Small satellites and light payloads for earth observation were the topic for a keynote presentation I attended yesterday given by Dr. Pete Worden, director, NASA's Ames Research Center at Moffett Field in the Bay Area. Worden was speaking at the Space and Missile Defense Conference in Huntsville, Alabama. In his presentation, he discussed the tenuous situation in which the United States finds itself to launch satellites to monitor and assess environmental and climate conditions in order to replace an aging fleet. Citing the decadal survey (complete report in PDF) by the National Academies that concluded that our current constellation of environmental satellites is "at risk of collapse," Worden recommended a program for small satellite development called Venture Class. "If we don’t go in this direction, our competitors will," said Worden.
According to a NASA press release from June 12th, "The Earth Venture missions are part of NASA's Earth System Science Pathfinder program. The small, targeted science investigations complement NASA's larger research missions." One of the objectives of Venture class satellites is to launch a constellation of satellites on a single launch vehicle. These "small sats" weigh approximately 150kg or about 330 lbs. By contrast, Landsat 7 weighs 5000 lbs. or about 2270kg.
An example of some of the small satellites for earth observation are being constructed by Surrey Satellite Technologies, Ltd. in the UK that have sub-meter accuracy for panchromatic imagery and weigh approximately 350Kg.
Another innovation discussed by Worden were "cubesats." Think milk carton-sized instruments with cell phone-like electronics that can be stacked together. And what about ground stations for data recovery? Think "Dish Network" antennas that fit in your backyard.
Worden see that it's possible to get away from long lead time for satellite development and focus on using smaller launch vehicles." Commenting on cubesats and other lightweight instruments, Worden says, "It changes space from a launch and develop problem to an application problem; [with] multiple sensors – it’s a revolution that is coming (in 5-10 years) the limitations is the ability to get these things into space."