This is the third of a continuing series of historical fact sheets on the origins of NASA's X-33 program. The X-33 is a technology demonstrator for NASA's "next generation" of space launch vehicle. It will flight test a range of technologies needed for single-stage-to-orbit reusable launch vehicles, such as thermal protection systems, composite cryogenic fuel tanks, and the aerospike engine. Test flights are scheduled to begin in July 1999. Eventually, based on the X-33 experience shared with NASA, Lockheed Martin hopes to build a commercial single-stage-to-orbit reusable launch vehicle, called VentureStar. In the future, rather than operate space transport systems as it has with the Space Shuttle, NASA plans to purchase launch services from Lockheed Martin and other commercial launch providers.

The decision to design and build the X-33 grew out of a NASA study titled "Access to Space." Unlike other space transport studies, "Access to Space" resulted in the design and construction of a vehicle. The period preceding the "Access to Space" study is the subject of the first fact sheet, titled "The Policy Origins of the X-33." The second fact sheet deals with the specific chain of events that led to the creation of the "Access to Space" study, the conclusions of the so-called Option 3 team within the "Access to Space" study, and the role played by an experimental program run by the Strategic Defense Initiative Office (SDIO) of the Department of Defense. This third fact sheet reviews the conclusions of the Option 1 and Option 2 teams, relates the emergence of a tentative NASA program to build an experimental advanced technology demonstrator flight vehicle, the X-2000, and describes public and Congressional support for a single-stage-to-orbit spaceship. The X-2000 is of interest to the history of the X-33 project because of the close resemblance between the two programs and their experimental vehicles.

NASA's "Access to Space" study, as we saw in the preceding Fact Sheet, was commissioned by NASA Administrator Daniel Goldin on January 7, 1993, and headed by Arnold D. Aldrich, NASA Associate Administrator for Space Systems Development. This study of "national space launch requirements" was to focus on future access to space needs, and to develop various options for addressing those needs. Key to the study was the premise that the cost of putting payloads in orbit was too expensive, especially in light of the shrinking NASA and federal budgets. Thus, cutting the cost of getting into space was the study's bottom line. In addition, all launchers considered in the "Access to Space" study had to be capable of supplying a space station in Earth orbit.

Aldrich, assisted by Michael Griffin, then Associate Administrator for Exploration, divided launch system alternatives into three broad categories, called options. In Option 1, the U.S. would continue to rely primarily on the Space Shuttle through the year 2030. Option 2 examined a variety of expendable launchers as a possible Shuttle replacement beginning in the year 2005. Option 3, the most ambitious part of the study, considered the creation of a "next-generation" launch system using advanced technologies. The report of the Option 3 team was covered in the preceding Fact Sheet. Here, we will consider the conclusions of the Option 1 and Option 2 teams.

The Option 1 team, led by Jay Greene from the Johnson Space Center, Houston, Texas, looked at three alternatives for upgrading the Space Shuttle, while maintaining the existing array of expendable launchers. The first alternative, called "retrofit' Figure 1 , considered improving Shuttle subsystem technology, particularly in the Orbiter. Typical improvements included better main engine controllers, longer-life fuel cells, and new computers. No new Orbiters would be built (except to replace any lost through attrition); instead, these improvements would be installed on the existing fleet of Orbiters.

The second major alternative considered by the Option 1 team was substantial modifications to the Shuttle. These modifications would be incorporated into a new fleet of Orbiters. Hence, this alternative was called "new build" Figure 2 . Typical of the "new build" changes was the replacement of the hypergolic propellants in the orbital maneuvering system with an oxygen-ethanol propellant system. Being nontoxic, the oxygen-ethanol propellant would permit better ground operations. The third alternative examined by the Option 1 team considered even more radical Shuttle changes. These changes, such as the use of flyback boosters, required altering the Orbiter shape and replacing the entire fleet. The Option 1 team chose to analyze further the first two alternatives, based primarily on the extremely high cost of the third alternative.

The Option 2 team, led by Wayne Littles and Len Worlund of the Marshall Space Flight Center, faced the daunting task of analyzing 84 different expendable launch vehicle configurations, including all significant combinations of numbers of stages, engines, propellant types, means of accommodating cargo and crews, and an assortment of other variables. The Option 2 team used a methodical process to reduce to four the number of major launcher architectures under consideration.

The first major architecture, called 2A Figure 3 , retained the Delta and Atlas vehicles, but replaced the Shuttle and Titan rocket with a new, partially reusable vehicle. This new spaceship would include a cargo carrier, and it would have automated rendezvous and docking capability in order to resupply the space station. It also would serve to launch general payloads, and have a small vehicle for transporting humans into space. The 2A architecture minimized the size and number of new launch vehicles needed; however, it had only a limited capability to return items from the space station.

The second major architecture, called 2B Figure 3 , differed from the 2A architecture in three significant ways. A new vehicle capable of placing payloads weighing up to 20,000 pounds in orbit replaced the existing Atlas rocket, while a small (70% scale) Orbiter and new cargo carrier carried crew and cargo. These new cargo and crew carriers replaced the Shuttle and the Titan rocket. None of the 2B architecture vehicles were reusable. The 2B architecture could bring back all mass taken to the space station in the small Orbiter, and it lowered the cost of Atlas missions. However, it required large and costly new space vehicles.

The third and fourth major architectures, called 2C and 2D Figure 4 , were similar in that they called for the development of new expendable launchers to replace the Space Shuttle and the Titan and Atlas rockets, as well as development of separate crew and cargo carriers. The crew and cargo carriers were the same for both architectures. Their main difference was that architecture 2C used hybrid boosters and Shuttle main engines, whereas, architecture 2D used the Russian RD 180 and the U.S. J2S engines.

In addition to analyzing alternative launcher architectures, each of the three option teams had to select the one architecture that best met performance goals for the least number of dollars. We saw in the preceding Fact Sheet that the Option 3 team selected a rocket-powered, single-stage-to-orbit spaceship. The Option 1 and Option 2 teams also had their best launcher picks.

The Option I team selected the "retrofit" architecture because of its lowest costs for design, development, test, and evaluation, while still permitting about as much cost savings in operations as the other Option 1 architectures. Meanwhile, the Option 2 team selected the 2D architecture, mainly because it did not require development of a new engine, had low costs over the life of the launcher, and had the lowest operations costs for the Atlas-class missions, which had high commercial interest. In addition, like the Option 3 team, the Option 2 team recommended revolutionizing NASA's approach to operations in order to lower costs.

The reports of the three "Access to Space" study teams were submitted in July 1993. Then, the study steering group had to turn the three separate reports into a coherent set of observations, conclusions, and recommendations. In addition, the three teams briefed representatives of Rockwell International, Martin Marietta, and other aerospace firms at NASA's Marshall Space Flight Center on August 31, 1993. Also in late August 1993, a group from NASA's Marshall Space Flight Center, inspired by the work of the Option 3 team, and supplied with data from NASA's Langley Research Center, offered its own briefing on a program that promised to develop a single-stage-to-orbit spaceship. That program remarkably resembled the X-33 Advanced Technology Demonstrator program that would emerge the following year, but it had been put together in only two weeks.

Langley had been studying post-Shuttle space transportation since 1974. Gene Love was chief of the Center's Space Systems Division, which had recently been formed to support the Space Shuttle program by conducting aerodynamic analysis and tests of the design concepts to determine the vehicle's overall configuration, that is, would it be a single-stage or a two-stage vehicle? Or would it be a stage-and-a-half vehicle (the current configuration)? Those contractors vying for the Shuttle contract submitted their design concepts to Langley for testing, and NASA Headquarters turned to Langley for an objective aerodynamic analysis of those design concepts.

Gene Love realized that NASA would require a launch vehicle after the Space Shuttle, so he formed a small group to look at possible post-Shuttle (Shuttle II) vehicles. Love was influenced by a program called C/SGT, Continental/SemiGlobal Transport. The C/SGT vehicle would take off, almost attain orbit, then land, the object being to take people or cargo from any place on Earth to any other place on Earth in less than two hours. Gene Love realized that the C/SGT vehicle, with modifications, might become a single-stage-to-orbit vehicle. However, research would be necessary before that could take place. So, a small group in the Vehicle Analysis Branch of the Space Systems Division began studying single-stage-to-orbit vehicles, as well as two-stage vehicles, to determine what technologies were needed. Every five years or so, as new technologies became available, such as composite materials in airframes, cryogenic fuel tanks made of composites and other advanced materials (such as titanium aluminides), and new thermal protection systems, the Vehicle Analysis Branch redid these vehicle design studies.

In 1992, the Langley Vehicle Analysis Branch supplied data to the "Access to Space" Red Team, led by H. Lee Beach, Jr., NASA Langley's deputy director, as discussed in Fact Sheet #2. At that time, members of the Vehicle Analysis Branch, such as Richard "Dick" Powell, Theodore "Ted" Talay, Roger Lepsh, and Douglas Stanley, were working on a single-stage-to-orbit vehicle, whose origins lay in the Shuttle II studies initiated in the 1970s. That vehicle study was called the Single-Stage Vehicle (SSV), having undergone a name change from the Single-Stage-to-Orbit (SSTO) study, when the Strategic Defense Initiative Office (SDIO) made known its own Single-Stage-to-Orbit (SSTO) program to the Langley group.

The SSV had a cylindrical, winged body shape, like the Space Shuttle, and lobed fuel tanks, like the X-33, with a canister on top for carrying payloads. The design was left over from a Langley Vehicle Analysis Branch study conducted during the early 1980s, but it was too heavy. The Langley group was trying to reduce the vehicle's mass. The same members of the Vehicle Analysis Branch assisted both the Option 2 and Option 3 teams on NASA's "Access to Space" study, as well. The now extensive data acquired over the decades through the SSV and other design reviews were made available to a group from the Marshall Space Flight Center, headed by Gene Austin, who used the data to formulate a technology development and testing program for single-stage-to-orbit transport. That program was the X-2000.

Gene Austin, the individual chiefly responsible for formulating the X-2000 program, led the August briefing, assisted by Steve Cook, Larry Schultz, Donna Havrisik, and Roger Romans, all from the Marshall Space Flight Center. The X-2000 Advanced Technology Demonstrator, as the experimental flight test vehicle was labeled (for the program's final year of operation) Figure 5 , and the X-2000 program, were created outside the Option 3 team of NASA's "Access to Space" study, even though Austin and Cook currently were serving on that team. Nonetheless, the enthusiasm over the feasibility of a single-stage-to-orbit vehicle generated within the Option 3 team clearly was behind the Marshall move to develop the X-2000. Although the X-2000 project officially had no connection with NASA's "Access to Space" study, the project clearly would not have been conceived or attempted without the belief in the feasibility of single-stage-to-orbit transport fostered within the study's Option 3 team. Even so, looking at the project from outside NASA, it appeared that the X-2000 was an attempt to "capitalize on the excitement generated by the McDonnell Douglas DC-X experimental rocket," according to Ben Ianotta in the November 15-29, 1993, issue of Space News.

The X-2000 program did reflect current Pentagon interest in single-stage-to-orbit vehicles. The Department of Defense's Strategic Defense Initiative Office (SDIO), now known as the Ballistic Missile Defense Organization (BMDO), had an active single-stage-to-orbit spaceship program. In August 1993, as the X-2000 was being briefed to NASA Headquarters, the BMDO was test flying an experimental vehicle, the DC-X, built by McDonnell Douglas Aerospace. The DC-X, moreover, was not the final stage of the BMDO single-stage-to-orbit (SSTO) program. The program also called for the building and test flying of an experimental follow-on vehicle to the DC-X, called the SX-2 (Spaceplane Experimental). The official designation of the DC-X was the SX-1. The X-2000 program and flight vehicle specifically took into account the BMDO's SX-2.

The SX-2 Advanced Technology Demonstrator was expected to be flown within three years, using the same (but enhanced) engines, the same launch facilities, and the same control center, as the DC-X. Both the DC-X and SX-2 were suborbital vehicles. Unlike the DC-X, though, the SX-2 would test certain critical technologies needed for single-stage-to-orbit flight, as well as demonstrate the ability to cut operations, support, reliability, and other recurring flight costs. The rationale for funding the SX-2 program centered around not only certain military objectives, but the value to commerce of having inexpensive access to space, which was the ultimate promise of single-stage-to-orbit transport. The total SX-2 program cost was estimated by both the Pentagon and McDonnell Douglas to be $450 million, to be spent over the four-year period spanning fiscal 1994 through fiscal 1997.

The X-2000 was designed to be just a little bit more of a flight test vehicle than the SX-2. Both were suborbital single-stage-to-orbit technology demonstrators, but the X-2000 had a significantly larger weight (without fuel, known as GLOW) and was longer than the SX-2. Unlike the Pentagon's SX-2, though, the X-2000 required both a "NASA culture change" and cooperation with the Russians, from whom the engines might be obtained. Some of the tools for implementing that "culture change" would come from the aerospace industry and the Pentagon. In addition, the X-2000 would cost less then the SX-2, but be ready to fly in the same amount of time, 36 months
Figure 6 .

The SX-2 lay far in the future, however, and the DC-X only started its series of test flights on August 18, 1993. Col. Simon P. "Pete" Worden, SDIO Deputy for Technology, encouraged other Department of Defense agencies (such as the Advanced Research Projects Agency and the U.S. Air Force), the Department of Energy, NASA, or a combination of government agencies, to support the SX-2 as a program run jointly by the SDIO and the other agency. Not surprisingly, then, the proposed X-2000 program called for joint funding by NASA and the Department of Defense. The annual X-2000 program cost for fiscal 1996 through 2000 was $445 million. NASA was to contribute $225 million each year, with the Department of Defense supplying the remainder.

Despite the proposal to have the X-2000 program jointly funded by the Department of Defense and NASA, the X-2000 was just a NASA program. Indeed, it was conceived as strictly a Marshall Space Flight Center project. Take-offs and landings would take place at the Kennedy Space Center in Florida. The project, as described by Austin and others in their August 1993 briefings, would employ hundreds of NASA employees at both Marshall and Kennedy, with the participation of other NASA center employees "to be determined."

The X-2000 vehicle was to be transported from Marshall to the Kennedy launch site via barge, then flown suborbital over a range of 880 nautical miles over the Atlantic Ocean. Upon completion of a test flight, the X-2000 would return to Kennedy and land at the Space Shuttle facility, launch pad LC 34 or LC 37 Figure 7 . In case a flight had to be aborted, four Shuttle abort sites were available within range. Test flights from Edwards Air Force Base, the Shuttle spaceport in California, to the White Sands Missile Range in New Mexico, a distance of 583 nautical miles, also were considered, but those required risky overland flights.

The X-2000 would take off vertically, but land horizontally. Launches from rockets or the Shuttle were rejected, as they would by extremely costly and would not demonstrate program operations concepts. Launch from an aircraft, however, was rejected on several technical grounds, especially design complications and redundancies required for the aircraft to be piloted. Vertical take off and landing were rejected too, because the DC-X already was demonstrating that approach, and because vertical landing necessitated a critical, and as yet unproven, flip maneuver when the spaceship came in for a landing. In contrast, taking off vertically and landing horizontally was perceived to be the lower risk approach.

The X-2000 program sought to lower the cost of getting to space by focusing on simplifying operations, developing and testing critical technologies, and instituting a new management approach. The simplification of ground operations proposed in the X-2000 program echoed the "Access to Space" Option 3 team report, especially the operations section written by Gary Payton, and which in turn owed much to the influence of the SDIO SSTO program. The X-2000 program proposed setting up rapid preflight planning and turning the vehicle around quickly, while using only small ground and flight operations teams. The launch site (like that used for the DC-X) would be lightly staffed by a team limited to five or six performing the flight manager, systems engineer, communications, payload engineer, and voice and command duties.

Technology would play a key part in achieving the goal of low-cost, rapid operations .. The avionics and flight control software would permit autonomous flight operations, while system health monitoring systems, and on-board built-in test and diagnostic systems, would simplify and speed up vehicle check-out before and after flight. Global Positioning Satellite (GPS) updates would support autonomous ascent, flight, and landing (possibly using the Shuttle's autonomous landing design).

The X-2000 was conceived as an "Evolutionary Test Bed" to enable operational flight testing of critical rocket-powered, single-stage-to-orbit technologies. As a technology demonstrator vehicle, the X-2000 would test reusable fuel tanks and thermal protection systems, the materials used to protect spaceships as they reenter the atmosphere. The X-2000 fuel tanks would be similar to those required for an operational single-stage-to-orbit transporter, and would be tested several times under flight conditions to determine their reusability. The X-2000 fuel tanks would made of lightweight durable materials, such as aluminum alloys and composites. Also, the thermal protection system materials would be durable, reusable, and similar to those needed for an actual single-stage-to-orbit vehicle. Three candidate thermal protection systems were under consideration, one of which had been developed at NASA's Ames Research Center and had had extensive ground testing, but no flight testing.

The selection of engines for the X-2000 reflected the new possibilities opened up to the U.S. aerospace industry by the end of the Cold War. In December 1991, three Soviet republics (Russia, Ukraine, and Byelorussia) formed a commonwealth, effectively marking the dissolution of the Soviet Union and the end of the Cold War, which had been waged between the Soviet Union and the United States since the close of World War II. The X-2000 program called for initially using available engines that burned a combination of either liquid oxygen and liquid hydrogen or liquid oxygen and rocket propellant. Engine candidates included the liquid oxygen-kerosene NK-33 Russian engine available through the Aerojet firm in the United States. The NK-33 had been designed for the Soviet N-1 moon rocket, and the engines had been in storage since the late 1960s. Like the NK-33, the D-57A was designed for the Soviet N-1 moon rocket. It completed qualification testing in 1975, and was also available through Aerojet. The American RS-27A was more readily available than the NK-33. It was normally used as a Delta II booster engine. Rocketdyne manufactured the RS-27A, and it was then currently in production. However, the X-2000 team deemed the Russian D-57A to be the only viable liquid hydrogen-liquid oxygen engine, and chose to equip the X-2000 (on paper) with two RS-27A and two D-57A engines. Ultimately, though, Gene Austin wanted to outfit the X-2000 with a modified version of the Russian RD-701 tripropellant engine that burned hydrogen, oxygen, and kerosene. The Langley Vehicle Analysis Branch had shown in the 1970s the advantage of using a combination of propellants, such as hydrogen and kerosene, rather than just one or the other, but this choice of propellants gave rise to vehicle design complications.

The X-2000 team considered a lifting body shape for the X-2000, that is, the same aeroshell design currently used by the X-33, but rejected it Figure 8 . They found that the vehicle weight without fuel (the so-called dry weight) approached one million pounds, thereby making the vehicle too heavy to achieve altitude and speed goals. Also, the use of a lifting body did not appear to be feasible in terms of cost and meeting schedule deadlines. Instead, utilizing the data, namely the computational fluid dynamics analysis, supplied by the Langley Vehicle Analysis Branch, the X-2000 was a 96-foot-long (120-foot-long in some briefing charts) winged cylinder body. It had known, acceptable aerodynamic characteristics, and weighed (without fuel) about 400,000 pound, well within the vehicle weight goal Figure 6 . The X-2000 ship was about half the size of the envisioned full-scale single-stage-to-orbit operational vehicle, which was anticipated to use seven Space Shuttle Main Engines.

The most revolutionary aspect of the X-2000, as a NASA program, was its management approach. Just as the "Access to Space" Option 3 report had called for changes in NASA "culture" and a "new way of doing business," so the X-2000 program proposed to demonstrate "New Ways of Doing Business Within NASA." Among those new ways of doing business was adoption of the project management rules of Lockheed's Advanced Development Project, more popularly known as the Skunk Works. The original "Skonk Works" appeared in Al Capp's "Li'l Abner" comic strip, as a place where Appalachian natives combined skunks, old shoes, and other bizarre ingredients to concoct funky brews suited to a variety of purposes. The Lockheed "Skunk Works" has concocted such formerly secret aircraft as the F-80 Shooting Star, the first aircraft to win an all-jet battle, the U-2, the F-104 StarFighter, the SR-71 Blackbird, which still holds several world aircraft records for speed and altitude after more than three decades, and the F-117A Stealth Fighter, today famed for its performance in the 1991 Persian Gulf War (Operation Desert Storm).

Lockheed's Advanced Development Project operated according to a set of rules internally called Kelly's Rules after Skunk Works founder Clarence L. "Kelly" Johnson. Kelly's Rules were simple:

1. The Skunk Works manager must be delegated practically complete control of his program in all aspects. He should report to a division president or higher.

2. Strong but small project offices must be provided both by the military and industry.

3. The number of people having any connection with the project must be restricted in an almost vicious manner. Use a small number of good people (10 percent to 25 percent compared to the so-called normal systems).

4. A very simple drawing and drawing release system with great flexibility for making changes must be provided.

5. There must be a minimum number of reports required, but important work must be recorded thoroughly.

6. There must be a monthly cost review covering not only what has been spent and committed but also projected costs to the conclusion of the program. Don't have the books ninety days late and don't surprise the customer with sudden overruns.

7. The contractor must be delegated and must assume more than normal responsibility to get good vendor bids for subcontract on the project. Commercial bid procedures are very often better than military ones.

8. The inspection system, as currently used by the Skunk Works, which has been approved by both the Air Force and the Navy, meets the intent of existing military requirements and should be used on new projects. Push more basic inspection responsibility back to subcontractors and vendors. Don't duplicate so much inspection.

9. The contractor must be delegated the authority to test his final product in flight. He can and must test it in the initial stages. If he doesn't, he rapidly loses his competency to design other vehicles.

10. The specifications applying to the hardware must be agreed to in advance of contracting. The Skunk Works practice of having a specification section stating clearly which important military specification items will not knowingly be complied with and reasons therefore is highly recommended.

11. Funding program must be timely so that the contractor doesn't have to keep running to the bank to support government projects.

12. There must be a mutual trust between the military project organization and the contractor with very close cooperation and liaison on a day-to-day basis. This cuts down misunderstanding and correspondence to an absolute minimum.

13. Access by outsiders to the project and its personnel must be strictly controlled by appropriate security measures.

14. Because only a few people will be used in engineering and most other areas, ways must be provided to reward good performance by pay not based on the number of personnel supervised

The team putting together the X-2000 program took Kelly's Rules to heart and adapted them to the management of their project:

1. Head of skunk works must have practically complete control of the program in all aspects.

2. Project Office must be small but strong.

3. Co-locate key engineering, manufacturing, testing, and operations personnel.

4. Restrict the number of people having any connection with project; but, provide communication to Science &Engineering labs for support as needed.

5. Access by outsiders to the project and its personnel must be controlled through a project delegated buffer team.

6. Design methodology, requirements, and tailored specifications should be defined up front and not changed unless there is a positive and measurable benefit to the program.

7. Simple drawing and drawing release system with great flexibility for making changes; IDIT and FDR milestones.

8. Minimum number of reports required; simple tailored milestones.

9. Monthly cost reviews covering what has been spent and committed, in addition to projected costs to conclusion of the program.

10. Project must be delegated and assume more than normal responsibility and the procurement of hardware and other contracts needs to be streamlined.

11. Push back most basic inspection responsibilities to subcontractors and vendors; but check to make sure their procedures meet our requirements.

In addition to these management rules, the X-2000 program proposed to institute other approaches to a "new way of doing business" within NASA. One of those approaches was called Fast Track Acquisition and was used by the Ballistic Missile Defense Organization and its predecessor, the Strategic Defense Initiative Office Figure 9 . The key principles of BMDO Fast Track Acquisition included having a single manager under one agency empowered to make all decisions (within the law); forming a small program office; building hardware, not paper; focusing on key demonstrations, not everything; streamlining documentation and reviews (which also meant minimizing the number of engineering drawings); having the contractor integrate and test prototypes; and tracking cost and schedule in near real time. The X-2000 team summarized these BMDO rules of Fast Track Acquisition succinctly: "Break Reg's [sic], Follow Law.

In order to carry out the project faster and at reduced cost, the X-2000 program called for maximizing the use of off-the-shelf commercial and military components, as well as commercial quality standards. For example, all X-2000 software would be generated internally; all avionics would be purchased "off the shelf" with the exception of power distribution units, interface adapters, and cables. In addition, a way was found to procure services and components faster and cheaper, yet still within standard NASA practices. Project definition, design, and development would take place entirely at the Marshall Space Flight Center. The project would have no prime contractor. Individual procurements would be let out to competition, or acquired through sole source contracts, but only for purchases valued at under $200 million. Engines and other major components would be purchased through sole source contracts as much as possible. The X-2000 program briefing also included an alternative procurement scenario, although not as promising, in which an industrial prime contractor built the flight vehicle.

In order to get the X-2000 program started as soon as possible, namely in fiscal 1994, which started on October 1, 1993, that is, less than two months after the program briefing, congressional approval would be required to release a Request for Proposals, the first step in getting the program started. The X-2000 team felt fairly confident of the program's success, or at least hoped to electrify further excitement over the feasibility of single-stage-to-orbit transport, and they could see support for single-stage-to-orbit vehicles in Congress and among space activist groups. Congressional support included Dana Rohrabacher (R-Calif.), who served on the same House science subcommittee that annually deliberated the NASA appropriations bill, and Senator Pete Domenici, a Republican from New Mexico and member of the powerful Appropriations Committee. In June of 1992, the House Appropriations Subcommittee on Defense voted to kill the SSTO program. Before the full House voted, however, Rep. Rohrabacher talked John Murtha (D-PA), chairman of the Defense subcommittee on appropriations, into keeping the program. Thus, although that program's fatal budget woes still lay in the future, but not the too distant future, there was reason for hope and congressional support of a single-stage-to-orbit program, such as the X-2000, in August 1993.

In addition, several space groups energetically made known their support of single-stage-to-orbit vehicles, especially the DC-X. The existence of the Pentagon's SSTO program, renamed the Singe-Stage Rocket Technology (SSRT) program in early 1993, was not public knowledge until the first stories about the DC-X appeared in Business Week and Barron's on June 21, 1993, two months after McDonnell Douglas revealed the vehicle before the press on April 3, 1993. Then, the following fall, NBC Nightly News and CNN covered the flight of the DC-X on September 11, 1993. Up until then, the SSRT program lay buried in the SDIO, then BMDO, budget, which lacked the public attention given the NASA budget.

Much earlier, though, space activist groups, such as the Space Transportation Association, the Space Frontier Foundation, the National Space Society, and the Space Access Society, had been pressuring Congress to support the DC-X program. Key to starting the SSTO/SSRT program, of course, had been the Citizens Advisory Group for Space, an activist group organized by science fiction writer (and speech writer for California Governor Ronald Reagan) Jerry Pournelle (see Fact Sheet #1). During the summer of 1993, moreover, as the X-2000 program was being formulated, Henry Vanderbilt and the Space Access Society organized letter campaigns in support of $75 million of funding for the successor to the DC-X, the BMDO's SX-2.

The BMDO did not always welcome publicity, unlike its industrial partner McDonnell Douglas. At the National Space Society conference, held in Washington, DC, in May 1992, the BMDO thanked society members for their support in getting program start-up approval for fiscal 1992, but recommended not publicizing the program, since publicity might raise questions. In contrast, McDonnell Douglas, once awarded the DC-X contract, welcomed the free publicity offered by the National Space Society and other groups.

Although the X-2000 was not meant to be, it laid the foundation for a future NASA single-stage-to-orbit program, the X-33. Still, before NASA could commit to any kind of single-stage-to-orbit program, the results of the "Access to Space" study had to be addressed. Would NASA opt for an upgraded Shuttle fleet over the more technologically daring alternative of a single-stage-to-orbit vehicle? Or would the space agency instead develop a new generation of expendable launcher? Or again, would NASA pursue a combined fleet of Shuttle orbiters and expendable launchers? In addition, outstanding policy issues stood in the way, such as whether NASA and the Department of Defense would pursue a separate or a joint single-stage-to-orbit program. Finally, and not the least, was the question of funding a NASA single-stage-to-orbit program. These matters are taken up in the next fact sheet.