Technology Review surveys the burgeoning field of privately funded space launch start-ups.
Of course, people have tried for decades to realize the vision of a reusable rocket plane, with little success. “Rocket science has become synonymous with advanced technology, but the fact of the matter is that there has been very little in the way of new development of rockets since the early 1960s,” says Xcor Aerospace president Jeff Greason, a former Intel executive. What’s different now, he and others say, is that even before Columbia broke apart on February 1, people were actually starting to build and test new designs. Indeed, more than two dozen companies worldwide, not to mention NASA and other national space agencies, are actively developing rocket planes. And with the loss of the Columbia, deaths of seven astronauts, and subsequent grounding of the remaining shuttles, both the number of developers and the urgency of their task are likely to grow. “The need to find some way to get new technologies and new approaches to space transportation is probably a lot clearer than it was before,” Greason says.
Mojave, CA, Friday, July 12, 2002: XCOR Aerospace announced yesterday that its EZ-Rocket flew twice in one day. The flights were in preparation for the first air show flight of the EZ-Rocket at EAA AirVenture 2002 in Oshkosh, WI later this month. In addition to flying twice in one day, the EZ-Rocket performed two mid-flight engine restarts during each flight, another first for the EZ-Rocket.
The plane took off at 8:00 AM and performed a series of steep climbs while making multiple passes over the Mojave Airport. After the morning flight the EZ-Rocket was brought back to the hanger for refueling. "We were able to reload propellants quickly by cryogenically chilling our helium that is used to pressurize the propellant tanks," said XCOR Rocket Engineer Doug Jones. "Typically, as we load helium, its temperature rises through compression heating. Chilling the helium during loading negates this heating and allows us to get a full load onto the EZ-Rocket quickly."
At 1:15 PM the EZ-Rocket was rolled back out to the runway and made its second flight of the day with Dick Rutan at the controls. The EZ-Rocket performed another series of tight turns, steep climbs, and a wingover maneuver. "It was a zero-defects flight," said test pilot Dick Rutan. "It's quite pleasant to fly with that much power. It reminded me of my days in the military flying high performance jet fighters with afterburners. I am confident we'll be able to put on a great show at Oshkosh."
The EZ-Rocket, a modified Long EZ plane piloted by retired Lt. Col. Dick Rutan, flew two flights in one day earlier this month. Rutan's brother Burt Rutan, of Scaled Composites, designed the Long EZ plane and is also developing a separate reusable vehicle as part of the $10 million X-Prize competition to put three people in space and return them safely.
Xcor expects to be able to extend their upcoming Xerus design to make it capable of delivering microsatellites into low Earth orbit.
In this configuration, our suborbital vehicle would function as a reusable first stage that carries an expendable upper stage. Our vehicle releases the upper stage, which has its own rocket engine and is capable of putting a microsatellite into low Earth orbit. This vehicle will service the current small payload market as well as customers who today are not in the satellite launch market for reasons of expense and lead time.
Currently existing satellite launch vehicles do not allow for quick turnaround experiments. Not even the military has rapid and responsive access to space. Microsatellites almost always are launched as secondary payloads that are tied to the schedule of the larger primary payload. Although this is currently a small market, we think it has a large potential for development. Electronics miniaturization and diminishing size and power needs means that the next generation of certain kinds of satellites need not be as large as current models.
The Pathfinder is a sub-orbital propellant-transfer spaceplane. The configuration is a two-seat fighter-bomber-sized aircraft powered by two turbofan engines and one kerosene/oxygen-burning RD-120 rocket engine. The Pathfinder aircraft is designed to take off with its turbofan engines, and climb to approximately 30,000 feet where it meets a tanker aircraft. The tanker then transfers about 150,000 pounds of liquid oxygen to the Pathfinder spaceplane. After disconnecting from the tanker, the spaceplane starts its rocket engine and climbs to 70 mile altitude and Mach 15. By this time, the spaceplane is outside the atmosphere and can open its payload bay doors, releasing the payload with a liquid rocket upper stage, which delivers the payload to its intended low-earth orbit. The doors are then closed and the Pathfinder aircraft reenters the atmosphere. After slowing down to subsonic speeds, the turbofan engines are restarted and the aircraft is flown to a landing field.
The efforts of these private companies are more reason for optimism about the future of space travel than anything that NASA is currently doing. These companies are free of the complex bureaucracies of NASA and of the big aerospace firms. Their engineers can make purely engineering judgements. Lots of companies translates into the trying out of lots of new designs. Their pursuit of the sub-orbital space tourist market will, if any of these companies produce a working production craft, provide them with revenue from their first generation designs to fund development of successive generations.
|Share |||Randall Parker, 2003 February 08 07:48 PM Airplanes and Spacecraft|