Orbital Sciences is scrambling to find a liquid-propulsion rocket engine that is in production and available for export to the U.S. to pave the way for its new Antares rocket, the centerpiece of a bid to compete for commercial and government work for decades to come. But just as NASA is finally turning to commercial launch providers, the Virginia-based company is running into roadblocks that jeopardize the rocket's future after only one launch.

Orbital hopes to sell Antares well beyond the 16 missions it has already won through NASA's first Commercial Resupply Services (CRS-1) contract. But, industry officials say the company must solidify a propulsion path by early next year in order to compete for the next batch of CRS missions for NASA. That contract is potentially worth billions and would help keep Antares in production as Orbital chases its ultimate goal of winning contracts to launch U.S. military and intelligence satellites.

The NK-33 engine that powered Antares' first flight was built decades ago by Russia's Kuznetsov Design Bureau and is no longer in production. Further, Orbital is uncertain about the quality of Aerojet's remaining stockpile of 23 NK-33s, beyond those set aside for NASA's CRS-1. Aerojet Rocketdyne is Orbital's primary subcontractor and overhauls the old NK-33 engines into a configuration for Antares, dubbed AJ-26.

Orbital officials say its only current alternative is the RD-180 engine made in Russia by NPO Energomash. But the United Launch Alliance (ULA), which operates the U.S. Air Force's Atlas V and Delta IV fleets, holds exclusive rights in the U.S. to buy the RD-180.

Over the last four years, Orbital has inquired about purchasing the RD-180 from ULA, RD Amross and Energomash. “We could never get to first base on that,” says Michael Hamel, the company's senior vice president of corporate strategy and development. Requests for support from the Air Force, Office of the Secretary of Defense and Congress were also met with silence, company officials say.

They suggest that these roadblocks amount to anticompetitive practices by ULA, which holds a monopoly for large government launches and uses the RD-180 to power the Atlas V Evolved Expendable Launch Vehicle (EELV).

Sparked by Orbital's concerns, the U.S. Federal Trade Commission is investigating whether ULA's exclusive arrangement with Russia's RD Amross violates antitrust laws.

But, the company is not waiting for the outcome of this review to move forward. Officials are already reviewing alternatives, though the only viable option is currently the RD-180, Hamel says. Orbital has also looked at the RD-181, RD-191 and RD-193. These are either still in development, or not yet approved for export. The RD-191 is the propulsion system being developed for Russia's Angara rocket.

Meanwhile, worried about losing its exclusive business with Antares, Aerojet Rocketdyne's president, William Boley, is offering to restart NK-33 production with Kuztnetsov. Boley says in order to start deliveries as soon as 2016, when NASA's CRS-2 contract moves forward, he would need to have a deal with Orbital by this fall.

The total production rate depends on the demand for Antares, but Boley says it is likely to be at least 4-6 engines annually. The strategy is to use the new engines for Antares as quickly as possible, and draw from the remaining 23 NK-33 engines requiring overhaul as a “buffer” if problems arise in restarting the production process, says Boley.

Hamel says that unlike upstart Space Exploration Technologies (SpaceX), Orbital does not intend to compete against ULA in the large-payload market. Antares is designed to reopen a market once served by the workhorse Boeing Delta II, which was used to launch GPS and defense weather satellites in the 1990s.

If successful, Antares could impact more than just the business of other launch providers by opening the door for satellite manufacturers to take advantage of new technologies to build smaller, but equally or more capable spacecraft, Hamel says. Such a shift could also threaten traditional defense and satellite manufacturing by large primes, such as Lockheed Martin and Boeing, who sized their spacecraft to utilize as much of the available volume and thrust of these rockets to maximize their return on investment in launch costs.