Photo: NASA image of Earth taken from the International Space Station

The U.S. Space Force is examining Very Low Earth Orbit (VLEO) for possible future use. LEO satellites typically orbit about 500 miles above Earth, while VLEO satellites are to operate at half that altitude and lower.

“We’re seeing more domains within space becoming relevant, and I think VLEO is one of them,” Gillian Bussey, the Space Force’s deputy chief science officer, said during question and answer at a panel on service innovation at the National Defense Industrial Association’s Emerging Technologies conference in Washington, D.C., on Aug. 27.

“It’s not really entirely clear exactly how we would use VLEO, or exactly what the threat is expected to be there, but there are some things about it that are interesting,” she said. “I can’t go into all of those things, but one, in particular, is ‘r squared’ is less, and when ‘r squared’ is less you need less power. You have less losses for communications, for collection of signals, for imaging things so that’s one potential advantage. It’s also harder to do space domain awareness in VLEO because they just have a smaller ground track, and you need more assets to be able to track these things.”

“R” is the variable for distance, and “free space loss” of communications — FSPL denoted by distance squared — is less in VLEO because of the shorter distance between transmitting and receiving antennas.

“But there are certainly some technology challenges [with VLEO],” Bussey said. “Being in VLEO, you have to overcome the drag. It’s a very toxic environment because of the disassociated oxygen, but it’s something we are certainly looking at in terms of what we can get from operating there and also whether we need to be prepared to do space domain awareness of that regime. I’d also say that when you look at Chinese writings and how they view space and air, they see it as a continuum. In the U.S., we say the Von Karman line, above that 100 kilometers you’re in space, below that in air, whereas I’m not sure our adversaries see it that way. They’re pursuing technologies that blend those two domains and operate seamlessly between them. That’s something that we may also need to consider in terms of taking advantage of those seams and taking advantage of that blended area, as well as being prepared for threats that come and use that space.”

Space Force has contracted with Rocket Lab USA for a VLEO mission and the Defense Advanced Research Projects Agency has done the same with Redwire. In March, Denver’s Albedo Space heralded the launch of the company’s Clarity-1 VLEO imaging satellite as the first VLEO commercial bird.

This story was first published by Defense Daily