he U.S. Department of Energy’s Sandia National Laboratory is exploring the feasibility of building and launching a missile warning satellite relatively quickly to plug any gaps in coverage that could open up in the coming years, according to Pentagon and industry officials.

The $4 million Argus study was commissioned by the Office of the U.S. Secretary of Defense Feb. 6, long before news of the latest delay on the Space Based Infrared System (SBIRS) missile warning program surfaced. Some industry officials said the SBIRS delay increases the likelihood of the study evolving into a full-blown program.

So far, however, the ongoing Argus study has not been affected, according to Cheryl Irwin, a spokeswoman for the Office of the Secretary of Defense. In a written response to questions, she said the study was commissioned to explore a “possible contingency option should that become necessary.”

According to a Pentagon source, the study originally was ordered as a hedge against further SBIRS delays or the possibility that the last of the Defense Support Program missile-warning satellites does not safely reach orbit later this year. That satellite is slated to launch atop United Launch Alliance‘s Delta 4 Heavy rocket, which failed to place its dummy payload into a sustainable orbit in its only launch to date.

SBIRS, the designated replacement for the Defense Support Program, has a long history of delays and cost growth. Until recently, the first of at least three planned SBIRS satellites was scheduled to launch in early 2009. However, Air Force Secretary Michael Wynne has warned that an additional six- to 12-month delay now is likely due to computer-related issues and on-orbit problems with an unspecified satellite that has similar design features.

“The problem is a safe hold that did not work on a current satellite, causing mission termination; and the design similarity to the [geosynchronous]

satellites, which caused a no fly condition,” Wynne said in a Sept. 26 memo to John Young, acting undersecretary of defense for acquisition, logistics and technology. “Compounding the issue is the fragility of the computer architecture, specifically the timing loop.”

Wynne said SBIRS prime contractor, Lockheed Martin Space

Systems of Sunnyvale, Calif., is working on fixes to both problems. “The investigation and engineering research plan should be available by late October,” Wynne wrote in the memo, a copy of which was obtained by Space News.

Wynne asked that a key program review slated for Oct. 9 be delayed by about a month.

The SBIRS program originally was to include four dedicated satellites in geosynchronous orbit, plus one spare, and two infrared sensors hosted by classified satellites in highly elliptical orbits. But the program was restructured in late 2005 after its cost soared from just over $2 billion to more than $10 billion. The restructuring reduced the number of geosynchronous satellites to no more than three, and possibly only two, and in the meantime the Pentagon initiated work on a replacement dubbed the Alternative Infrared Satellite System (AIRSS).

Earlier this year, Pentagon officials, buoyed by what they saw as recent progress on SBIRS, elected to procure the third satellite, with an option to buy a fourth. The Air Force also ordered an additional two sensors to be hosted aboard satellites in elliptical orbit.

The latest problem is limited to the geosynchronous SBIRS satellites, Wynne wrote. The first of the elliptical-orbit SBIRS sensors is in orbit and operating well, and the second is awaiting launch, he wrote.

Wynne’s memo said another $1 billion in SBIRS cost growth is possible due to the latest troubles.

In a written statement, Lockheed Martin spokesman Stephen Tatum said, “We are aware of Secretary Wynne’s concerns with cost and schedule, and while our estimates are not of that magnitude, we are collaborating with our customer to reach a common understanding and timely resolution of the issues.”

Tatum said development of the first two SBIRS satellites “

is proceeding and we are confident in our path forward to successfully execute this vital national security program and sustain the on-orbit missile surveillance satellite constellation.”

Asked to identify the satellite whose failure prompted concern about SBIRS, Tatum declined, citing classification restrictions.

The Argus study, meanwhile, is focusing on technologies already developed by Sandia, which is located near Albuquerque, N.M., Irwin said. Sandia specializes in building nuclear weapons, but also has experience with satellites and sensors. The Johns Hopkins University’s Applied Physics Laboratory of Laurel, Md., which has a long history of building satellites for the U.S. government, is participating in the study as a team member, Irwin said.

“The study is still in progress including consideration of various options that would impact projected cost,” Irwin said. Industry officials familiar with the Argus study said a gapfiller satellite could cost anywhere between $500 million and $1 billion.

Wynne’s memo said the fourth geosynchronous SBIRS satellite may now be at risk. He said the AIRSS system might be available to replace that satellite, “but this depends on technology development.”

In a written response to questions, Lt. Shirali Patel, a spokeswoman for the AIRSS program office, said the effort is focused on developing prototype missile warning sensors. She said that depending on funding, the program could produce a satellite to replace the fourth SBIRS satellite, but conceded that this would pose software compatibility challenges. Patel also said that AIRSS now is viewed as a follow on rather than a stopgap replacement for SBIRS and that its name has been changed to the Third Generation Infrared Surveillance system to reflect that.

Irwin noted that the Argus study is exploring a satellite that could be integrated with “our existing missile warning system.” The study is not considering Argus for possible integration with future missile warning systems, she said.

Meanwhile, the Pentagon source, who declined to be identified, downplayed the connection between the classified satellite that failed on orbit and the SBIRS problems. This source said there have been concerns with SBIRS software that date back to January, when the first spacecraft was tested in a thermal vacuum chamber.

The source also said Wynne may have been seeking to err on the conservative side in estimating that the cost of making the first SBIRS satellite flight-worthy could be $1 billion. Lockheed Martin has estimated the cost to be $250 million, while the Pentagon’s independent Cost Analysis Improvement Group came up with a $500 million figure, the source said.

Regarding the possibility of a gap in missile warning, the Pentagon official said there are ways to configure even a depleted constellation to maximize coverage or areas where missile launches are deemed most likely.

Tatum, in his written statement, said Lockheed Martin still hopes to have the first SBIRS satellite available to launch in 2009.

Stephanie Holinka, a spokeswoman for Sandia, deferred to the Pentagon for comment.