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SPACE TECHNOLOGY
July 2007
Can the Air Force Build a Satellite in Six Days?
By Grace Jean
 KIRTLAND AIR FORCE BASE, N.M. — Building a small satellite in the future could be as simple as ordering a personal computer today.
At least, that’s what Air Force Research Laboratory’s scientists are trying to achieve. They are experimenting with a “plug -and-play” concept that will allow engineers and technicians to construct a spacecraft in as little as six days.
“Just as you plug a mouse or keyboard into your computer, your computer pauses to recognize that it was added and figures out how to integrate it into the system ... That’s what we’d like to do on a bigger scale with aerospace platforms,” says Jim Lyke, principal electronics engineer and technical advisor for the lab’s space electronics branch.
Space technologies, such as satellites, traditionally have taken years, if not decades, to develop.
But with the nation becoming increasingly dependent upon space-based systems, and with a growing need to protect and reconstitute those technologies following hostile or naturally occurring events, the ability to piece together satellites faster and send them into orbit quickly is an urgent imperative. So pressing is the movement that it has a name: operationally responsive space.
To build on-demand satellites for that purpose, researchers have turned in part to the commercial electronics industry for inspiration. There, the plug and play concept — in which components manufactured by different companies are compatible and can integrate autonomously into a single operating system — has been around for more than a decade.
With the method so ubiquitous in the PC industry, it seems an easy principle to apply to space technologies. Not so, says Lyke.
“In the spacecraft world nothing is plug and play. We’re the first activity to create a true plug and play,” he says.
Spacecraft manufacturers do not follow universal standards, says Lyke. Adding to the difficulties is that many of the technologies are custom-designed and are often from different vintages.
“A lot of people believe they can have plug and play by standardizing. It’s an easy seductive idea: ‘Here, use standard B because everyone is building standard B.’ The problem is, these standards don’t go far enough,” says Lyke.
For example, two gyroscopes manufactured by different companies may both comply with an electronics guideline known as RS-422. But chances are the devices still won’t interoperate in a spacecraft because each vendor builds them differently.
“Even though they comply with the standard, there is no understanding as to how those components were supposed to work,” he says.
Plug and play involves specifications not only on a physical level but also on a semantic level. Electronic devices may look the same, but they may not “speak” the same language. Attempts to standardize equipment in the past failed because people didn’t go this extra length, he adds.
Having uniformity in space components will allow the industry to generate a catalog of compatible parts that engineers can turn to when constructing a satellite. Today, that registry does not exist.
“We think even if we can get 30 to 50 items in that catalog, we can begin to do [plug and play],” says Lyke. “What we’re trying to do is provide a system, from the individual components down to the bolts, so that we can build a greater variety of spacecraft, more than we could ever put in a hangar.”
Researchers envision that one day technicians will be able to use a software tool to help build a small satellite for a specific purpose.
They will input the mission specifications on a computer, and the software will generate a menu of components they need to build the satellite. The technicians then simply pull those parts off a shelf in a warehouse and begin piecing them together.
“In some sense, our research is a battle against the nature of complexity,” says Lyke. “We believe, in the long run, that all systems will be built on these principles — that complex things will be made to look simple.”
Even on a satellite, he says, the panels will have communication capabilities so that they can self-organize and interact, much as a thumb drive does when it’s plugged into a computer.
To prove that the plug-and-play concept will work for space systems, researchers are building a satellite from scratch. It is “a modular satellite with open standards and interfaces,” Lyke wrote in a paper that was presented at a conference earlier this year. The spacecraft will have pegboard-like grid structures that allow 25 components to be mounted, including three reaction wheels, a magnetometer, two batteries, a GPS radio and a tactical radio.
At about 73 pounds, the plug and play satellite will be smaller than the TacSat series of 800-pound experimental satellites. Designed to fit on an adapter called the ESPA ring that sits between a rocket and its primary spacecraft payload, the satellite will be able to accommodate multiple payloads, including surveillance and optical sensors, communications equipment and radar.
The team currently is building the panels, writing the software and developing some of the components. The satellite will undergo a critical design review this fall.
“We are looking at the possibility of flying it as early as 2009,” Lyke says.
In an industry where many have spent entire careers building a single spacecraft, there are skeptics who believe the plug-and-play concept is unfeasible. Condensing a process that has typically taken years into only a matter of days is radical in any field, but especially so in space.
“It’s a classic dilemma of technology developers who are always fighting the perceived risk of technology versus the needs of the mission,” says Lyke.
“We believe it won’t be until you build an entire satellite using plug-and-play principles that you’ll see the benefit,” he says.
In the beginning, scientists will not be able to build a spacecraft that performs on par with a $1 billion satellite, he says. Instead, they will build a system that is capable of carrying out tactical, short duration missions.
“We’re not trying to take on all space. We’re trying to do a number of simple, useful missions,” says Lyke.
Believers view this new approach as the wave of the future.
“It’s an entirely different way of building satellites, and technology today enables that kind of architecture, so we want to exploit that and see if there are ways to change the business model in a dramatic way,” says Peter Wegner, the laboratory’s responsive space lead.
Some in industry are beginning to take to the concept.
Raytheon Corp. built a surveillance sensor payload in 15 months for TacSat-3 using commercial technologies.
“Most of the payloads we developed in the past were customized. This one we tried to make inexpensive by using existing technologies and standards,” says Tom Hastings, director of engineering at Raytheon’s space and airborne systems division.
The Air Force Research Laboratory developed an experimental avionics payload for the satellite, with four simple sensors and instruments, as a demonstration of the concept, says Lyke.
“By flying the technology, we do reduce the barriers of acceptance by showing we have enough maturity in the technology to reach flight,” says Lyke.
TacSat-3 is scheduled to launch in January.
In the meantime, work progresses on the plug-and-play satellite.
“I think that once we prove the ideas out, they will be applicable to a lot of things beyond satellites,” says Lyke. “When we eventually get enough of the building blocks in a plug-and-play form, the hope is we’ll be able to do what we’re saying — to build a spacecraft in six days.”
Please email your comments to GJean@ndia.org
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