When approved by the Federal Communications Commission Amazon’s plans for the Kuiper constellation, a plan to launch 3,236 low-earth satellites (LEO), the astronomy world raised a collective eyebrow. Low-Earth satellites move rapidly across the night sky like small stars – which can interfere with the types of long exposures astronomical observatories have to make to capture distant astronomical objects. And the more satellites orbiting the Earth, the more likely it is that one or more observations will interfere.
Anecdotally, astronomers have shared their fears over the last few years, sometimes publicly speaking, and a few reports have attempted to quantify the impact. Well, an in-depth new report of a working group of astronomers released by the American Astronomical Society shows how these satellites can drastically change the scope of astronomy work on Earth.
Specifically, astronomers state that existing satellites, including the 538 SpaceX satellites, as well as future ones, “fundamentally change the way astronomers can plan and execute observations.” In other words, the field of astronomy poses an existential threat.
“With tens of thousands of LEOs [satellites], no combination of mitigations can prevent the effects of satellite paths on the scientific programs of the next generation of optical astronomy devices, “the report states.
The authors warn that, even in this last year, “the sky has changed,” as a “growing number of satellite paths contaminating astronomical images.” The risk of contaminated data, they write, can be difficult to predict and limit: “A light satellite crossing near a long spectrograph slot. . . can destroy the entire exposure because it is not known a priori which observations are contaminated, forcing a repeat of exposure as possible loss of scientific opportunity. ”
And this is just the beginning. SpaceX intends to send a total of 25,000 communications satellites for their planned Starlink constellation; it is currently approved to launch 12,000. As of February 2020, there were approximately 5,500 satellites in total in space, of which 2,300 still functioning. The number of satellites is expected to grow to tens of thousands in the coming years, thanks to companies such as Amazon, SpaceX and OneWeb. Their satellite constellations are part of plans to give broadband internet access to everyone on earth.
But at what price for science? As the report explains, the success of astronomical research depends on the ability to observe each part of the sky with the same quality of sight. Specifically, studies such as observing star populations in the Milky Way and nearby galaxies, and searching for potentially dangerous near-Earth objects, could be undermined by more LEO satellites, especially considering how time-sensitive these observations can be.
“If, for example, a near-Earth object is not found, its orbital parameters will be lost,” the authors of the report state. “If the transit of a potential candidate for super-Earth exoplanet is missed, the orbital timing may not be recovered.”
Writers of the report cited OneWeb as a particularly problematic constellation due to the high altitude at 1200 kilometers above the earth.
“Constellations at high altitudes, such as the 1200 km OneWeb constellation, present particularly serious challenges; they will be visible all night long in summer and significant fractions of the night in winter, autumn and spring, and will be negative. have effects on almost all observation programs, “the report said, referring to” twilight observations “, which are often important when it comes to searching for Earth-threatening asteroids and comets.
The report contains ten recommendations to limit the impact of satellites on astronomical surveys, including the launch of “lesser” or no LEO satellites. “As impractical as it may be, this is the only option identified that can achieve zero astronomical impact, “a press release on the report stated. Other ways include deploy satellites at orbital heights, darken the satellites and find a way to minimize satellite paths.
The authors of the report also note that these commercial satellites can spoil star nights for amateur astronomers.
The report comes at a time when the capitalists of the earth are preparing themselves commercialize space, and rapid technological advances advance our knowledge of the universe.
“Recent technological developments in astronomical research – particularly cameras with wide fields of view on large optical infrared telescopes – coincide with the rapid deployment of many thousands of LEOsats by companies inventing new space-based communications technologies,” said Connie Walker, an employee to the report and an astronomer at NOIRLab in Tucson, Arizona, said.
Despite the tension, it is hoped that this report will inspire both scientists and commercial satellite operators to work together.
“Although we are still at an early stage of understanding and addressing the threats to astronomy posed by large satellite constellations, we have made good progress and have good reason to hope for a positive outcome,” said AAS President Paula Szkody in a statement.
