percent and 25 Air Force thinking on the possible Agency–funded secret program called percent of the expense of doing it uses of a spaceplane. The commer- Copper Canyon suggested that ac- with the shuttle.” cial potential and simplicity of the tive thermal management could boost Second, for the Air Force, NASP program seemed to foreshadow a new the power of a scramjet engine. In- could also be a lightning-fast bomber. era when commercial launch demand stead of succumbing to a heat barrier Gen. Lawrence A. Skantze in 1985, would help fund spaceplane tech- around Mach 8, the friction from the as commander of Air Force Systems nologies. atmospheric drag would be used as Command, said NASP might have The Delta Clipper was not a hy- part of a system to superheat hydro- “the speed of response of an ICBM personic scramjet spaceplane but a gen fuel then inject it into a scramjet and the flexibility and reliability of single-stage rocket with advanced engine. Using this technique, a space- a bomber, packaged together in a lightweight materials and directional plane might overcome the thermal plane that can scramble, get into or- control. Its charter was to demon- drag barrier by dissipating heat, while bit, and change orbit so [that] the strate the ability to take off and land using the energy to boost engine per- Soviets can’t get a reading accurate vertically, using controlled, rocket- formance. enough to shoot at it.” As a satellite powered flight. In its full concept, AIR FORCE Magazine / November 2001 69 the Clipper would be a reusable ve- All programs shared the same phi- space shuttle program. The linear hicle that could be launched and re- losophy: rapid development of proto- aerospike was designed to increase covered at the same site by a small types, with no more than a few years power and, more importantly, per- ground control team. Maintenance passing between contract award and form with maximum efficiency at a would be streamlined, leading to demonstration. Some, like Boeing’s greater range of altitudes. lower operating and support costs X-37 and X-40, were demonstrators Test of the linear aerospike en- that would bring about a dramatic for a vehicle that would be ferried into gines proceeded smoothly through a reduction in the price of launching orbit, operated by its own rocket en- series of test runs in 2000. The payloads into orbit. The subscale gine, then would return to land on a aerospike engine project manager, demonstrator and an advanced ver- runway. In contrast, Lockheed Martin’s Donald Chenevert, praised the per- sion, the DC-XA, successfully com- X-33 was designed to take off verti- formance of the engines, noting that pleted a series of flights in the pe- cally, fly a suborbital path, and then “few new, much less innovative, riod 1993–96, demonstrating control land horizontally at a US base. Orbital engines even get to full power in so and maneuverability at the White Sciences’ X-34 was a rocketplane de- few tests,” but with X-33’s engines, Sands Missile Range in New Mexico.