Spacecraft, Delta Clipper, Photo, Copyright David H. Kaplan, 1993
(Image © David H. Kaplan, 1993)
The Delta-X Demonstrator sits on its launchpad waiting for another flight. Though the program was closed down following a strut failure and subsequent fuel tank crack, its viablilty had already been demonstrated. Maybe this is a good time to bring it back. - Ernest Lilley, Editor, SFRevu.

Opening Space for the 21st Century
by Yoji Kondo & William A. Gaubatz
(image credits: Credits: Book: Signet, DC-X: NASA, RLV Technology Program)

Robert A. Heinlein put it so eloquently when he said, "Reach low Earth orbit and you are half way to anywhere in the solar system". The orbital velocity for a typical low Earth orbit (LEO) is around 8 km/s. The escape velocity from Earth's gravity is about 11.2 km/s, so that roughly an energy twice that of a typical LEO flight would be sufficient for space ship to reach any destination in the solar system.

The Man who Sold the Moon 1970sAt the moment, we use mostly throwaway rockets for launching payloads into LEO and beyond. This is neither a very economical nor safe way to conduct business, as you are throwing away the expensive space vehicle after only one use and every launch is a first time event. For comparison, consider the following example. If you built a Boeing 747, flew it to Paris, and then junked it, imagine how much an airline ticket would cost to fly across the Atlantic! How safe would you feel knowing that your airplane had never been test flown before you boarded? Instead, if you built a spaceplane which could take your payload and passengers to LEO, then return to the ground to be readied for another flight with a ground crew comparable that used for keeping a 747 flying, the cost would only be about three times that of the fuel required to reach LEO and your spaceplane would have many hours of safe flights before yours. To reach LEO, we need fuel equivalent to that of reaching Mach 25, or 25 times the speed of the sound, which is roughly the cost of flying your plane from New York to Sydney, Australia. The cost may ultimately be reduced by two orders of magnitude, from some $20,000 per kilogram for the Shuttle to $200 per kilogram. See, for example, the opening article by Dan Goldin, then NASA Administrator, in “Space Access and Utilization beyond 2000” Edited by Y. Kondo, C. Sheffield and F. Bruhweiler, Univelt (American Astronautical Society’s Publisher) 2001.

It is true that we reuse the Space Shuttle, but the Shuttle is not exactly a spaceplane in the sense used above; rather, it is a re-buildable space ship. It takes several thousand people to service the Shuttle for re-flight and also takes a large number of operational personnel on the ground during its flight. The original Space Shuttle as envisaged and proposed by Werner von Braun was closer to our definition of a spaceplane, but various factors intervened, and what eventually emerged was the present Space Shuttle. It costs a few hundred million dollars to launch a Shuttle mission, and it takes a few months to ready it for re-flight; but, it does have the highest reliability record of all current launch vehicles.

Picture from the Space Age Multi-media Encyclopedia, Computer Support CorporationSeeing the necessity for developing a truly reusable and economical space ship to reach LEO, Dan Graham (retired Army General and former director of the Defense Intelligence Agency), Jerry Pournelle (President, Citizens’ Advisory Council for the National Space Policy -- Robert A. Heinlein was an active participant in this Council), and Max Hunter (the designer of the Thor rocket) visited Vice President Dan Quayle at the White House in 1989. After the impassioned and persuasive presentation by the three, the VP agreed to support an array of space-based initiatives, including the development of DC-X, as part of the Strategic Defense Initiative. President George H. Bush strongly supported the initiative, which began under the leadership of his predecessor, President Ronald Reagan. The Delta Clipper (DC-X) program was born out of the SDI Office program. DC-X was designed in such a way that it would be reusable like an airplane with a quick turnaround, within a day—if not within a few hours. It was also designed for operation by only three operators and maintained by a dozen technicians. The DC-X was built under contract at McDonnell-Douglas; Bill Gaubatz was the Project Manager responsible for designing and building DC-X.

DC-X was remarkable in the sense also that it was built on schedule of two years and within budget. The first version of DC-X was designed for sub-orbital flight to verify the operations technology; the orbital version was to follow as the second generation. Its first successful flight took place in 1993. Its series of flight envelope expansion tests culminated in demonstration of the total flight take-off and landing sequence including in-flight rotation to land repeatedly and safely on its base (just as Robert Heinlein said it should) and a rapid turn-around between flights of just eight hours.

Photo of DC-X launchFollowing eight successful flights, the DC-X was taken over by NASA and it was renamed by Dan Goldin the “DC-XA Clipper Graham” program to honor General Graham. The DC-XA successfully demonstrated numerous new technologies during both ground and flight tests and continued to verify airplane type operations. Unfortunately, in 1996 there was an undiscovered maintenance error that caused the space ship to tip over at landing; as a result, the fuel tank cracked. At that time, NASA was investing heavily in the VentureStar in partnership with Lock-heed-Martin, and could not find the funds to rebuild and continue the DC-XA.

Unlike the Delta Clipper, which was a technology flight test vehicle, the VentureStar was developed as a fully-blown prototype of a reusable launch vehicle (RLV), involving not-as-yet tested technologies and engineering concepts. The VentureStar was viewed as a replacement for the aging Space Shuttle fleet. The VentureStar could not meet the performance, cost or schedule design goals, and was canceled in 2001. X-34, another RLV program at NASA, too was canceled in the same year.

Presently, efforts to develop spaceplanes are to be found mostly in the private—‘entrepreneurial’—sector. The recent meeting of the Space Access Society, presided over by its president, Henry Vanderbilt, featured several private companies vigorously pursuing the dream of realizing economical access to LEO. For further information on the SAS conference in April 2002, you are referred to their website: In the year 2000, the private investment in space (in the U.S.A.) already exceeded the government expenditures. The examples of private sector activities in space include telecommunications, Earth resources, weather forecasting, and geo-positional sensing. All this was happening without the cost reduction that could result from the realization of economical reusable vehicles.

Once the cost of reaching LEO is reduced substantially—by a factor ten to a hundred—with spaceplanes, the private sector involvement will flourish far beyond the present activities. Commercial space tourism, which has seen its beginning with the flight of Dennis Tito in 2001, can become a booming industry; frequent flights for commercial tourism would bring down the cost of reaching LEO even further, making many other enterprises practical and profitable. For example, industrial scale solar power satellites will become a realistic proposition as a good solution to the declining terrestrial energy resources.

Perhaps, the best way for the Federal government to help make all that happen would be for its agencies, such as NASA, Air Force Space Command and the Navy Space program, to help develop, test and prove the basic operations and safety technologies of the sort under development with the now defunct DC-X program. Investing in the basic spaceplane engineering and flight demonstrations is a role fitting for the Federal government; the private sector as well as the government agencies would derive considerable benefits, economically and in national prestige. Investing large sums of funds -- in the range of tens to hundreds of millions of dollars—in basic spaceplane technologies is not a role that Wall Street investors will undertake. Once basic operations and safety technologies for spaceplanes are validated through repeated flight testing, all types of prototypes to suit diverse purposes in space would be built by the private sector. The space program would initiate a new economic sector based on space industries derived from new orbital and terrestrial infrastructures.

This new space business will create new wealth, new jobs and a viable source of new tax revenues. Now is the time to support the funding for many new DC-X type programs!

Some relevant articles by other authors who share an interests in Space and SF:

The SSX Concept by Jerry Pournelle

Will the Delta Clipper Turn Deep Space into Cyberspace?
by Paul Levinson (Wired, Feb 1994)

Want to help get us back into space? Write the a letter. If you've never written your senator or congressman and have ever bemoaned our lack of space initiative, whose fault is it?
Letters count more than email, but go ahead, send both.
Find your senator:

You can find out more about getting us into space at the Space Access webpage:


About the authors:

Dr. Yoji Kondo - Yoji Kondo, was President of International Astronomical Union Commission on Astronomy from Space. He has published over 200 scientific articles and has edited 12 books including "Space Access and Utilization Beyond 2000". As Eric Kotani, he has written several science fiction novels including "Legacy of Prometheus" with John Maddox Roberts. He also edited "Requiem: New Collected Works by Robert A. Heinlein and Tributes to the Grand Master" and is a director of the board for the Heinlein Society. An asteroid (#8072) has been named Yojikondo in recognition of his contributions to astronomy and the space program.

Dr. William A. Gaubatz - Dr. Gaubatz is co-founder and President of SpaceAvailable, LLC, a company creating virtual space adventures to bring space to people until we can bring people to space. As president of SpaceClipper International, he is pursuing development for commercial spaceplanes that could be certified for routine passenger travel. At McDonnell Douglas he originated and managed the DC-X/XA experimental programs and participated in pioneering efforts investigating physiological and psychological system requirements for space tourism. He is Chairman Space Tourism Society, a member of X-Prize Committee, Associate Fellow of AIAA, a member IAA and ISSL and Honorary member of the Japanese Rocket Society.

© 2002 Ernest Lilley / SFRevu