In the wake of the Columbia disaster, NASA officials say they're accelerating plans to develop a $12 billion Orbital Space Plane that would ferry astronauts to the International Space Station by 2012 at a lower cost than the space shuttle can.
Designed to function more like a minibus than the truck-like shuttle does, the lightweight space plane would carry mostly human cargo and rely on rockets and other technology that NASA has developed.
The space plane might not look like a traditional plane at all, but more like an earlier generation of capsulelike craft that were launched by expendable booster rockets in the Gemini, Mercury and Apollo programs.
"We've been told to implement the plan," Dennis Smith, the National Aeronautics and Space Administration's program manager for the Orbital Space Plane, said yesterday.
"What we've been asking ourselves is if there is any way we can do anything to speed things up."
Smith briefed reporters on the space plane as investigators continued to study the disaster that killed seven astronauts when Columbia broke apart over Texas during re-entry Feb. 1.
Smith said the space plane would be no more than half the size of a shuttle, which has roughly the same dimensions as a DC-9 jetliner.
It also would cost far less to operate than the shuttle's $500 million per flight. NASA hopes the space plane would shave the cost of ferrying passengers to the station to $100 million per flight or less.
Smith said he expects a flying version of the space plane by 2010 and regular service two years later.
He also noted that the design specifications that NASA expects to release Tuesday might call for a capsule-shaped vehicle. Calling it a space plane "does not imply wings," he said.
A 27-foot-long, robotic concept prototype, the X-37, is scheduled for its first test flight in mid-2004.
The final version probably would ride into orbit on models of the Delta or Atlas rockets that NASA developed in the 1990s to launch communications satellites but shelved when the dot-com bust dried up the commercial space market.
NASA has ruled out building another shuttle to replace Columbia but plans to keep the three surviving shuttles, the Atlantis, the Discovery and the Endeavor, flying for another decade.
They are the only U.S. craft capable of carrying cargo into orbit and the only ones large enough to haul the equipment and building materials required to complete the $100 billion International Space Station, which has been in orbit since 1998.
With the rest of the shuttle fleet grounded until investigators determine the cause of the Columbia disaster, two American astronauts and a Russian astronaut who are living on the station are dependent on Russian craft for transportation and supplies.
The Russians have supplied the three-person Soyuz capsule, which is docked to the station as a lifeboat, as well as unmanned Progress rockets that ferry water and supplies. But Russia has told the United States that it doesn't have the money to build enough of either craft for long-range support of the station.
At best, NASA sees the Orbital Space Plane as an interim solution for supplying crews to the space station while it develops a more advanced ship that would be launched more like an ordinary plane and would be able to draw oxygen from the atmosphere instead of using heavy tanks of liquid oxygen.
Smith said yesterday that the Columbia disaster "validated" plans NASA announced in November to produce the passenger craft.
Critics called the program shortsighted.
"It lacks vision. It's a stopgap measure for NASA so it can fulfil short-term goals of supplying a space station, which has a limited life of its own," said Rick N. Tumlinson, president of the Nyack, N.Y.-based Space Frontier Foundation.
Tumlinson said the space plane would supplement a shuttle program that he called basically an "expensive government trucking service" that could be handled by the private sector.
NASA should focus instead on exploring the planets, he said.
"The space plane is part of an extension of a shuttle program that's been heading in the wrong direction," he said. "The goal should be to make space travel more routine, less costly and safer."
Bruce Mahone, director of space policy for the Washington-based Aerospace Industries Association, an industry lobbying group, defended NASA's plans.
He said that although the shuttle fleet is aging, the three remaining craft are constantly being upgraded and have years of service left.
None of them has flown the 100 missions envisioned for each when the shuttle program began in the 1970s, he said.
The space plane "will be much smaller than the shuttles, newer and more inexpensive if designed properly," he said. "It's a lifeboat for the space station."