WASHINGTON — Work on two missile-warning satellite systems, one being designed as a backup to the other, is among the key drivers in the U.S. Air Force’s request for a 16 percent spending increase for space programs in 2008.

Of the Air Force’s $110 billion request for all activities, $11 billion, or about 10 percent, is allocated to space-related programs, according to a senior service official. In 2007, space represented 8.7 percent of the total Air Force budget, the official said during a Feb. 5 briefing at the Pentagon.

The Air Force is seeking to boost spending on the Space Based Infrared System (SBIRS) missile warning effort by 55 percent over 2007, a request that includes funds for a third satellite that the service has not yet decided it will buy. At the same time, the service seeks to more than triple funding for the Alternate Infrared Satellite System program, which was created as a backup or a replacement for the long-troubled SBIRS program.

The Air Force expects to decide this year whether to go through with procurement of a third SBIRS satellite or halt the program at two spacecraft and proceed with full-scale development of the alternative system. The first dedicated SBIRS satellite is slated for launch in October 2008, according to the Air Force official.

The official cited the missile warning programs as among the Air Force’s highest space priorities for 2008. The official also cited the Transformational Satellite Communications, or T-Sat, system, a new generation of spacecraft that would use laser links and Internet router technology to dramatically increase the bandwidth available to U.S. forces. However, the T-Sat budget request, at $964 million, is some $500 million less than the service anticipated requesting at this time last year, and the initial launch date has slipped from 2014 to 2016, the official said.

The official attributed the slip to congressional reductions to previous T-Sat requests and a reprogramming by the Department of Defense, and said more changes to the numbers could result this year from a pending independent cost analysis of the program.

Also in for a delay is the Space Radar, joint effort of the Air Force and National Reconnaissance Office intended to field a surveillance system that is highly responsive to both the military and intelligence community. The prime contract to build the Space Radar is slated for award in 2009, and the initial launch date has slipped from 2015 to 2016, the official said. The budget for the program, meanwhile, is now classified due to the infusion of National Reconnaissance Office funding, the official said.

One effort that receives a major boost in the Air Force’s 2008 budget request is Operationally Responsive Space, a series of projects designed to demonstrate low-cost capabilities that can be deployed quickly in response to emerging military needs. The request for the program is $87 million, which is more than double this year’s appropriation and includes funds to begin procurement of 10 small rockets to launch Operationally Responsive Space payloads.

Another priority for the Air Force is the ability to monitor the orbital environment for potential threats to its satellites, the official said. This mission has gotten increased attention in recent weeks due to China’s Jan. 11 test of a ground-based anti-satellite weapon.

The 2008 request includes a funding boost for the Space Based Space Surveillance System satellite now in development, but the amount being sought, $158 million, is less than the $194 million the service had expected to ask for one year ago. The program was restructured last year.

The service also is putting the brakes on upgrades to the Space Fence, a network of ground based radars designed to track orbital objects as they pass overhead.

Theresa Hitchens, director of the Center for Defense Information, a Washington think tank, said the delay to the Space Fence upgrade suggests there is a “disconnect” between the Air Force’s public statements on space surveillance and the funding allocated to that mission. “I don’t think they’ve been putting their money where their mouth is,” she said.

The Air Force official noted that the service also hopes to improve its space situational awareness capabilities by adding small sensors to its operational satellites that could look out for potential threats. The official said adding such sensors would be relatively simple and inexpensive, but acknowledged that the Air Force’s 2008 request includes no funding to study the concept. The official said the service plans to highlight the idea among other so-called unfunded priorities in upcoming budget discussions with Capitol Hill.

The budget request does not include funds for space-based anti-satellite capabilities despite one U.S. lawmaker’s recent assertion that China’s test points to the need for such systems. U.S. Sen. Jon Kyl (R-Ariz.), chairman of the Senate Republican Conference and ranking member of the Senate Judiciary terrorism, technology and homeland security subcommittee, called on the Pentagon to develop anti-satellite weapons during a Jan. 29 speech at the Heritage Foundation, a Washington think tank.

Kyl bemoaned the Pentagon’s reluctance to request money for space-based weapons and missile interceptors, saying it makes it difficult for supporters of such programs on Capitol Hill to provide funding for them without catching criticism for the use of earmarks.

The Air Force, however, does not want to deploy weapons in space because of the orbital debris hazard they pose, the official said.

The Air Force will ask Congress for funding to improve its ability to block enemy satellite communications with the ground-based Counter-Comm system, which was first fielded in 2004, the official said. The Air Force’s 2008 budget request seeks to increase the number of Counter-Comm systems that enable troops to jam satellites , the official said.