UPDATE July 23: Rising tensions between the U.S. and Russia can only help SpaceX's efforts to open bidding on Pentagon missions.

Editor's Note: The article was changed to point out that Boeing's Delta IV rocket uses the RS-68 engine manufactured by Aerojet Rocketdyne of Rancho Cordova, California. The RD-180 engine is used by Lockheed's Atlas V launch vehicle.

Original story begins here:

Citing “anomalies” in Space Exploration Technologies Corp.'s (SpaceX) flights, the U.S. Air Force has yet to certify the company for Pentagon contracts.

In a letter to Rep. Mike Rogers (R-Ala.) a member of the House Armed Services Committee, the Air Force said there were problems in three of SpaceX’s missions: reignition failure in a second-stage rocket engine in September 2013, an engine fire during the December 2013 mission, and “unacceptable fuel reserves” at one point in the January mission, states the letter dated May 20 and cited in a report Monday from Bloomberg.

The Air Force also said it was in talks to address “lesser but still significant flight and ground operations,” but also said the space cargo transport company founded by billionaire inventor Elon Musk has made the most progress among other private firms vying for defense contracts.

In addition to its work with NASA and companies launching commercial and research satellites into orbit, SpaceX is seeking contracts worth billions of dollars to boost secretive Pentagon satellite missions into orbit.

SpaceX wouldn’t comment on its efforts, but NASA released the following statement to International Business Times Monday:

NASA has successfully returned space station resupply launches to U.S. soil, ending our reliance on other countries to get to space and bringing the associated jobs back to America. Our private sector partners in this effort are meeting their obligations under their Commercial Resupply Services contracts. The contracts and certification process allow us to work with Orbital Sciences and SpaceX to ensure that flights are as safe and reliable as possible. To date, NASA’s partners have delivered about 14,000 pounds of vital supplies to the International Space Station, including science and research experiments, supplies, and hardware for the orbiting laboratory.

Currently only Lockheed Martin Corp. (NYSE:LMT) and the Boeing Co. (NYSE:BA) have clearance to perform Pentagon missions through their United Launch Alliance joint venture. SpaceX designs and manufactures its rockets in the United States. Lockheed's Atlas-5 rocket uses the RD-180 engine while the Boeing Delta IV rocket uses the RS-68 engine manufactured by Aerojet Rocketdyne of Rancho Cordova, California.