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There’s new interest in a reusable vehicle that could be anywhere on in less than an hour.

The

By Suzann Chapman, Associate Editor

asa and US industry are devel- Requirements, in a January interview. data about the history, critical tech- N oping reusable The team is not locked into one mis- nologies, and possible missions in a technologies with an eye toward cutting sion area—such as space operations, briefing called “Military Space­planes: costs and reestablishing US dominance which covers launch. Instead The Future.” in the field. The Air Force, however, they applications across all One key question for the team con- has begun to envision RLV applications space missions. Hence the use of the cerns whether a spaceplane could help that go beyond pure . broad­er term “spaceplane.” US space forces conduct their tasks In May 1996, officials at Air Force The USAF team, which includes more efficiently and cheap­er than they and Air Force Ma- NASA and Air Combat Command do today. The civil-commercial RLV teriel Command created a military personnel, developed a concept of effort is geared toward providing low- spaceplane integrated concept team operations last summer. It envisions er-cost, reliable, and fast-turnaround to capitalize on the NASA-led effort -like operations with rapid turn­ space transportation. That satisfies to produce an RLV demonstrator, around time; operations to, through, and only one aspect of the US military the X-33. “The [AFSPC and AFMC] from space; multimission capability; space missions: launch. commanders asked us to look at what and worldwide operations from conti- The ability to perform space con- mission areas might be satisfied by this nental US basing. trol—that is, ensuring safe passage of technology, at the timing, and then to Over the past several months, AF- US on and denying an establish a roadmap,” said Brig. Gen. SPC officials pulled together basic enemy the ability to use its satellites Herbert M. Ward, AFSPC director of against the US or its allies—does not 62 AIR FORCE Magazine / March 1997 exist today. Nor does the US possess around for more than 50 years. In 1944, of RLV technology that they have any capability to apply force from two German scientists, Eugen Sanger already begun to discuss follow-ons space, other than with an ICBM, and Irene Bredt, set down their prewar to the X-33. whose trajectory would take it through and postwar work into a concept for space before it plunged back to strike a hypersonic -powered aircraft Today’s RLVs a target on Earth. that could be boosted into orbit, then NASA began a three-pronged RLV For that reason, the Air Force’s glide back to Earth—creating the term program in 1994. The research effort team members are also looking at “boost .” NASA officials credit includes technology demonstrations the potential of military the Sanger-Bredt work with directly with the DC-XA, X-34, and X-33— to provide space control and force influencing the shape of the first US each designed to demonstrate various application from space, as well as to spaceplane, the X-15, conceived in technologies that could lead to a com- provide force enhancement, such as 1954. From it, USAF’s Dyna-Soar X- mercial RLV. space surveillance, reconnaissance, 20A, and the follow-on lifting bodies, NASA and McDonnell Douglas warning, and communications. the US developed technologies that led upgraded the DC-X, a subsonic rocket A military spaceplane might take to the . flown eight times by Phillips Lab from military payloads into orbit, deorbit However, today, the Air Force, 1993 to 1995. The DC-XA, Clipper payloads, or perform on-orbit main- NASA, and industry maintain that the Graham, made four successful tenance. It might release a satellite in technology for turning the original demonstrating its vertical ca- space, then come back into suborbit concept into reality now exists or is pability. However, testing ended July and fly around the globe once or twice very close at hand. 31, 1996, when the vehicle toppled to conduct communications support Both the Air Force and the Navy and exploded after its fourth . or bomb-damage assessment. It could collaborated with NASA on the X-15 The rocket tipped over, according take advantage of the high ground of program, which produced three ve- to an incident investigation released space and, with operations closely hicles for hypersonic aerodynamic January 7, because “a brake line on the resembling a conventional ’s, research. In all, 199 flights took place pneumatic system for landing fly over any region of the globe with from 1959 through 1968 in which the gear number two was not connected.” impunity. X-15s reached Mach 6.7 and an altitude NASA officials believe the four DC- General Ward emphasized that he is of 354,200 feet. XA test flights will aid RLV research not predisposed to a particular RLV The lifting bodies, such as the light- but do not plan to build a follow-on concept. He said that no decisions weight M2-F1 and heavyweight M2-F2, DC-XB. had been made concerning whether HL-10, and X-24A and B, were wingless The second element of the RLV the spaceplane should be manned or vehicles designed to fly back to Earth program features the X-34, a single- unmanned, employ vertical or hori- from space and land like . rocket with short and a zontal , or be single-stage or Versions of these lifting bodies, both small tail surface capable of flying at multistage to orbit. powered and unpowered, flew success- Mach 8 and an altitude of 250,000 feet. Early successes in NASA’s current fully from 1963 to 1975. Orbital Sciences Corp. is developing RLV effort, which since its inception Probably the most recent US re- the X-34, which will be carried aloft has included participation by engi- search effort was the high-profile aboard OSC’s L-1011 aircraft. It is neers from USAF’s Phillips Lab at USAF-NASA National Aerospace scheduled to fly in 1998. Kirtland AFB, N. M., spurred officials Plane (NASP), or X-30. Established at The final element is the larger, more to formalize the operational concept Wright-Patterson AFB, Ohio, in 1986, powerful X-33 test vehicle, which will team to ensure that they would be in the NASP program heralded some of reach Mach 15 and altitudes of up to a position to use those technologies the same concepts now set forth by the 50 miles. It will be half the size of when they matured. When that might spaceplane concept team. However, but demonstrate all the technologies be is another question that concerns budget cuts forced the program’s needed for a full-scale RLV. NASA the team members. demise in 1994. selected Lockheed Mar­tin to build the The concept team will try to answer AFSPC officials point out that timing X-33, based on its lifting-body concept these questions when it reports this and technology separate NASP from the called Venture­Star. It has a new aero- spring. It will also try to determine current spaceplane concept. The technol- spike engine and will launch vertically what kind of investments to make in ogy is more mature now than it was 10 but land like an airplane. The first test research and development or proto- years ago. They said the key also is to flight for the X-33 single-stage-to-orbit typing to develop that capability for ensure that the system is affordable, as vehicle is set for March 1999. the Defense Department. “One of our well as useful. NASA officials stated last year that responsibilities is to go back to our The US is not the only country they are already working on technology commanders with the roadmap that interested in spaceplanes. Britain has beyond the X-33. They are looking at says if this technology is mature then developed several spaceplane con- air-boosted rocket , currently we can do the step and these are cepts, some of which date to the 1950s. under study, as well as the possibility for the kinds of funds required,” stated began research into spaceplane small two-stage vehicles. Unofficially General Ward. technology in 1987. The European dubbed “X-37,” the effort would prob- Space Agency had similar thoughts ably include two to four variants rather Not Really Déjà Vu in mind when it designed its than one, as with X-34 and X-33. The The spaceplane concept is not really manned spaceplane. only criteria, they said, is that they be new. In fact, the general idea has been NASA officials are so confident reusable. ■

AIR FORCE Magazine / March 1997 63