WASHINGTON — With retirement of the current system of satellites that monitor space weather for the U.S. Air Force now on the horizon, the service is examining alternatives for future collection of this important data that include dedicated satellites and government sensors hosted aboard commercial spacecraft.
The Air Force for many years has relied on a suite of sensors aboard its Defense Meteorological Satellite Program (DMSP) constellation to provide notice of electromagnetic disturbances that can affect military equipment such as radios and radars on the ground. The last of the DMSP satellites currently are slated to retire around 2017.
The civil-military weather satellite constellation that will follow DMSP, the National Polar-orbiting Operational Environmental Satellite System, originally was designed to accommodate an advanced suite of space weather sensors. But soaring program costs led the program to be restructured in 2006, and the space weather requirement was eliminated in order to drive down cost and complexity.
The service for the last several months has been in discussions with industry on how best to obtain space weather data after DMSP. The service issued a request for information in April and a follow-up query Sept. 18. Responses to the latter solicitation are due Oct. 9, according to a posting on the Federal Business Opportunities Web site.
If the Air Force initiates a program based on the responses from industry, it will seek to award contracts in 2011 with the goal of having a capability on orbit by 2015 that lasts through 2020, the posting said. The government will provide the suite of sensors, which likely will be built by government labs, and the sensors could be hosted on a commercial satellite or on a small dedicated satellite, commonly referred to as a free flyer.
The decision on how to proceed will be made over the coming year based on the responses from industry and an analysis of alternatives, said Col. Stephen Pluntze, commander of the Air Force’s Defense Meteorological Satellite Group.
“We are in a position where the technology will allow us to fly these sensors on smaller satellites,” Pluntze said in an Oct. 2 interview. “We are slowly narrowing it down to perhaps a free flyer … But hosting it commercially is still an option.”
If the Air Force opts for a free flyer, smaller is better, Plunze said, to keep launch costs down and because launch slots for larger rockets are often hard to come by.
For the new program, the service hopes to go beyond the space weather monitoring capabilities provided by the polar-orbiting DMSP satellites. One example is the Air Force Research Laboratory’s experimental Communications/Navigation Outage Forecasting System (C/NOFS) demonstration satellite, which detects and measures scintillations in the ionosphere that can slow or disrupt ultra-high frequency and L-band satellite communications signals. That long-delayed satellite, launched in 2008 into a slightly inclined equatorial orbit, has been tremendously successful, Pluntze said. The service also wants an operational GPS radio occultation capability, which was successfully demonstrated in 2006 by the joint U.S.-Taiwanese Constellation Observing System for Meteorology, Ionosphere and Climate.
“They realized during the first Gulf War that peoples’ radios weren’t working all the time, and we finally figured out why,” Pluntze said. “So it took a while, but we got [C/NOFS] up and it’s turned out to be exactly what we need; it’s just not operationalized. You have to make it a little more rugged and field the correct communications systems and figure out where the data will go.”
An effective space weather monitoring capability cannot be had with a single satellite, according to an industry source who is following the program. The optimal configuration would be to have two satellites in polar orbits, similar to the DMSP configuration, plus one satellite in an equatorial orbit, the source said.
The Air Force has not decided how many space weather payloads it will procure if it moves forward with this program, Pluntze said. The service has budgeted about $15 million to start the program in 2010.
“If you can’t do it all, the equatorial orbit has a higher priority because that’s where most of the space weather effects are felt,” Pluntze said.
Meanwhile, the Air Force is preparing to launch its next DMSP satellite Oct. 6. It will then have two DMSP satellites left on the ground awaiting launches in 2012 and 2014. The final two satellites are being put through a service life extension program to increase their expected lifetimes from four to five years. The satellites are being deconstructed down to the frame and rebuilt with upgraded navigation packages and other sensors, and will be recalibrated, Pluntze said.