LEO Universe Needs Astronomy-Protecting Regulations, Astronomy Interests Say

SpaceX has worked to make its satellites darker and share position information, but they're not dark enough and the positions aren't as accurate as astronomers need, said Connie Walker, a scientist at the National Science Foundation's National Optical-Infrared Astronomy Research Laboratory. SpaceX didn't comment. There's no guarantee other low earth orbit (LEO) operators will follow the example of major operators, Walker said. The challenge is that satellite constellation impacts on optical and radio astronomy are largely unregulated, something the astronomy world "hope[s] to change," especially since there could be upward of 100,000 satellites in orbit by 2028, she said.

The coordination agreements between satellite operators and the National Science Foundation are starting to include protection of radio astronomy bands and efforts to reduce reflected sunlight, said Richard Green, University of Arizona astronomer and co-chair of the American Astronomical Society (AAS) satellite constellations policy subgroup. But regulations "would codify those good intentions" and set norms for new entrants, he said. "Voluntary cooperation is just that," he said.

Europe approaches such orbital concerns from an environmental perspective, Green said. There are defensible arguments that LEO actions affect Earth’s environment, such as if debris falls on the planet, he said. The National Environmental Policy Act would be the main vehicle for tackling those issues in the U.S., though a NEPA environmental impact statement would be an onerous and costly burden, he said. The Massachusetts Institute of Technology and the Swiss Federal Institute of Technology of Lausanne have partnered on a Space Sustainability Rating, a sort of LEED rating for space operations, and there’s an effort to get astronomy mitigation included in that, Green said. The U.N. Commission on Peaceful Uses of Outer Space’s Scientific and Technical Subcommittee will have an agenda item on astronomical impacts at its next full meeting, he said, saying suggestions from it could become a model for nations.

Astronomers also see an opportunity to tie the issue of misdirected radiation into space sustainability via the Satellite and Telecommunications Streamlining Act, which House Commerce leadership rolled out earlier this year (see 2202110064), Green said. He said AAS is pushing to get language included in it requiring that aggregate effects of constellations to be taken into account for FCC licensing,

The Rubin Observatory, under construction in Chile and expected to go online in 2024, will be particularly sensitive to satellites leaving streaks in its images, Walker said. She said software can fix streaks in astronomical images sometimes, but most twilight exposures will have a streak. Scheduling observations can also sometimes avoid satellites, but satellite forecasting isn't accurate or precise enough to be completely effective, she said. There also are trade-offs in survey depth, she said.

The International Astronomical Union's Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference, launched this spring, is creating a hub for collection and analysis of satellite observations and software tools, plus hubs working on policy and on technology, Walker said. Its efforts include working with satellite operators to set target brightness levels and other mitigation parameters, she said. It also will push regulators to consider aggregate cumulative impacts in their reviews and be active in policy discussions on applying environmental laws to LEO and mitigation of astronomy harm as a licensing requirement, she said.

This generation of LEO interest is different from past ones, as the applications creating demand are particularly well suited for LEO, said satellite consultant Patricia Cooper, previously SpaceX head-government affairs. She said not all constellations will be problematic for astronomy, given there is a diversity of space architectures, altitudes, designs and operating approaches. Brightness and visibility mitigations are still in the early stage of technical development, she said. The IAU center industry and tech hub has been advancing mitigation solutions and encouraging satellite operators to commit to best practices and mitigation techniques, she said. It received commitments from some significant constellation projects including SpaceX, OneWeb and Amazon’s Kuiper, she said.

Astronomers need better access to accurate overflight information, said Mark Mulholland, a Mitre contractor in Commerce’s Office of Space Commerce. For tracking they often use DOD-provided two-line element sets, and those are “often off by a country mile,” he said. He said Commerce commercial space awareness data would be better. He said there also should be more resources put into research on less-reflective materials that don’t degrade satellite performance or increase costs. He said research is needed into design and operational techniques that minimize harmful radio frequency interference.