An artist's concept of Lockheed Martin's X-33 in space. Photo: NASA

NASA announced Thursday that it would not provide any additional funding for the X-33 or X-34 launch vehicle technology demonstration programs, effectively killing both projects before either made its first flight.

The decision came after NASA decided to refocus its attention on developing the technology for a next-generation reusable launch vehicle with new programs under the agency's Space Launch Initiative (SLI). NASA officials said they are in "competitive negotiations" with a number of companies for SLI contracts, but that neither the X-33 nor the X-34 would receive any SLI funding.

"NASA determined that the benefits to be derived from flight testing these X-vehicles did not warrant the magnitude of government investment required and that SLI funds should be applied to higher priority needs," the agency said in a statement Thursday.

NASA's contract with Orbital Sciences Corporation to build and fly the X-34 will be terminated on Friday, agency officials said. Funding for the X-33 was already set to run out at the end of the month when a cooperative agreement between NASA and Lockheed Martin expires.

Lockheed Martin could press ahead with the X-33 if it desired by using its own funds, although a company spokesman said Thursday the business case didn't support continued development without government assistance.

The X-33 program had cost NASA $912 million since its inception, while the agency spent $205 million on the X-34. In addition, Lockheed Martin contributed $357 million to the X-33 under the terms of its cooperative agreement in NASA, up from the $212 million it had originally committed to spend.

The X-33 program was restructured late last year in hopes of getting things back on track. But the program's future -- including the first flight of X-33 in 2003 -- hinged on NASA bringing the single-stage-to-orbit prototype into the Space Launch Initiative.

"We had been optimistic to get SLI money. So we are disappointed NASA decided not to do that," Lockheed Martin spokesman Evan McCollum said.

Both the X-33 and X-34 promised to test advanced technologies that could be used in future reusable launch vehicles (RLVs), but encountered major problems and delays. When NASA awarded the X-33 to Lockheed Martin in mid-1996, beating out rival proposals from Boeing and McDonnell Douglas, the agency had planned for the vehicle's first suborbital test flight to take place in March 1999. Problems with the vehicle's aerospike engine and hydrogen fuel tank, made of lightweight composites, continued to push that date back into 2000.

NASA had still hoped to fly the vehicle in mid-2000 when an accident damaged one of the hydrogen tanks during a November 1999 load test. After an investigation into the accident was completed last year, NASA and Lockheed Martin reached an agreement to replace the tanks with heavier, but more reliable, aluminum tanks, pushing back the launch until 2003. That agreement made it clear that if Lockheed Martin wanted any additional NASA funding for the project, it would have to compete for SLI money.

An artist's concept of Orbital Sciences' X-34 in space. Photo: NASA

The X-34 was also started in 1996 as an effort to test technologies for future RLVs. The air-launched vehicle had completed a number of captive-carry tests in 1999, where the vehicle remained attached to its L-1011 carrier aircraft during a test flight, before NASA and Orbital reviewed the program and concluded that additional emphasis was required on safety and reliability. This change required considerable additional money for hardware and tests that would have exceeded the program's budget. The extra money would have come from the SLI program, and as with the X-33, NASA decided that "the benefits to be derived from continuing the X-34 program did not justify the cost," according to a statement.

Art Stephenson, director of NASA's Marshall Space Flight Center, said that both the X-33 and X-34 may have failed because they were too ambitious. The X-33 in particular was originally meant to be a subscale model of VentureStar, a single-stage to orbit reusable launch vehicle proposed by Lockheed Martin. Although the designs of the X-33 and VentureStar diverged to a degree over time, the company planned to use some of the technologies tested by the X-33 into VentureStar.

"We have gained a tremendous amount of knowledge from these X-programs, but one of the things we have learned is that our technology has not yet advanced to the point that we can successfully develop a new reusable launch vehicle that substantially improves safety, reliability and affordability," he said.

Instead, NASA's focus will be on SLI. "It is a comprehensive, long-range plan to promote commercial development and civil exploration of space and provides the strategy and funding to enable at least two competing architectures for full-scale development of a 2nd generation reusable launch vehicle by mid-decade," Stephenson explained. "Through focused risk-reduction activities and risk-reduction technology development, we will make significant improvements in safety, reliability and affordability over the launch capability we have today. A new launch system that meets these goals could begin operating early in the next decade."

In a statement Thursday NASA officials said they were in negotiations with several companies for contracts funded under SLI to develop key technologies needed for future RLVs. Contract awards under the program could be announced as soon as April.

Lockheed Martin is competing for funds to develop other SLI technologies apart from the X-33 program, McCollum said.

SLI has a budget of $290 million for fiscal year 2001, while the 2002 budget proposal submitted to Congress Wednesday by President Bush calls for a 64 percent increase in the program to $475 million. The complete SLI program envisions spending $4.5 billion over a five-year span.

Spaceflight Now's Justin Ray contributed to this report.