Missile warning satellites, which in the past have required the largest rockets in the Pentagon’s arsenal to reach orbit, could
be launched in the future aboard some of the smallest, according to a senior industry official.


The Defense Support Program satellites, which provide missile warning coverage today, were launched aboard Titan 4 rockets, and in the case of the last spacecraft in the constellation, a heavy-lift Delta 4. When t
heir planned replacements, the Space Based Infrared System (SBIRS) High satellites, begin launching in 2009 they will use
medium-lift Evolved Expendable Launch Vehicles.


The trend towards using increasingly smaller rockets may continue with the satellites that eventually follow SBIRS High, according to Brian Arnold, vice president for space systems at Raytheon Space and Airborne Systems in El Segundo, Calif.


Arnold, a retired U.S. Air Force three
star general who last served as commander of the Space and Missile Systems Center, where he oversaw the service’s work on a variety of space programs including launch vehicles and missile warning satellites, said that an experimental missile warning payload that the company recently delivered to the Air Force could be launched on a small rocket like an Orbital Sciences Minotaur-1 or Space Exploration Technologies Falcon-1.


The payload, which was developed as part of the Alternative Infrared Satellite System (AIRSS) risk reduction effort, is intended for ground demonstration at the Air Force Research Laboratory, but could be mated with a satellite platform for launch as part of a program like the TacSat satellite series – if the military elects to use it in space, Arnold said in a March 28 interview. The payload also would require a system for processing data in space or on the ground before it could be used in a space demonstration, Arnold said.


Based on the work with the AIRSS payload thus far, an operational version of the sensor
likely could fit on a small satellite as well, potentially yielding significant savings on launch costs for the military, Arnold said.


Raytheon developed the payload under a $54 million contract awarded in September 2006; SAIC Corp. of San Diego won a similar AIRSS payload contract that same month worth $24 million. SAIC also recently delivered its payload to the Air Force.


Arnold said
the company has discussed the possibility of launching its AIRSS payload with senior Air Force and Missile Defense Agency leadership. While those officials indicated interest in using the payload, there has been no funding commitment for a flight,
he said. Other possibilities, which
also are not funded at this point, include incorporating the AIRSS payload into a SBIRS High spacecraft around the middle of the next decade, he said.


The Air Force took what may have been a step in the direction of getting at least one of the payloads ready for launch
March 31 with the award of a $31.2 million contract to SAIC to upgrade the sensors in the AIRSS
payload. SAIC’s job will be to put the sensors in a configuration that could be reviewed to determine if it is qualified for use in space. That effort might
also reduce the risk associated with building space qualified parts in the future, according to a Pentagon contract announcement.


Joe Davidson, a spokesman for the Space and Missile Systems Center, said in a written response to questions April 3 that SAIC’s contract is intended to upgrade the company’s sensor to a “full payload.” While Davidson said that there are no plans for an additional similar contract for Raytheon, Arnold had noted during the interview that Raytheon’s payload was built from parts that could be space qualified upon Air Force review.

The AIRSS effort was initiated as a possible alternative to the SBIRS High program as part of a restructuring that occurred on
in late 2005. While AIRSS was conceived as a potential replacement for the SBIRS satellites after the second satellite in the SBIRS constellation, the Air Force now views the program as a follow-on to SBIRS, and has renamed it accordingly as the Third Generation Infrared Surveillance system.


The SBIRS High satellites feature infrared sensors that are designed to scan the Earth looking for missile launches or other heat-causing events, as well as a sensor that can stare at particular areas of interest for long periods of time. The AIRSS payloads are intended to demonstrate the concept of a sensor that could stare continuously at the entire visible portion of the Earth.


In addition to keeping better tabs on heat-producing events, taking the scanning sensor from the mix also simplifies the design of the payload and boosts its reliability by reducing the need for moving parts, Arnold said.


Melissa Koskovich, a spokeswoman for SAIC, said in a written response to questions on March 29 that the large focal plane arrays used with the AIRSS payload to enable continuous staring at the entire visible portion of the Earth are still “leading edge technology” and that there is “great value” to extensive ground testing with the hardware. However, she said that the payload would be “flight worthy” at the end of the Air Force Research Laboratory’s testing and qualification work, and that the company is ready to support the Air Force with whatever it chooses to do.

Comments: jsinger@space.com