January 22, 2008Satellites represent an extremely impressive technological achievement, serving as communications relays in orbits as high as 22,600 miles above the Earth or providing precise location information to handheld Global Positioning System receivers priced at as little as $100.
At the same time, satellite development and manufacturing seems stuck in the pre-automation age, with each bird laboriously handcrafted in a process that takes years and with costs for new Defense Department satellite systems routinely measured in the billions of dollars.
The Transformational Communications Satellite (TSAT) system for example, intended to serve as the next-generation space-based communications hub for Defense and capable of transmitting huge amounts of data in seconds rather than minutes using current systems, won't go into service until 2016 and has a price tag of $16 billion.
The hefty cost for TSAT can be attributed, in part, to capabilities not found in previous military satellite systems, including on-board signal processing, enhanced encryption and laser cross links between satellites, which will make it easier to transmit information to users anywhere in the world.
Adding such capabilities boosts costs and increases development time, said Gary Payton, Air Force undersecretary for space. Payton is looking for better, cheaper and faster ways to develop and deploy satellites through the Operationally Responsive Space Office established by Defense last May in response to a congressional mandate in the 2007 Defense authorization bill.
ORS, headquartered at Kirtland Air Force Base in Albuquerque, N.M., will capitalize on efforts by the Air Force Research Laboratory, also headquartered at Kirtland, to develop small, affordable satellites under its Tactical Satellite program, Payton said.
The ultimate goal, he said, is to develop satellites with plug-and-play components that hook together in the same manner that anyone with a computer adds drives or printers via a Universal Serial Bus interface.
To slow spiraling costs, ORS also needs to focus on development of simple, single-mission satellites. The only way the project will succeed is if developers respond with an unwavering "no" when asked to add one more function to a satellite, Payton said.
In December 2006, TacSat-2 was launched into orbit carrying a payload focused on signals collection. Kirtland plans to launch TacSat-3 this June, with a payload focused on collecting images using a hyperspectral sensor, Payton said. (TacSat-1, a micro-satellite developed by the Naval Research Lab to transmit data over the Defense secret intranet, is waiting for a launch vehicle, Payton said.)
The cost to develop and launch the TacSat-3 is $75 million. That's relatively low compared to systems such as TSAT, said Thom Davis, the program manager for TacSat-3, but its hyperspectral technology represents an advance in space-based imaging, making the cost that much more a bargain. The sensor, developed by AFRL in conjunction with the Army Space and Missile Defense Command, slices light spectrum into various wavelengths, which allows it, for example, to peer through a jungle canopy and identify various objects, such as a tank, Davis said.
TacSat-3 carries an onboard computer to process image information. It downloads the images to a ground station hooked up to a laptop computer, which imagery analysts can use. TacSat-3 is designed to be operationally responsive to field commanders, who can use a simple backpack military radio, such as the AN/PRC-117, to communicate with the satellite in the ultrahigh frequency band, according to Davis.
TacSat-3 runs on a modular bus that is the forerunner of the plug-and-play satellite system and also carries an experimental plug-and-play payload, he said.
AFRL and ORS are working to develop next-generation TacSats based on full plug-and-play architecture, said Dr. Jim Lyke, technical adviser for the space electronics branch, space vehicles directorate at AFRL. Lyke, described as the "father of plug-and-play satellites" by Michael Kleiman, public affairs officer at Kirtland, said the satellite architecture will be developed around standards such as the PC industry's USB and the SpaceWire high-speed link and network standard originally developed by the European Space Agency.
These standards invoke what Lyke described as a "set of discovery principles" that find and join various components in a satellite based on descriptions of the components contained in an Extensible Markup Language (XML) transducer data sheet maintained in a data registry. These standards allow a spacecraft bus to discover new components much in the same manner as when a computer user plugs a new printer into a PC through a USB port, Lyke said. The space component is configured automatically to work with the bus and all other components in the spacecraft.
Maurice Martin, program manager at AFRL, said the plug-and-play approach makes it easier to add capabilities to a satellite, such as laser cross links. Once a data sheet is developed for the links, they can be plugged into the satellite, instead of using costly, manual hard wiring. Martin said the lab has developed a mock-up of such a satellite, though no launch date has been set.
Lyke said AFRL and ORS should be "technologically close" to development of a true plug-and-play satellite by 2015 and "if we push, we could get it all worked out by 2015."
January 22, 2008