New Problems for Radio Astronomy: The Rise of Starlink and the Loss of Arecibo

It appears as if technology is hitting astronomy in two directions: Many who enjoy imaging the sky are finding more streaks brought on by what is becoming an untold number of “Starlink” satellites that streak through what should be a pristine view of the celestial sphere. Originally, when the Motorola series of satellite flares would occur, we used to alert the public on the brightness in a specific area, which would last just a few seconds, then disappear; now, however, with the launch of these Starlink satellites, the “streaks” won’t disappear. SpaceX has already sent up hundreds of these satellites, and will continue to do so.

Most of these satellites, normally just a few inches on a side, have an ultimate goal to provide internet service to remote areas. It does appear that SpaceX has decided to help the brightness issue, as it continues to launch more of these; at present, there are about 700 of the 1440 already set, and it apparently has been approved for 12,000 more (Daniel Cleary, Satellite Swarm Threatens Radio Array, Science, 16 October 2020). SpaceX has changed the orientation of them in their orbits, painted them darker, and added “visors” to lower reflection. Of course, besides our own observing and photographic efforts, professional observatories are worried, including Chile’s Vera C. Rubin Observatory.

In addition to optical problems brought on by these tiny orbiters, they are also creating havoc with the radio spectrum. Most notably, by sending radio signals downward, they would interfere with the work being done by the Square Kilometre Array (SKA) in South Africa, which is planned to be completed later this decade. The United Nations Office for Outer Space Affairs is looking into this double problem of astronomers within the Electromagnetic Spectrum, not only for science but also for the general public and wildlife concerns. If nothing is done, the SKA could lose 70% of its sensitivity; more of these satellites could potentially render this, and other radio observatories, basically silent in certain frequencies.

In another, related note: It appears we have to say good-bye to a workhorse of a radio telescope that many of us know, not only for its decades of service, but its presence in movies such as Contact and the James Bond forgettable Goldeneye. Puerto Rico’s 1,000 foot (305 meter) Arecibo Observatory, which up until just recently was the largest radio dish in the world, had a 100-foot hole torn in its dish by an auxiliary cable in August; and, then, just a few weeks ago, one of its main steel cables snapped. This led the National Science Foundation to believe that, even if the damage were repaired, the structure in the long term could still be unstable, and possibly compromise the safety of the workers.

It is unfortunate that a facility such as this, which has been important, not only as a research tool, but a teaching platform for many astronomy graduate students, should be rendered unsafe, after withstanding hurricanes, earthquakes and intense humidity for 57 years; however, the research done there, such as pulsars, gravitational waves, and neutral hydrogen searches, will never be forgotten.