Space Exploration Technologies (SpaceX) is asking NASA to help fund the demonstration of a reusable space capsule the El Segundo, Calif.-based company has been developing in secret with its own funding for the past 18 months.

SpaceX President Elon Musk said the capsule, dubbed Dragon, is a “mix between Apollo and Soyuz” and is being designed to ferry cargo and crew to and from the international space station (ISS) starting in 2009.

The Dragon capsule is the centerpiece of the proposal SpaceX submitted March 3 under NASA’s Commercial Orbital Transportation Services (COTS) demonstration program. As many as 25 teams were expected to submit bids by the deadline for all or part of the $500 million NASA plans to spend through 2010 to help bring to market new services capable of taking over some of the space shuttle’s station duties by the time it retires.

Musk said SpaceX is going after “more than half and less than all” of the $500 million NASA has put on the table, but SpaceX is not going after it alone. The SpaceX COTS team consists of a half-dozen companies, including MacDonald Dettwiler and Associates Ltd., the Canadian firm that built the international space station’s robotic arm. That same arm, Musk said, would be used to grapple Dragon and berth the capsule to the station.

“All we have to do is position Dragon within reach of the station arm,” Musk told Space News. “This simplifies matters considerably, minimizes the danger of station impact and allows transfer of large objects through the common berthing mechanism.”

Dragon would maneuver within reach of the arm with the aid of a MacDonald Dettwiler-provided automated-last-mile-guidance system that uses light detection and ranging instrumentation, or LIDAR.

Other SpaceX teammates include Houston-based Spacehab, ARES Corp. of Burlingame, Calif., Odyssey Space Research of Houston, and Paragon Space Development Corp., a Tucson, Ariz.-based firm that also is helping Lockheed Martin with its Crew Exploration Vehicle life-support system design.

Neither Dragon nor its Falcon 9 rocket is ready to roll out to the launch pad. But the Falcon 9 is in development for a 2007 debut and some Dragon hardware — including a full-scale working prototype — already has been built.

“As part of a top secret project, we’ve already built a prototype flight crew capsule, including a thoroughly tested 30-man-day life-support system, which is sitting on our factory floor right now,” Musk said. “It doesn’t meet all the NASA requirements, so it will probably not see flight, but it has served as a valuable learning experience.”

The prototype lacks a reaction control system for maneuvering in space and a heat shield that would prevent it from burning up upon re-entry, Musk said, but could otherwise be launched into space.

At 3.6 meters in diameter, Dragon would be smaller than the 5-meter diameter Crew Exploration Vehicle. But then Dragon is only intended for comparatively short jaunts to the space station, not longer expeditions to the Moon and points beyond.

SpaceX began working on Dragon in late 2004 but has kept the project a closely guarded secret — a different approach for a company that has openly detailed on its Web site every step and misstep of the Falcon 1 development.

Musk declined to say how much he has spent on

Dragon so far, but said it was only a small part of the $100 million he has invested in SpaceX to-date building the Falcon 1 and getting started on the larger and more powerful Falcon 9.

Musk said SpaceX would continue to work on Dragon regardless of what happens in the COTS competition, but said NASA’s support would allow the company to move the project to the front burner.

“What COTS really allows us to do is dramatically accelerate our plans for manned spaceflight and make sure it is something that meets NASA’s requirements for crew and cargo service to the station,” Musk said.

Musk said he thinks Dragon can be ready to enter service in 2009 — a full year before the shuttle is expected to conduct its last flight.

“I feel very confident about being able to offer NASA an ISS-servicing capability by 2009 and am prepared to back that up with my own funding,” Musk said.

Dragon’s initial test flights would be conducted from SpaceX’s island launch facility in the Kwajalein Atoll, Musk said, with operational flights to be conducted from Cape Canaveral, Fla.

Musk said SpaceX proposed several different configurations of Dragon in order to meet NASA’s needs to deliver both pressurized and unpressurized cargo loads to the station and bring some materials back. He also proposed a crewed version capable of carrying up to seven astronauts to and from the station.

Musk indicated that he sees no problems meeting the aggressive timelines NASA has established under the COTS program.

“Development-schedule risk with Dragon is as much a function of NASA as it is SpaceX given all the ISS-visiting vehicle requirements, but I think we can get it done in another three and a half years,” he said.

“It took SpaceX just over three years to build both a company and a rocket from scratch, including engines, structure, avionics, two launch sites [and to get through the] regulatory crud,” he said. “If we hadn’t been forced to go to Kwaj[alein], we would very likely have launched by now. As it is, total time from zero to launch will be just over three and a half years.”

Musk, who started SpaceX in 2002 using the fortune he made selling his company PayPal to eBay that same year, has built a small satellite launcher dubbed the Falcon 1 that is being readied for its maiden flight from the Kwajalein Atoll site. SpaceX has scrubbed three attempts to launch the two-stage, liquid-kerosene-fueled rocket since late November and intends to make the next attempt March 20.