Credit: Iridium

WASHINGTON — With his second-generation constellation safely in orbit and more than 60 first-generation satellites, Iridium Chief Executive Matt Desch thinks it’s a good time get outspoken about orbital debris.

Desch admits right away that he can be accused of being disingenuous. Of his own satellite constellation — 95 satellites launched between 1997 and 2002 — more than 20% failed in orbit and will remain there for a century and now he wants to tighten regulations for debris mitigation?

“It’s a valid criticism,” Desch said. “It’s fair that people would say that. But tell me where I’m wrong in my statements about the problem.”

Iridium several years ago agreed to open its orbital data books to NASA and the U.S. Air Force — on a nondisclosure basis — to give these government agencies data on the Iridium constellation’s orbital data.

The company has one of its employees stationed at the Combined Space Operations Center (CSpOC) at Vandenberg Air Force Base, California.

In an interview here May 8 during the Satellite 2019 conference, Desch said Iridium receives multiple collision-alert warnings from CSpOC every week. It’s not something he likes to trumpet, he said, because too many people will either conclude the space traffic management issue is not a problem, or draw the opposite conclusion that low Earth orbit is a death trap for satellites.

“The situation is manageable right now,” Desch said. “We’re not talking about a situation like in the movie ‘Gravity.’ But if we want it to remain controllable, we need to act.”

Desch’s main issue is that the reliability forecasts made by constellation operators will prove far too optimistic, leaving multiple dead satellites in orbits at 1,000 kilometers and higher.

“From that altitude, if your satellite becomes basically a rock in orbit, it’s up there for 1,000 years,” he said. “If you have a constellation of 1,000 satellites, and you lose 15% of them, that’s 150 satellites.”

Desch does not pretend to have a detailed regulatory proposal on hand. But he said the industry needs one, and that it should include a requirement that satellite and rocket builders be grounded after an in-orbit failure until they have determined the failure’s cause.

This happens among launch-service providers because customers demand it. But for an operator of a constellation that can sustain the loss of 15% of its fleet and keep the business going, there is no similar pressure. Regulation could change that.

He is also in favor of obliging satellites flying higher than the International Space Station — around 400 kilometers — to carry on-board propulsion.

That is one of the proposals made by the U.S. Federal Communications Commission (FCC). It has not won universal support. The U.S. Defense Department worries that if such a rule is not tightly coupled with a requirement for a secure, encrypted satellite uplink, it could increase the possibility of satellites being hijacked to become weapons.

Desch said he would support such a coupling to require encrypted uplinks along with on-board propulsion.

But these measures would not necessarily reduce the number of “rocks” created when satellites fail in orbit.

Desch concedes the point. For now, there is no definitive answer in the absence of a service that can grab and properly dispose of dead satellites in low Earth orbit.

The OneWeb constellation’s 150-kilogram satellites, to orbit at 1,200 kilometers, include a grapple-friendly fixture in the hope that one day such an in-orbit waste-disposal system might be credible.