BlueWalker 3, a huge and bright communication satellite, is really alarming for astronomers
This article was originally published on The conversation. (opens in new tab) The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.
Michael J.I. Brown (opens in new tab)associate professor of astronomy, Monash University
The night sky is a shared wilderness. On a dark night, away from the city lights, you can see the stars the same way your ancestors did centuries ago. You can see the … Milky Way and the constellations associated with stories of mythical hunters, sisters and journeys.
But like any wilderness, the night sky can be polluted. Ever since Sputnik 1 in 1957 thousands satellites and pieces of space junk have been launched into orbit.
For now, satellites traversing the night sky are largely a curiosity. But with the advent of satellite constellations – with hundreds or thousands of satellites – this could change.
Related: 10 Weird Things About SpaceX’s Starlink Internet Satellites
The recent launch of blue walker 3 (opens in new tab), a prototype satellite constellation, raises the prospect of bright satellites contaminating our night sky. With 64 square meters it is the largest commercial communications satellite (opens in new tab) in low Earth orbit – and very bright.
Pollution of the night sky
While spotting satellites in the night sky has been a curiosity, the increasing number of satellites in orbit means that pollution of the night sky could become a serious problem.
On a clear night, especially near dusk, you can see satellites traveling across the night sky. These satellites are in low Earth orbit, only a few hundred kilometers higher Soil and travels nearly 8 kilometers per second.
Applications (opens in new tab) and websites (opens in new tab) you can identify or predict the arrival of certain satellites overhead. And it’s really nice to see International Space Station traveling by, realizing that there is a crew of astronauts sitting on that bright spot.
But in recent years, the pace of satellite launches has accelerated. SpaceX has made satellite launches cheaper, and it has launched thousands Starlink satellites that provide internet services.
Each launches about 50 Starlink satellites into orbit Falcon 9 rocket, and initially produced a bright train of satellites. These were initially produced UFO reports (opens in new tab)but are now sufficiently common not to be particularly newsworthy.
Once the Starlink satellites spread out and go to their operational orbits, they will approach the limit of what can be seen with the naked eye.
However, such satellites are bright enough to produce trails in telescope images. These paths override the stars and galaxies below, which can only be remedied by taking additional photos. Brief transients, such as a brief flash of a gamma ray burst (opens in new tab)may be lost.
blue walker 3
While Starlink is the largest satellite constellation in service, with thousands of satellites in orbit, others are planned.
Amazon’s Blue Origin plans to launch more than 3,200 Project Cooper (opens in new tab) satellites, and AST Space Mobile (opens in new tab) launch plans 100 Blue Bird (opens in new tab) satellites (and maybe more).
The recently launched BlueBird prototype, BlueWalker 3, has really raised the alarm among astronomers.
Although BlueWalker 3 was quite weak at first, it unfolded a communications array of 64 square meters – about the size of a squash court. This vast surface is very good at reflecting sunlight and BlueWalker 3 is now as bright as some of the brightest stars in the night sky.
It is possible the operational BlueBird satellites could be even bigger (opens in new tab) and brighter.
Large numbers of satellites this bright can be bad – very bad. If there were thousands of satellites that were this bright, sometimes you wouldn’t be able to look at the night sky without seeing bright satellites.
We would lose that sense of wilderness, with an almost constant reminder of technology in our air.
There could be a major impact on professional astronomy. Brighter satellites do more damage to astronomical images than weaker satellites.
In addition, many of these satellites transmit at radio frequencies that can interfere with radio astronomy Radio waves (opens in new tab) over remote locations radio observatories observe the sky (opens in new tab).
An abyss?
What happens next is uncertain. The The International Astronomical Union has communicated its alarm about satellite constellations, and BlueWalker 3 in particular.
However, the adoption of satellite constellations by the US Federal Communications Commission (opens in new tab) has taken relatively little account of the impact on the environment.
This has recently been labeled a major problem by the GGD United States Government Accountability Office (opens in new tab)but whether this leads to concrete change is unclear.
Perhaps we are on the edge of an abyss. Will the night sky be littered with bright artificial satellites for the sake of the internet or 5G? Or do we retreat and preserve the night sky as a globally shared wilderness?
This article has been republished from The conversation (opens in new tab) under a Creative Commons license. Read the original article (opens in new tab).
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