Profile: Gary E. Payton
U.S. Air Force Deputy Undersecretary for Space Programs
Gary Payton has made a career of pushing the space-technology envelope, be it with the U.S. Air Force, NASA or the Missile Defense Agency.
Now, as the deputy to Air Force Undersecretary Ronald Sega, he’s trying not to push quite so hard. The service, awash in budget-busting satellite development programs, unveiled a more conservative approach to space with its 2007 budget request.
Adopted partly in response to congressional warnings that the service was attempting to bite off more than it could chew in space, the new strategy entails more-realistic cost estimates and an incremental approach to technology deployment. It is now a key feature of the Air Force’s top satellite development programs, including the Transformational Satellite (T-Sat) Communications System and Space Radar.
Payton graduated from the Air Force Academy with a degree in astronautical engineering and spent 23 years in uniform, retiring as a colonel. During that period, he served in positions ranging from instructor pilot to spacecraft engineer to payload specialist aboard the space shuttle’s first military flight in 1985.
He spoke recently with Space News staff writer Jeremy Singer.
In recent years, Congress has directed the Air Force to slow the pace of its space development programs, largely to no avail. Has the Air Force finally gotten the message with the 2007 budget request?
Dr. Sega and I share the common approach of incremental deliveries and block-by-block improvements. He and I have talked to members and staffers, and as we talked about this different approach, we got, across the board — authorizers, appropriators, everybody — a very good reception for that approach. So I think we have at least started out on the proper foot.
What does the user community think of the incremental approach to the T-Sat and Space Radar programs?
The Joint Requirements Oversight Council, which vets user requirements, has already blessed the new approach on T-Sat. They have not yet signed off on Space Radar because we have not been able to quantify the ramifications of a less capable first-generation spacecraft, like the number of square kilometers for open-ocean surveillance, or how many synthetic-aperture radar pictures per day it can take. Once we can quantify those kinds of metrics, we can go to the council and have them decide whether or not that is useful enough for them. [Editor’s Note: The council approved the plan for the initial Space Radar satellites Feb. 15, eight days after this interview.]
Despite being less capable than previously envisioned, those satellites will still likely be able to improve the military’s ability to track moving targets, and offer open-ocean surveillance measured in millions of square kilometers, which can’t be done today from aircraft or space.
What other kinds of capabilities might get left off the first-generation Space Radar satellites?
Some of the other tough areas of the Space Radar platform include the solar arrays and batteries. Clearly, the most complicated part of the spacecraft is the radar sensor, which takes a lot of power, especially if you want to do it on the dark side of the Earth where there is no Sun shining on the solar arrays, and you have to have very potent batteries.
That means you have to space-qualify the most capable batteries that we can get our hands on right now, and the most capable ones are probably sitting in your cell phone. Lithium-ion batteries, when it comes to power density, are the best in the world, but they are not space-qualified.
What’s the solution?
For the initial Space Radar satellites, we’re going to go back to more conventional, space-qualified batteries, and not take as many pictures on the dark side of the Earth.
If you have a large demand for battery power, you have to recharge those batteries on the day side of the Earth. So the solar arrays must power the vehicle during imaging on the day side of the Earth, plus recharge the batteries. That means you need very efficient solar arrays. There is legitimate technology for highly efficient solar arrays , but it’s not space-qualified yet. So we can throttle back to space-qualified solar arrays with lower efficiency, but [which] are available off the shelf.
What is your strategy for the follow-on to the Space Based Infrared System missile warning satellites?
We want to keep it simple — a simple spacecraft, a simple sensor. Your intuition will tell you that a simple sensor surrounded by a simple spacecraft will be less expensive and require a smaller, less-expensive launch vehicle. That’s fundamentally what we’re shooting for right now.
What does a simpler missile warning system mean for secondary missions such as technical-intelligence gathering?
You’ve got to have a prioritized list of mission objectives. The Joint Requirements Oversight Council will review the proposed missions.
If you want a spacecraft that handles a single mission, it costs a certain amount and takes a certain amount of time to build. If you want a spacecraft that can do more missions, it may cost more, fly on a bigger, more-expensive launcher and take longer to build. If you want one that does even more missions, it takes longer, costs more and flies on an even bigger launcher. At some point you draw the line and say, “this is how much I’m willing to spend.”
What role could the services’ in-house research laboratories play in the Alternative Infrared Satellite System?
Those types of labs could help develop more-capable focal plane arrays than those used on the Space Based Infrared System satellites, which are more than 10 years old.
In general, in-house labs could help take the inventions out of acquisition programs, and allow those efforts to rely on proven technology by demonstrating lithium-ion batteries or highly efficient solar arrays with small satellites.
Are there any lessons yet from the problems with the National Polar-orbiting Operational Environmental Satellite System?
One of the key lessons is that any program has to minimize the number of different sensors. It’s a difficult choice. Those weather satellites have 13 different sensors from three different federal agencies. Thirteen is too many. You can do more than one. Somewhere in between is the right answer.
For instance, one of the sensors is a large antenna that is listening to the Earth in the radio-frequency spectrum, and it spins at 30 revolutions per minute above the spacecraft. Another sensor right below is a visible imager that has to point at the ground very accurately. So you have this spinning mass whirring and whizzing on top of an optical sensor trying to straight look at the ground.
So you have engineering problems on how you separate the vibration environment from the spinning sensor to the very stable environment of the Earth-facing optical sensor. Those are some of the engineering problems when you have so many sensors on a spacecraft.
Do you expect to field technology incrementally on the next generation of GPS satellites?
Yes. We now plan to buy an initial block of approximately six to nine GPS 3 satellites, but still need to go to the Joint Requirements Oversight Council for approval of the new approach.
We are looking at power and weight on the spacecraft, and you can translate that into technical maturity. What are the most expensive things from a power and weight perspective? What do we lose if we don’t have them in the first increment? If something is technologically easy, but is still heavy and consumes a lot of power, that’s a huge lever on the size of the spacecraft, its power requirements and the launch vehicle. You have to be very careful about what you include in the mission area.
Again, you want to keep it something you can chew and digest.
