Reporters chasing the story of how a program to build next-generation photo-reconnaissance satellites might be restructured encountered something unexpected last week — a National Reconnaissance Office that was willing to give details. Not a lot of details and not for attribution, mind you, but few reporters could recall a time when NRO has been more forthcoming. The surprising openness of an agency that once refused to admit its own existence may be a measure of how frustrated it has grown with the Future Imagery Architecture, or it may be trying to signal that it can be responsive to Congress and the new Director of National Intelligence. Whatever the cause, don’t expect the glasnost to last for long.
While the candor continues, it is worth asking what this peek into the secret world of spy satellites tells us. National-security spacecraft (satellites) are typically divided into two categories — the “white” space systems built mainly for the military, such as satcoms and GPS, and the “black” space systems built mainly for the intelligence community. There are three types of black space systems — satellites that take pictures, satellites that eavesdrop, and satellites that relay classified information. The Future Imagery Architecture is supposed to take pictures, mainly from low-earth orbit (close enough to the earth’s surface to get a decent picture without getting sucked downward by gravity).
There’s a problem with operating in low-earth orbit. Because your spacecraft is moving at several miles per second relative to the earth’s surface, most of the time you’re over the horizon from anything interesting. If you think of the watchband on your wrist as the 24 hours in a day, and you draw two pencil lines across opposite sides of the band, those lines represent the entire time on any given day that a low-earth satellite can revisit any particular point on the earth’s surface. It’s a few minutes at most each time. You can mitigate this problem by putting more satellites in the same orbital plane, or by moving further out in space to get a wider field of view for a longer period of time. But each satellite costs hundreds of millions of dollars, and the further out into space you go, the bigger your optics have to be to get a good picture.
The Future Imagery Architecture devised in 1996 was supposed to improve photo-reconnaissance by replacing six Cold War satellites with a larger number of relatively lightweight spacecraft that could offer more frequent revisit rates. There would be electro-optical satellites similar to telescopes that could take high-resolution pictures using infrared or visible light, and radar satellites that had lower resolution but could see through clouds. The output of these “overhead” assets would be merged with that of commercial imagery satellites and airborne collectors through a ground network called MIND, providing big gains to users. MIND became operational in 2003, and works well. But the space segment of FIA has encountered repeated setbacks, and NRO now plans to shift the higher-resolution satellites to a different contractor.
The new contractor will probably adapt components from other spacecraft it has built to replace the troubled electro-optical satellites in the FIA system. Applying principles discovered by Isaac Newton, it could maintain the focal length between optical elements while shrinking the diameter of the primary mirror to save weight (a crucial launch consideration). The loss of light resulting from using a smaller mirror could then be remedied by using more sensitive detector elements in the array collecting the light for processing. The end result wouldn’t be revolutionary, but it would be good enough to avoid a dangerous gap in imagery as Cold War satellites wear out.
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