This article was written by site member Tom Urbain. This is the second Galactic Hunter post written by an outside contributor.
What is Starlink?
On April 22, 2020, SpaceX (led by Elon Musk) launched another batch of satellites into space from the Kennedy Space Center in the United States. These satellites have joined the existing “Starlink Constellation” in orbit around the earth since February 2018 and they have had extensive press coverage lately.
During the past few weeks, many people have been posting pictures of the night sky displaying the famous train of 60 satellites from the Starlink program. Many amateur astronomers have voiced their concerns that the luminous streak of satellites across the sky may impair their ability to enjoy the night sky.
But what is Starlink and what is its purpose?
Starlink, The Satellite Constellation
In essence, Starlink’s satellite constellation is designed to provide cheap Internet access to any part of the world… even to the most recluse part of the Planet.
Elon Musk is going big with this project: he plans to put 12,000 satellites into orbit by 2025 and 42,000 satellites into orbit by 2030 if he obtains the necessary authorizations. Each satellite will be placed in a low orbit, between 350 km and 1500 km in altitude. This makes it possible, in terms of telecommunications, to have a better performance in terms of internet speed. Latency is much lower compared to geostationary satellites based at 36,000 km altitude.
While this sounds good on paper, is it really worth it? Starlink does raise some concerns in the scientific community.
A visual impact on stargazing
There has been an increasing number of reports and images posted on social media showing Starlink satellites traveling through the night sky. Professional and amateur astronomers are mobilizing, questioning and seeking answers about the visual impact this satellite network will have on stargazing. Many fears that the increasing number of satellites will invade the night sky and make telescopic observation very difficult.
It turns out that each satellite, as the sunlight reflects off its solar panel, creates a flash of light for a few seconds, day and night. Like a star that grows very quickly, with intense light, only to disappear afterwards. It’s easy to understand how badly this may impact the ability to observe planets, stars and galaxies as well as taking pictures of them.
A “Noisy” impact on radio astronomy
Another subject to consider is the radio waves emitted by Starlink satellites... Indeed, astronomers also study the radio waves emitted by the stars. It is radio astronomy that has enabled a better understanding of the structure of our galaxy, the evolution of nebulae, the birth of stars, and much more...
This research is carried out by using gigantic dishes measuring up to 500 meters in diameter: radio telescopes.
Because these radio signals coming from the universe are very weak, there are now concerns that theses telescope’s ability to pick up those signals might be disrupted by the powerful waves emitted by these new satellite arrays.
This would deprive scientists of important data for understanding the Universe.
A Risk of collision
Concerns about possible collision are also rising, as Starlink is not the only project for a constellation of satellites in low orbit. A company called OneWeb is working on its own project and even Amazon is going to launch its satellite constellation, called the Kuiper project. In total, there could be more than 45,000 satellite that could be launched over the next few years, whereas there are currently just over 2,200 satellites around the Earth.
In September 2019, the European Space Agency warned of the increased risk of collisions after having to modify the trajectory of one of their scientific satellites in order to avoid a collision with a Starlink satellite.
This increasing probability of collisions also raises the question of space debris. As satellites travel at speeds close to 30,000 km/h, the slightest incident can generate a very large number of debris, which in turn can hit other objects, leading to a chain reaction.
For now, it seems that SpaceX and a few other companies will go ahead with their plans no matter what. Elon musk keeps stating on Twitter that he is listening to astronomers concerns and that his company his working on various solutions. This includes placing the satellites into a slightly higher orbit, and reducing their reflectivity: parts of the satellite would be darkened to reduce its reflectivity and hence brightness.
But will this be enough?
Big thanks to Tom Urbain for writing this post! You can visit his website here.
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