Scientists have had about five years to prepare for the effects of SpaceX‘s Starlink constellation, but the first few sets of the satellites still caught them unawares.
SpaceX founder and CEO Elon Musk revealed the concept in January 2015, detailing how the company planned to launch approximately 4,000 broadband satellites to Earth’s low orbit in order to offer low-cost Internet services for people all over the world. The initial numbers have increased since then.
SpaceX has gained permission from the U.S. Federal Communications Commission to launch approximately 12,000 Starlink satellites, and the company has submitted an application to an international radio-frequency regulator for permission of up to 30,000 extra spacecraft.
Almost 200 Starlink satellites are already in the low orbit of the planet, with SpaceX lofting the first set of 60 last May and the second on January 6th.
Immediately after launch, the Starlink satellites seem to form a bright string of lights as they travel across the sky. The formation then breaks up as the crafts move to their final operational altitude of approximately 340 miles (550 kilometers) above Earth. However, some spacecraft remain visible with the naked eye, even from that altitude.
“What surprised everyone — the astronomy community and SpaceX — was how bright their satellites are,” Patrick Seitzer, an astronomy professor emeritus at the University of Michigan, said during a conference at the 235th meeting of the American Astronomical Society (AAS) called “Astronomy Confronts Satellite Constellations.”
“We knew these tens of thousands[-strong] megaconstellations were coming, but based on the sizes and shapes of things currently in orbit, I thought maybe 8th or 9th magnitude,” Seitzer added. “We were not expecting 2nd or 3rd magnitude in the parking orbits, and we were certainly not expecting 4th to 5th magnitudes in the [operational] orbits.”
This unexpected brightness has a few astronomers concerned. The large number of Starlink crafts, as SpaceX plans to launch 1,600 more this year, could seriously affect the ability of telescopes based on the ground to do their work, as Seitzer says.
The eminent mission that will most probably be impacted is the Vera Rubin Observatory, until Monday, known as the Large Synoptic Survey Telescope (LSST), is set to come to life in a few years from now in the Chilean Andes.
“The survey is the most impacted by bright satellite trails because of its wide field of view and extreme sensitivity,” Seitzer said, citing a statement given to him by Vera Rubin Observatory chief scientist Tony Tyson. “The original Starlinks will saturate the LSST’s detectors.”
Satellites are Covered in Special Coating
Starlink’s effects will be seen beyond the astronomical research community, some scientists say. The night sky filled with stars is a worldwide resource, and one of the methods people stay connected with the nature in the world of technology and urbanity, Ruskin Hartley, executive director of the International Dark Sky Association, said.
“The night sky is the ultimate public good; it’s our ultimate commons,” Hartley explained during the news conference. “No one individual can protect it. And the flip side, I believe, [is] no one individual should be allowed to despoil that.”
Scientists have expressed their concerns to SpaceX, and the company has been very responsive, Jeffrey Hall, the director of Lowell Observatory in Flagstaff, Arizona said.
“We have not had to cajole SpaceX in any way; they’ve been very receptive, very proactive, in holding roughly monthly telecons with us,” Hall said during the news conference.
“It’s been a little more staying in touch than making a lot of progress on mitigation,” Hall said.
SpaceX officials have shown the desire to mitigate, and they have recently addressed this issue. For instance, Patricia Cooper, SpaceX’s vice president of satellite government issues, detailed a paper during the AAS scientific assembly about megaconstellations at Wednesday’s conference.
One of the 60 spacecraft that lofted on Monday features a special coating created specifically to reduce its brightness. If the material has no impact on the craft’s performance, this measure could eventually become the norm across the Starlink constellation.