WASHINGTON — A bill introduced in the U.S. Senate would create a new center to protect astronomy from interference from satellite constellations, while advancing existing efforts by organizations and companies.
The Dark and Quiet Skies Act of 2024, introduced on August 1 by Senators John Hickenlooper (D-Colorado) and Mike Crapo (R-Idaho), would direct the National Institute of Standards and Technology (NIST) to establish a “center of excellence” dedicated to mitigating light and radio frequency interference from satellites in astronomical observations.
“Light and radio pollution from satellites keep the secrets of space out of our reach,” Hickenlooper said in a statement on the bill Aug. 5. “Preserving the darkness of the night sky will advance our research.”
The center would be overseen by NIST but operated by an outside entity such as a nonprofit organization or university. It would work with both astronomers and satellite operators to develop best practices for mitigating interference caused by satellites in the optical and infrared wavelengths from reflected sunlight and in the radio wavelengths from the satellites’ transmissions.
The center would also conduct “transdisciplinary research, development, and demonstration projects” on ways to reduce satellite interference. The center would work with industry to disseminate voluntary guidelines but would have no regulatory authority. The bill allocates $20 million to the center for fiscal years 2025 through 2029.
If passed, the center would join other initiatives launched over the past five years to address concerns about the disruption that large satellite constellations pose to astronomy. Astronomers raised the alarm about this threat after the launch of the first SpaceX Starlink satellites in May 2019, which were visible to the naked eye in a sort of “string of pearls” in the days following the launch. SpaceX has since launched more than 6,800 Starlink satellites, and thousands more are planned by that company and other constellation developers.
One such initiative is the International Astronomical Union’s Center for the Protection of Dark and Quiet Skies from Disturbance by Satellite Constellations (IAU CPS). This center is involved in several projects, including the development of software tools for astronomers, as well as outreach and policy-making.
The IAU announced on August 8 that CPS had received a $750,000 grant from the U.S. National Science Foundation to support this work. The money will be used to develop software that will allow astronomers to predict which satellites will fly through the field of view of their observations so they can avoid the worst interference.
“This NSF funding will improve the observatories’ ability to reduce the frequency of satellite flybys that interfere with observations, thereby improving scientific outcomes,” said Connie Walker, co-director of the IAU CPS, in a statement about the grant.
The project will be particularly useful for the Vera C. Rubin Observatory in Chile, which is preparing for a 10-year survey of the night sky that will discover objects ranging from near-Earth asteroids to distant galaxies. Interference from satellites, particularly those bright enough to blind Rubin’s sensitive camera, is a concern for astronomers.
“The Rubin Observatory is about to begin a groundbreaking, decade-long survey of the night sky and will see plenty of streaks, glitters and flares from man-made satellites,” said Meredith Rawls, an astronomer at the University of Washington who co-leads the CPS SatHub project that will develop the software. “This funding will allow us to better understand and mitigate the resulting science impacts in the Rubin data products.”
There is also direct collaboration between astronomers and satellite operators. SpaceX announced on August 9 that it had worked with the NSF and the National Radio Astronomy Observatory (NRAO) on a technique that the company will implement on its Starlink satellites to avoid interference with the NRAO’s radio observatories.
This technique, called Telescope Boresight Avoidance, involves a “real-time data exchange framework” between Starlink and radio observatories so that SpaceX knows the orientation, or boresight, of the radio telescopes. The Starlink satellites then adjust their beam patterns as they pass overhead to avoid funneling signals into the telescope.
“This method of avoiding the target line protects the telescope’s observations while ensuring Starlink service remains uninterrupted for customers near the telescope,” SpaceX said. The system is currently live for NRAO’s Very Large Array radio observatory in New Mexico and the company said it is working with other radio telescopes to implement it.
“The innovative methods developed jointly by NSF NRAO and SpaceX provide a clear path for others to follow to improve rural access to high-speed internet while protecting the scientific and economic benefits of nearby radio astronomy facilities,” said Ashley VanderLey, senior adviser for facilities in NSF’s Division of Astronomical Sciences, in an NSF statement about the effort.
