Lockheed told to start building prototype of 8,700-mph plane Pilotless X-33s planned to fly by July 1999

Air travel

November 01, 1997|By Greg Schneider | Greg Schneider,SUN STAFF

NASA admitted yesterday that the X-33 space plane will probably not go as fast as planned, but gave Lockheed Martin Corp. clearance for final construction of the $1 billion craft.

Engineers at Lockheed Martin's fabled Skunk Works design shop in California have struggled all year with the weight of the plane, which will be asked to perform unlike anything ever made.

The X-33 is the small-scale prototype of a craft that will take off like a rocket, fly into space and return to Earth like an airplane -- all without the external fuel tanks or disposable parts that help make the Space Shuttle so expensive.

Lockheed Martin won the $1 billion contract last year to put a pilotless X-33 into flight by July 1999, aiming for a fleet of full-size vessels that will replace the Space Shuttle.

In testing the concept with the X-33, NASA originally wanted Lockheed Martin to make a craft that could go 15 times the speed of sound, or Mach 15. Now the space agency has decided that it can get by with Mach 13.

"Instead of going back through and trying to do a completely new design cycle, the lessons we set out to learn from the X-33 can still be done with this vehicle at Mach 13," said Gene Austin, NASA's X-33 program manager.

Even that speed, roughly 8,700 mph, would be four times faster than the official airplane record of 2,193 mph set by an SR-71 Blackbird in 1976.

Lowering the requirement shows "a thankful willingness to be honest about what the program can and cannot do at this stage," said Brett Lambert, an aerospace expert with DFI International. "If anything, it is an injection of realism that is far too often not seen in these programs."

Austin said Mach 15 -- which would amount to between 10,000 and 11,000 mph -- was desired primarily for testing the vehicle's heat shield. Other operational and technological tests can be accomplished at the slower speed, he said.

Designers working to reduce weight and thereby increase speed will move on to planning for the full-size orbital vehicle that will one day follow the X-33, he said.

That craft, called the Reusable Launch Vehicle, will have to reach Mach 25 to get into orbit.

The fact that designers can only get half that speed out of the smaller prototype demonstrates that achieving the goal is "a monumental challenge that should not be understated," Lambert said.

NASA's own efforts to design such a craft -- the National Aero-Space Plane -- ended in failure a few years ago partly because engineers could never figure out how to make it light enough.

Still, analysts pointed out that the X-33 program is just over a year old.

"This is a long-term program; there will be a lot of things that happen and change," said Marco Caceres, a space expert with the Teal Group.

"NASA doesn't even have an exact estimate of how much this program is [ultimately] going to cost. I've heard estimates from $10 billion to $20 billion, so clearly every step along the way, there are going to be compromises."

Weight isn't the only nagging issue. Wind tunnel tests revealed a stability problem during the spring, and engineers spent several months redesigning parts of the craft to compensate.

The delay meant postponing the final Critical Design Review from July until this week.

A panel of experts from NASA, Lockheed Martin and other companies spent the week going over the program before issuing a vote of confidence yesterday.

Austin, the program manager, said he hadn't expected any surprises.

"We've had reviews of all the major subsystems and components of the vehicle during the course of the last 10 months. This was the culmination, so the problems we have encountered during the course of this year have all basically been solved," he said.

Just yesterday, Lockheed Martin and NASA conducted the first flying test of the plane's unique rocket engine, called a linear aerospike for a design that relies on outside air pressure to shape the exhaust instead of traditional bell-shaped nozzles.

A one-tenth scale version was mounted on an SR-71 yesterday and flown at Mach 1.1.

While the engine was not powered during the flight, the test demonstrated its aerodynamic qualities, said Skunk Works spokesman Ron Lindeke.

NASA and Lockheed Martin are counting on the engine to put payloads into space for one-tenth the cost of a Space Shuttle launch, or $1,000 a pound instead of the shuttle's $10,000 a pound.

While NASA is funding most of the development of the X-33, the ultimate fleet of full-size vehicles is to be paid for by Lockheed Martin as a commercial venture.

Industry analyst Wolfgang Demisch, of B. T. Securities, said he has faith that the approach and the technology will work by early in the next decade.

"Lockheed will be a company which will have powerful cash generation and a sizable franchise in space," Demisch said.

"Assuming they don't find any obvious show-stopper, it seems to me this technology is sufficiently plausible that it will get implemented."

Pub Date: 11/01/97

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