NASA's vision of private enterprise partners filling the cargo and crew launch gap left by the imminent retirement of its Space Shuttle fleet got a further boost from Orbital Sciences's successful 17 December long-duration test firing of its liquid-fuelled Aerojet-supplied AJ26 rocket engine.

A pair of liquid oxygen/kerosene-fuelled AJ26s will power the first stage of its Taurus II space launch vehicle - and carry its Cygnus cargo vehicle to the International Space Station, possibly before the close of 2011.

The AJ26 engine test ran for 55s at NASA's Stennis Space Center in Mississippi, during which the engine was purposely stressed to 109% - about 370,000lb (1,645kN) - of its baseline thrust level. Orbital also tested engine start-up, propellant valve commanding, the gimballed thrust vector control and shutdown sequencing, all with positive results according to preliminary data.

Oribital's successful engine test followed just days after a much-lauded test launch for competitor SpaceX, whose Dragon capsule became the first successful commercial space vehicle when it lifted off aboard the California-based company's Falcon 9 on a mission co-sponsored by NASA.

The launch, the second for the Falcon 9 two-stage-to-orbit rocket, was intended to prove the structural integrity of the Dragon spacecraft and its on-orbit operation, re-entry, descent and splashdown in the Pacific Ocean. By all accounts the flight was a success, particularly for a first outing.

SpaceX and Orbital are both flying under NASA's Commercial Orbital Transportation Services (COTS) programme, aimed at spurring growth in the commercial space industry and facilitating the birth of a private space cargo industry. SpaceX holds a $1.6 billion chunk of the COTS deal with NASA for 12 cargo delivery missions to the ISS; Orbital's side is $1.9 billion for eight ISS missions.

Orbital's push to its first Cygnus launch now involves a third and final firing of the first stage of the new rocket scheduled for January 2011 with three more AJ26s scheduled for testing over the next five months. As they are tested, the boosters will migrate to the Taurus II integration site at NASA's Wallops Flight Facility in eastern Virginia, from which a COTS demonstration mission is scheduled to fly late this year.

Orbital is doing exactly what it set out to do when it was founded in 1982 by David Thompson, Bruce Ferguson and Scott Webster: commercialising space. "This type of work is right up our alley," says Orbital's Barron Beneski.

At the same time it is steadily marching forward on cargo delivery to the ISS, Orbital is working on getting humans there as well. The company is in the thick of NASA's Commercial Crew Development (CCDev) effort, signing Virgin Galactic on as a partner in the second round of competition for NASA seed money to develop commercial human spacecraft that can deliver crews to the ISS. The US space agency is offering $200 million in this round.

"CCDev and COTS, they go hand in glove," says Beneski "You need cargo because there will be crew up there; you need transportation for crew now that the Shuttle is retiring."

Orbital's concept for a spaceplane entry in the CCDev contests builds on earlier NASA testbeds like the HL-10. Thales Alenia is building the pressurised crew compartment, and Northrop Grumman will develop a composite airframe for the proprietary "blended lifting body" developed by Orbital.

The company also has an expanded role for the Taurus II in mind. In addition to its work with NASA on cargo delivery, Orbital is also offering the Taurus II rocket to US civil government, military and commercial customers for dedicated launch services for medium-class satellites, the company says.

From its Wallops launch site, Taurus II will be capable of supporting mid-inclination and polar orbiting spacecraft weighing about 4,765kg (10,500lb) and 2,500kg, respectively. Development of a West Coast launch capability is planned for the future, focusing on higher-inclination orbits.

Expanding uses for Taurus II would not be possible, however, without NASA investment. The company is well aware space is not a market that will be completely commercially dominated in the near future, as private companies need NASA not only as a customer, but also for its expertise.

"Commercial companies cannot do this without NASA," he says. "They have terrific resources, personnel, expertise that are absolutely essential to moving to a different way toward accomplishing a mission of low-orbit transport. We'd like to be prepared to address those markets when they emerge. For those markets to emerge, there has to be a reliable transportation."

Source: Flight International

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