Low Earth orbit is no farther from the ground than Philadelphia is from Washington. But in the first 30 years of the space age, human access to that "high frontier" has been a complicated, costly, high-tech affair -- the province of big government and big industry.

There are those who believe there's another way -- a low-budget, low-tech alternative for the rugged individualist.

Enter a hypothetical flying machine called the cislunar space cruiser. Betting against heavy odds, an independent Rosslyn engineer has developed a plan for a private corps of astronauts who could punch in after their morning coffee for a six- to eight-hour stay in orbit and be home for supper. The operation is designed to provide quick response at low cost -- an orbital SWAT team for hire.

The cruiser is shaped like a slightly squashed ice cream cone with a cluster of rocket nozzles at the ice cream end. It seats one or two people. A small, cheap, "dumb" booster rocket would deliver crew, cruiser and other equipment to orbit. The exact orbit wouldn't matter much because the cruiser's high maneuverability could get it to the right place to perform as a spaceborne utility infielder -- saving falling satellites, rescuing stranded astronauts, towing mother ships, clearing orbiting debris and the like.

At the end of a shift, it would simply fire its thrusters and, aided by an onboard computer, nose back into the atmosphere like a needle, its passengers protected from reentry heat by a thermal shell and cooling systems. As the low-drag space cone slowed to the speed of sound, it would pop out a small parachute.

Then, at about 25,000 feet, it would deploy a big cloth wing, known as a parafoil, of a type long used for landing military equipment. Using thrusters to power the cruiser forward, the pilot, like a skydiver, would pull lines on the parafoil to maneuver toward landing. The craft would make a zero-mph touchdown in an open field.

From the astronaut's perspective, the system is austere. In orbit, the cruiser would be unpressurized; the crew would in effect be on a spacewalk for most of their workday, scooting around with the cruiser's top down. Their "cabin" would be their spacesuits. Food-sticks and drink tubes would be mounted inside their helmets.

The crews would use Velcro to dock with other spacecraft, applied by peeling back a protective covering and slapping it on sticky-side-down. They might work outside the cruiser in stirrups or a side-mounted "slide-saddle," aided by equipment well-known to boaters, such as boat hooks. They would rely on onboard computers, radar and their own senses, having no vast army of ground controllers to call the plays.'Off-the-Shelf' Technology

This back-to-the-future design is the brainchild of Fred W. "Bud" Redding Jr., a self-employed systems engineer who works out of his home. He has plucked ideas from the Apollo program, on which he worked for Rockwell, a prime contractor, and from the submarine-launched missile program he worked on in the 1950s and other proven systems. The cruiser's conical, ballistic missile shape, Redding said, is a long-proven design that has reentered the atmosphere more than any other.

Two years ago, he and Thomas J. Flanagan, an airline pilot and retired Pan American World Airways president, formed the Cislunar Corp. to market the cruiser. (Cislunar refers to the region of space between Earth and the Moon.)

Redding's ideas have piqued the interest of several top space officials. Retired Air Force general James A. Abrahamson, former manager of NASA's shuttle program and head of the Strategic Defense Initiative who is now executive vice president of Hughes Aircraft, has served as an unpaid adviser. He described the design as "visionary, in the sense that it's way ahead of many peoples' thinking. . . . Bud has been working on a very simple idea at one end of the spectrum."

While it "still has some hurdles to get through," he said, "if you really need to get a person up there at low cost, and a launch system is available . . . this is the way to do it." He said its potential for rescuing satellites is "really fascinating."

"It's an extremely intriguing concept . . . looked at very little by the government," said Philip E. Culbertson, a former top NASA executive, now executive vice president of the External Tank Corp.

Part of the mystique of space flight is that it often uses the most advanced technology. "Bud just took {technologies} off the shelf and put them together," said Flanagan, Cislunar's president. "We want to go back to the old-fashioned entrepreneurial way, like the Wright Brothers and Henry Ford."

But rewards for entrepreneurs are iffy in the space business.

For example, Redding acknowledges that, to be practical, the cruiser requires a more substantial space suit and a more reliable, low-cost launch vehicle than any available. He is working on the suit problem with the same company that makes NASA's space suits. The lack of the booster is a major deficiency for the entire U.S. space program and several commercial efforts to develop one are underway.

Although there is no current market for the cruiser, Redding exhibits the faith and fervor of an inventor committed to his creation. "This is revolutionary. . . . Once it's available, there'll be a million ideas for using it." He said the cruiser could tend unmanned orbital laboratories and serve as a taxi, rescue and service vehicle for the planned U.S. space station, and for the existing Soviet Mir station.Keeping It Simple

The troubles of two satellites currently needing a reboost or in-orbit repair -- a $157 million communications satellite and a $1 billion spy satellite -- demonstrate the need for the cruiser, Flanagan said.

Cislunar is aiming, he said, for a price as low as $10 million per launch, compared with an estimated $300 million per shuttle launch. No space vehicle, though, has proved to be as cheap to launch as was originally claimed.

The design emphasizes low maintenance and a small infrastructure -- little more than a launch pad at one end and a truck at the other to bring the returned craft back to the pad, Redding said, and "a simplicity that translates into safety, safety, safety. My criterion is I want it to be safe enough that I can relax while my son flies it."

In contrast to the established tradition of multiple redundancy with its many backup systems, he said, "I eliminate the system, and then it doesn't need a backup." His cruiser, for example, has no wings, no landing gear and no hydraulics.

Redding worked on the idea originally under contract to the Pentagon's Defense Advanced Research Projects Agency (DARPA) in the early 1980s. When the government failed to pursue the idea, he began to refine it on his own.

"It struck my fancy at the time," said James N. Allburn, former project manager of DARPA's cruiser study, now vice president of SRS Technologies. "There were questions," he added, "but it sounded feasible. . . . It certainly would be a large step forward in capability if it were to be developed."