By Andrea Shalal
WASHINGTON (Reuters) - U.S. Defense Secretary Ash Carter and the nation's spy chief this week urged a key Senate committee to amend federal law to allow a joint venture of the two largest U.S. arms makers to use more Russian RD-180 rocket engines.
Carter and Director of National Intelligence James Clapper urged Senate Armed Services Committee Chairman John McCain, in a letter dated May 11, to change the law so the Pentagon can retain "assured access to space". This is a legal requirement that mandates availability of two satellite launch vehicles so the U.S. military can always get satellites into space, even if one of the rockets is grounded due to a catastrophic failure.
The letter, obtained by Reuters, is the latest twist a drama surrounding United Launch Alliance, a joint venture of Lockheed Martin Corp <LMT.N> and Boeing Co <BA.N>, and its sole potential competitor Space Exploration Technologies, or SpaceX. The latter is nearing certification by the Air Force to compete for some military and spy satellite launches.
The current dispute centers on a clause in the 2015 defense authorization law banning use of Russian engines that were not paid for before Russia's annexation of Crimea last year.
The Air Force - and now Pentagon leaders - have asked Congress to change the law to include engines that ULA ordered, but had not paid for, at that time for use in its Atlas 5 launch vehicle.
ULA is seeking the relief because it is discontinuing use of most of its U.S.-powered Delta 4 rockets because they are too costly, and its new Vulcan rocket won't be ready until 2022 or 2023.
The House Armed Services Committee has already proposed a similar change.
Air Force Secretary Deborah James last month said changing the law would allow ULA to compete for 18 of 34 competitive launches between 2015 and 2022 against SpaceX, versus just five launches.
No immediate reaction was available from McCain, but he has been critical of continued use of the Russian rocket engines, citing concerns about the cost and reports Russia is inflating its prices.
Carter and Clapper did not address that issue. They said even if the Air Force certifies SpaceX, losing access to the Atlas 5 and Delta 4 rockets could leave the Air Force with "a multi-year gap where we have neither assured access to space nor an environment where price-based competition is possible."
ULA says the proposed change would preserve meaningful competition and avert a potential gap in capability.
SpaceX executives argue ULA should have focused long ago on lowering the cost of its Delta 4 rockets.
(Reporting by Andrea Shalal; Editing by Chizu Nomiyama)