The U.S. Air Force will pay United Launch Alliance (ULA) an extra $15 million to make room for another mission on an already-crowded 2009 launch manifest as the company tries to clear a backlog that has built up due to technical issues that grounded its fleet for much of last year.

At the request of the Air Force and NASA, Denver-based ULA, builder and operator of the Atlas and rockets that launch the vast majority of U.S. government payloads, will increase its operating tempo for Atlas 5, the workhorse of the fleet with 34 missions scheduled through early 2012. ULA now plans to launch seven Atlas 5s this year.

“The acceleration adds flexibility to the schedule and supports at least one additional slot in 2009,” the Air Force Space and Missile Systems Center’s Launch and Range Systems Wing, Los Angeles, said in a written statement. The acceleration applies only to Atlas 5, said the statement, which cited “delays in spacecraft availability” as a factor in the current logjam.

ULA was established in 2006 as a joint venture between Boeing Co. of Chicago and Bethesda, Md.-based Lockheed Martin Corp. The company’s main offering is the Atlas 5 and Delta 4 rockets, developed separately by Lockheed and Boeing, respectively, under the Air Force’s Evolved Expendable Launch Vehicle Program. ULA also operates the smaller, Boeing-designed Delta 2 rocket.

The Air Force will pay for additional ULA personnel working more shifts at Cape Canaveral Air Force Station in Florida and at Vandenberg Air Force Station in order to shorten the turn-around time between Atlas 5 launches. The goal is to reduce that period from 60 to 45 days for non-nuclear-powered payloads and from 90 to 75 days for payloads that require extra time to install nuclear-powered batteries on site.

Atlas 5 rockets launched twice in 2008 – once on behalf of the U.S. government – largely because certain vehicle components were not adequately tested and had to be run through testing again. Another problem related to the gimbal actuator system on the rocket’s Russian-built RD-180 main engine. All of those issues have been resolved, ULA spokeswoman Julie Andrews has said.

Accelerating Atlas 5’s ground operations tempo will open up a slot for the July launch of the Defense Department’s DMSP-18, a polar-orbiting weather satellite replacement in the Defense Meteorological Satellite Program constellation. The Air Force delayed the DMSP-18 last fall, shortly after ULA announced the testing problems.

The Air Force has not decided whether to pay for the additional personnel ULA would require to continue with the accelerated schedule in the coming years.

“We are assessing whether the Air Force will continue this acceleration beyond [fiscal year 2009],” said the Air Force statement, provided by Tonya Racasner, spokeswoman for Space and Missile Systems Center.

If funding for the extra personnel is provided beyond this year, ULA could schedule eight Atlas 5 launches per year instead of an average of about six per year, said Bill Wrobel, NASA assistant associate administrator for launch services.

“It’s about two slots per year. It’s not a lot, but it’s better than what we have now,” Wrobel said.

NASA has just one Atlas 5 launch scheduled this year – the April launch of the Lunar Reconnaissance Orbiter – but would see a real payoff in 2011 if the manifest opens up enough to resolve a potential conflict between the roughly $1 billion Juno mission to Jupiter and the $1.9 billion, nuclear-powered Mars Science Laboratory (MSL).

Both are slated to launch from the same pad atop Atlas 5 rockets, and both have narrow launch windows, which must be timed for when the planets they will explore are in favorable alignment with Earth.

MSL was originally scheduled for launch in October 2009, but NASA officials announced in December that they had given up trying to finish the complex spacecraft in time. Forfeiting the 2009 window meant waiting for the next favorable alignment of Mars and Earth, which will occur in October 2011.

But finding an October 2011 launch slot for MSL is problematic because Juno has a 20-day launch window in August. Given the 90 days currently required to prepare for the launch of a nuclear-powered payload, it would be impossible to launch MSL during its October window. If that preparation time can be condensed to 75 days, MSL could make its window provided Juno launches at the beginning of its window.

Another alternative for MSL is to launch in December using a different launch trajectory.

Compounding the range conflict are three non-NASA missions scheduled to launch in the fall of 2011. With an accelerated Atlas 5 launch tempo, those missions could be launched before Juno and MSL, Jim Green, director of NASA’s planetary science division, said during a Jan. 9 meeting of the NASA Advisory Council’s planetary science subcommittee.

While NASA expects to have its new plan and cost estimates for MSL ready by late February or early March, the space agency is anxious just to get the rover mission on the Atlas 5 manifest. The space agency sees the Air Force decision to step up the ground processing tempo as an important step.

“We have a couple things we’re trying to squeeze in, and 2011 is where it starts to pay dividends,” Wrobel said. “For us, in 2011 it gives us a home for MSL.”