WASHINGTON — The U.S. Air Force is deferring planned upgrades to its most highly secure constellation of communications satellites in order to fund other Defense Department programs, documents accompanying the service’s 2013 budget request show.

According to the documents, next year’s proposed research and development budget for the Advanced Extremely High Frequency (AEHF) satellite program is $180 million less than the Air Force anticipated it would need at this time last year. Service officials intend to reallocate that funding to “higher Department priorities,” the documents say.

AEHF is not the only Air Force space program whose proposed 2013 budget is significantly lower than previously anticipated as the Pentagon faces a new era of fiscal restraint. Other examples are planned upgrades to the service’s primary space traffic management center and a budget account dedicated to devising and testing new approaches to satellite development and deployment.

When the Pentagon submits its budget request to Congress each February for the upcoming fiscal year, it typically includes five-year funding profiles for all of its programs. The AEHF funding profile included in the Air Force’s 2012 request showed a $948 million figure for 2013, with $392 million of that total dedicated to research and development. In its 2013 budget blueprint submitted Feb. 13, the service requested $786 million for AEHF, with $229 million allocated to research and development.

Like most U.S. military space programs, AEHF is funded with a combination of procurement and research and development money. As these programs move from development to production, the procurement portion of the budget increases while the research and development portion declines.

Lockheed Martin Space Systems of Sunnyvale, Calif., is under contract to build five geostationary-orbiting AEHF platforms, the first of which launched in August 2010. The Air Force expects to order the fifth and sixth satellites this year under a block-buy approach designed to save money in part by allowing the manufacturer to order components in bulk.

Previously the Air Force and Lockheed Martin had expected to use those savings to develop AEHF capability upgrades that could be incorporated on the seventh and eighth satellites, according to budget documents and industry officials. It now appears that if those savings do materialize they will be rolled into other activities.

The AEHF research and development account is split into two parts, with the upgrade effort, or Space Modernization Initiative, falling under the subdivision called Evolved AEHF Milsatcom. The Air Force is requesting $53.6 million for Evolved AEHF Milsatcom next year, some $180 million less than the service previously anticipated it would need.

According to the documents, the service added $16.5 million to the research and development account for other activities, primarily encryption technology work.

Steve Tatum, a Lockheed Martin spokesman, referred detailed AEHF budget questions to the Air Force. “The budget submission is the first step in a clear, established process that must take place before any budgetary decisions become final,” he said via email.

Christina Greer, a spokeswoman for the Air Force Space and Missile Systems Center in Los Angeles, the service’s space-hardware procurement arm, did not respond by press time to a request for comment.

Meanwhile, Air Force officials want to reallocate $45 million in 2013 funding that previously was intended for the Joint Space Operations Center (JSPOC) Mission System upgrade program to other Air Force and Defense Department priorities, budget documents show. The JSPOC is the Pentagon’s nerve center for space activities, responsible for space surveillance, orbital collision avoidance and launch support. The Air Force is requesting $55 million next year for the JSPOC Mission System upgrade, an overhaul of aging computers and other infrastructure that is expected to dramatically improve the center’s performance and responsiveness. The service anticipated it would need $100 million in 2013 for the upgrade effort when it submitted its 2012 request.

The 2012 request also said the Air Force would seek $76 million in 2013 for Operationally Responsive Space, a collection of programs and activities intended to pave the way for capabilities that can be fielded quickly in response to emerge military needs. The actual 2013 request eliminates that account entirely due to the transfer of those activities “to other space programs and reallocation of funding to higher Department priorities,” budget documents say.