— New concerns about the health of the Defense Support Program (DSP) missile warning satellite constellation have prompted the U.S. Defense Department to rapidly pursue a new satellite to hedge against a potential coverage gap around 2014, Pentagon and industry sources said.

The decision comes even as the U.S. Air Force presses ahead full bore on the DSP replacement system, with plans to order up to six dedicated spacecraft that would begin launching in 2010.

The Pentagon now plans to ask Congress for permission to reprogram $117 million in 2009 to begin procurement of a Geosynchronous Earth Orbit Infrared Gap Filler System, according to an acquisition decision memorandum signed by John Young, undersecretary of defense for acquisition, technology and logistics. A copy of the memo, which was not dated, was obtained by Space News.

The military has been using DSP satellites for strategic missile warning since the 1970s, with the final satellite of the last block launching in November 2007. Lockheed Martin Space Systems of Sunnyvale, Calif., is building the new generation of missile warning satellites, the Space Based Infrared System (SBIRS), but the program has a long history of delays and technical difficulties. Lockheed Martin still is wrestling with software issues affecting the first of two dedicated geosynchronous-orbit satellites now under contract.

Lockheed Martin has delivered two SBIRS payloads that are flying on classified satellites in highly elliptical orbits and will produce two more. The first four dedicated SBIRS satellites now are planned for launch in 2010, 2011, 2014 and 2016, according to Air Force Space Command spokeswoman Jennifer Thibault. The Pentagon has decided to move forward with a fifth geosynchronous SBIRS satellite, and depending on contractor performance, may pursue a sixth before moving on to a follow-on system, a Defense Department source said.

The gap-filler decision came Oct. 23 from of a panel of top military officials, known as the Deputy’s Advisory Working Group, that was advised by an infrared joint analysis team led by Air Force Gen. Kevin Chilton, commander of U.S. Strategic Command, the memo said. Chilton’s joint analysis team meeting was spurred by an event in the past couple of months that caused degradation in DSP coverage, heightening the risk of a coverage gap in the future, Pentagon and industry sources said.

The sources declined to be specific about the nature of the degradation; the number of DSP satellites, their health and their orbital disposition is classified, and as such the Air Force will not comment on them, Thibault said. Typically four satellites in geosynchronous orbit are required for full global coverage.

A previous joint analysis team meeting had determined that any potential risk of a coverage gap could be mitigated by changing the way the SBIRS elliptical-orbit payloads are utilized. At the recent meeting, there still were dissenting views on the need for a gap-filler satellite, the Defense Department source said.

But Young’s acquisition decision memorandum said the gap-filler satellite is required to “help provide continuous strategic missile warning coverage,” and would launch in 2014. It will be a low-risk solution that uses existing technologies, hardware and ground systems, and must provide three years of service at a capability level at least equal to that of the DSP satellites, the memo said.

The memo directs the Air Force to consider a standalone satellite or an infrared sensor hosted aboard another government or commercial satellite. The service also is directed to provide an acquisition strategy and source selection plan to Young by Dec. 19.

The Pentagon will hold a firm, fixed-price competition to build the sensor and satellite with commercial vendors as well as government-owned contractor-managed facilities such as the U.S. Department of Energy’s Sandia National Laboratory in
, the Defense Department source said. The Pentagon last year commissioned a $4 million study led by Sandia of a missile warning gap-filler satellite option after the latest software problems on SBIRS surfaced.

Among the several possibilities under consideration at this point is a sensor similar to the first elliptical-orbit SBIRS sensor built by Northrop Grumman Electronic Systems of Linthicum, Md., sources said. Unlike the Northrop Grumman-built sensors for the geosynchronous SBIRS satellites, the elliptical-orbit sensor pivots on three axes and could be fitted to many types of geosynchronous platforms, sources said.

Also under consideration is an experimental sensor built by Raytheon Space and Airborne Systems of El Segundo, Calif., under an effort hatched in 2006, after the Pentagon restructured the SBIRS procurement, reducing the planned purchase of geosynchronous satellites to no more than three and possibly only two. The Pentagon since has reversed course on SBIRS, despite the program’s continued troubles.

A second experimental missile warning sensor, built by SAIC of
San Diego
in parallel to the Raytheon sensor and now designated for launch aboard a commercial host satellite, is not considered an option for the gap-filler, according to sources.

Yet another possibility, according to one industry source, is to plug any potential gap with an additional satellite in highly elliptical orbit. This source said Congress, which allocated $2.1 billion for SBIRS in 2009, might give a chilly reception to any solution that looks like a competitor to SBIRS. Congress in 2007 declined to fund Air Force plans to launch a SBIRS-alternative demonstration satellite in 2010.

The Pentagon still is formulating its latest plan and has not yet brought it to Congress for approval, the Defense Department official said. It is expected to cost between $350 million and $800 million, with the funds coming from six other Pentagon accounts, including the Operationally Responsive Space office, the source said.

The decision to pursue a new capability likely comes out of a desire to mitigate the dual risks posed by an aging DSP constellation and an unproven and long-delayed SBIRS constellation, said Loren Thompson, chief operating officer at the Lexington Institute in Arlington, Va.

Several sources familiar with the DSP constellation stressed the
United States
does not currently have a gap in missile warning coverage nor is one imminent.