WASHINGTON — A new U.S. government space transportation policy throws its weight firmly behind the two rocket families that were developed under the Air Force’s Evolved Expendable Launch Vehicle (EELV) program.

The U.S. Space Transportation Policy, signed by President George W. Bush in December and released Jan. 6, directs the Defense Department to keep Boeing Co.’s Delta 4 and International Launch Services‘ Atlas 5 in business for the foreseeable future.

The Air Force in the late 1990s helped fund the development of the two EELV families with the expectation that a growing commercial market would subsidize their operations. That market failed to materialize, leaving the Air Force to pick up more of the cost of supporting the vehicles. The new policy codifies that arrangement, while leaving the door open for future competition if someone were to develop a suitable vehicle.

“This is not a subsidy to either provider of EELV, but the EELV providers should not lose money when they do business with the U.S. government,” the official said. “We wanted to make sure we were providing a stable signal as to our intention while at the same time making it clear if another provider proves they can do it, have at it.”

Brett Lambert, vice president for corporate service at DFI International, a consulting firm here, said the policy is an honest assessment of the current launch vehicle situation and a recognition by the White House that there are not a lot of choices.

“With EELV, we are where we are,” Lambert said. “There are not a lot of options that are realistic. This is just acknowledgement of the de facto situation and the realization that there is not much we can do about it even if we wanted to change it.”

The Pentagon must pay the annual fixed costs for both EELV rocket makers, but calls for the United States to revisit the funding arrangement by 2010 and determine if any changes are warranted. The Department of Defense and the U.S. Air Force will determine what those annual fixed costs are, but may very well face some hard budget choices to fulfill the policy, the official said.

“It makes very clear that this policy does not come without a price tag, and people need to get on board,” Lambert said. “The price tag won’t be much as if they were to start from scratch, but we have a bill we need to pay and it’s going to be the policy of the U.S. government to pay the bill.”

Air Force spokeswoman Maj. Karen Finn did not reply to a phone call seeking comment.

The policy also directs NASA and the Department of Defense to collaborate on the development of future launch requirements and to make a joint recommendation to the president regarding the heavy lift options for future exploration needs.

“These options will emphasize the potential for using derivatives of the [EELV] vehicles to meet space exploration requirements. In addition, the [NASA] Administrator shall evaluate the comparative costs and benefits of a new dedicated heavy-lift launch vehicle or options based on shuttle-derived systems,” the policy states.

“With the previous policy, there was a sharp division between what NASA and the U.S. Department of Defense were responsible for,” a senior administration official said in a Jan. 6 briefing. “We tried to break that barrier down, along with stabilizing the government’s position in regard to the Evolved Expendable Launch Vehicle.”

The door remains open for other heavy lift options, primarily either a space shuttle-derived vehicle or an entirely new approach, but “the language is not intended to encourage development of a brand new booster,” the senior administration official said.

Michael Kahn, vice president of space programs for Minneapolis-based ATK, which manufactures the space shuttle solid rocket boosters, said the company does not read the policy as favoring EELV-derived vehicles. “It states that new launch vehicles be considered for space transportation that use shuttle-derived flight-proven propulsion systems to compete on level playing field,” he said.

Under the policy, the U.S. government also recognizes for the first time the development of a commercial market for carrying passengers to space, spurred by the Ansari X Prize competition that was won in 2004. “It’s too early to know how this will go, but the administration is strongly supportive of the industry and this policy and takes account of them,” the official said.

The policy continues to require that U.S. government payloads, such as satellites built by the Pentagon or NASA, be launched on U.S.-made rockets unless exempted by the White House. As with the previous U.S. space policy, the prohibition on non-U.S. launches does not apply when another nation offers to provide a launch as part of an international scientific program or some other cooperative government-to-government program.

The policy also reiterates Bush’s January 2004 call for the space shuttle to return to flight “as soon as practical” to complete assembly of the international space station by around 2010, after which time the fleet would be retired. It also restates the president’s call for the development of a new crew exploration vehicle for missions beyond low Earth orbit.

This was the fourth set of guidelines issued by the White House since President Bush ordered a review of the nation’s space policy in May 2002. Previous policies have covered remote sensing, satellite navigation and space exploration.