NASA rejects a new mega-constellation and points to the risk of...

NASA has officially commented (PDF) on a request from a US company to build a mega-constellation of satellites at an altitude of 720 km above the earth’s surface, citing concerns about collisions. This appears to be the first time NASA has publicly commented on such a request for market access pending with the Federal Communications Commission.

“NASA is filing this letter during the public comment phase to better understand NASA’s concerns about its orbiting assets and to further reduce the risk of collisions for the mutual benefit of all parties,” wrote Samantha Fonder. an engineer for the space agency.

It is about plans from AST & Science to build a constellation of more than 240 large satellites and essentially deploy “cell towers” in space to provide 4G and possibly 5G broadband connectivity directly to cell phones on Earth. The Midland, Texas-based company calls its constellation “SpaceMobile” and has raised an estimated US $ 120 million.

The space agency felt compelled to comment on AST’s proposal for several reasons. Most notably, the proposed altitude for the SpaceMobile constellation is near the “A-Train,” a group of 10 geoscientific surveillance satellites operated by NASA and the US Geological Survey, as well as partners in France and Japan. “Historical experience with the A-train constellation has shown that this particular region of space tends to produce a large number of conjunctions between space objects,” the NASA letter said.

They are great too

The satellites are also very large. AST plans to build a spacecraft with large phased array antennas – 900 square feet. According to NASA, when planning possible connections with other satellites and debris in this orbit, a “hard body radius” of 30 meters, ten times larger than that of other satellites, should be prescribed.

Maneuvering around the proposed SpaceMobile constellation would be extraordinarily strenuous, NASA said. “For the complete constellation of 243 satellites, one can count on 1,500 mitigation measures per year and perhaps 15,000 planning activities,” said the space agency. “This would correspond to four maneuvers and 40 active planning activities on a given day.”

Finally, the space agency is concerned because AST has never built a satellite anywhere near the size of the 1-ton or larger vehicles that will populate its constellation. Given this lack of experience, it is expected that 10 percent or more of the satellites will fail and be unable to maneuver to avoid collisions. NASA determined that the risk of a catastrophic collision is “unacceptably high”.

NASA submitted its comment on October 30th, and the comment deadline was Monday. Most of the other comments on AST use were supportive.

In response to a request from Ars about NASA’s filing, AST said it would work with NASA to address their concerns. “We have reviewed NASA’s letter and are confident we can work with them to address their concerns. This includes clarifying AST’s constellation design, which robustly manages orbital debris and keeps NASA and other orbital facilities safe, ”said Raymond Sedwick, AST’s chief scientist for Space Systems.

What is the FCC?

Why is this problem before the Federal Communications Commission? Responsibility for US space activities is shared among several federal agencies, but the FCC manages the spectrum. In this case, AST has already obtained a license to use the spectrum in the V-band of Papua New Guinea (yes, that is legal). However, in order to gain access to the US market and sell its services, AST has yet to obtain approval from the FCC.

When it comes to mega-constellations – including Starlink, OneWeb, and others from SpaceX – the FCC hat I’ve been thinking about the problem of debris when it comes to putting hundreds, if not thousands, of new satellites into low-earth orbit. Hence, it will be interesting to see which direction the FCC is going on this issue as the federal agency has two competing interests.

In general, the FCC has been incredibly tolerant in granting spectrum licenses to satellite operators. “I am not aware of any example of the FCC denying such a license,” said Brian Weeden, satellite expert at the Secure World Foundation. “They are trying to be business-friendly and encourage companies to do business in the US.”

However, the FCC has used its frequency authority to review rules that can reduce debris by asking satellite operators to exempt the government from potential accidents and better maneuver their vehicles. A comment period for these proposed rules, first published in April, ended last month. It’s not clear what the final rules will be, but satellite operators have deemed some of the ideas too burdensome.

Finally, it’s unclear how the FCC will deal with concerns from NASA, which knows a thing or two about space and is speaking for the first time.

By and large, Weeden said, this cloud of dust between NASA and AST is further evidence that the U.S. government – and other space-exploring nations around the world – must do a better job of ensuring that Earth orbit is as free as possible remains of rubble. There is no government agency specifically responsible for keeping Earth orbit safe, and the existing models cannot fully capture the threat from new and old satellites, spent rocket stages, and known debris. In a way, with all the mega-constellations flying into space today, regulators are flying blind, he said.

“We should have done a lot of this work in the last 10 years,” he said. “From a government policy perspective, we are behind the power curve.”