NASA has made a formal comment on a U.S. company’s request to build a super-large satellite cluster at an altitude of more than 720 kilometers above the Earth’s surface: the agency opposes the plan for fear of a collision. This appears to be the first time NASA has publicly commented on such a market access application, which is awaiting approval by the Federal Communications Commission.
“NASA submitted this letter during its public comments to better understand NASA’s concerns about its assets in orbit to further reduce the risk of collisions and benefit all stakeholders,” wrote Samantha Fonder, an engineer at the space agency.
At issue is plans by AST and Science to build a constellation of more than 240 large satellites, essentially deploying “base stations” in space to provide 4G and possibly 5G broadband connections directly to mobile phones on Earth. The Midland, Texas-based company calls its constellation “SpaceMobile” and has raised about $120 million.
Most notably, the proposed height of the SpaceMobile constellation is located near “A-Train”. A-Train is a group of 10 Earth science monitoring satellites operated by NASA and the U.S. Geological Survey, as well as partners in France and Japan. “The historical experience of the A-Train constellation shows that this particular space region often produces a large number of points of binding between space objects,” NASA said in the letter.
Satellites are also very large in size. In order to provide services, AST plans to build a spacecraft with a large phased array antenna – 900 square meters. According to NASA, when planning a potential meeting with other satellites and debris in this orbit, this would require a “hard body radius” of 30 meters, or 10 times larger than other satellites.
NASA says it will be extremely labory to maneuver around the proposed SpaceMobile constellation. “For a complete constellation of 243 satellites, 1,500 mitigation operations, perhaps 15,000 planning activities, can be expected each year,” the space agency said. “This would amount to four exercises and 40 active planning activities on any given day.”
Finally, the space agency is concerned because AST has never built a satellite that is close to a ton or larger in size and will fill its constellations. In view of this inexperionsiveness, it is expected that 10 per cent or more of the satellites may fail, making it impossible for them to operate to avoid collisions. NASA considers the risk of a catastrophic collision to be “unacceptablely high.”
NASA submitted its comments on October 30, which ended Monday. Most of the other comments on the AST application are supportive.
In response to questions about NASA’s comments, AST said it would work with NASA to improve its concerns. “We have reviewed NASA’s letters and believe we can work with them to address their concerns, including clarifying the design of AST’s constellations, effectively managing orbital debris, and keeping NASA and other orbital assets safe,” said Raymond Sedwick, chief scientist at AST Space Systems.
So why does the FCC have to deal with this problem? Responsibility for U.S. space activities is spread across several federal agencies, but the FCC manages the spectrum. In this case, AST has obtained permission to use the V-band spectrum from Papua New Guinea. However, to enter the U.S. market and sell its services, AST must still obtain permission from the FCC.
When it comes to super-large constellations — including SpaceX’s Starlink and OneWeb — the FCC has been considering debris when hundreds or even thousands of new satellites are put into low-Earth orbit. In general, the FCC has been very forgiving in issuing spectrum licenses to satellite operators. “I don’t know of any examples of the FCC refusing to issue such permits,” said Brian Weeden, a satellite expert at the Safe World Foundation. “They’re trying to be business-friendly and encourage companies to do business in the U.S.”
However, the FCC has been using its spectrum powers to consider rules requiring satellite operators to compensate the government for potential accidents to mitigate debris. The comment period for the proposed rules was first published in April and ended last month. It’s unclear what the final rules will look like, but satellite operators have characterted some of the ideas as too cumbersome. Finally, it’s unclear how the FCC will handle NASA’s concerns.
In the big picture, Weeden said, the storm between NASA and AST is more evidence that the U.S. government — and other space nations around the world — needs to do a better job of keeping low-Earth orbit as debris-free as possible. There is currently no government agency dedicated to ensuring the safety of low-Earth orbit, and existing models have failed to fully capture threats from old and new satellites, second stages of used rockets and known debris. So, in a sense, he argues, regulators are blindly moving as all the super-large constellations fly into space today.
“We should have done a lot of this over the last 10 years, ” he said. “From the point of view of government policy surveillance, we are already behind the power curve.”