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Supriya chakrabarti, professor of physics, University of Massachusetts Lowell
It seems that every week another rocket is launched into space carrying rovers to Mars, tourists or, more often, satellites. The idea that “space is cluttered“has been around for a few years now, but how crowded is it? And how much is it going to be?
I am a physics teacher and director of the Space Science and Technology Center at the University of Massachusetts, Lowell. Many satellites in orbit have died and burned in the atmosphere, but thousands remain. Groups this track satellite launches don’t always report the exact same numbers, but the overall trend is clear and amazing.
Since the Soviet Union launched Sputnik – the first man-made satellite – in 1957, humanity has steadily put more and more objects into orbit every year. During the second half of the 20th century, there was slow but steady growth, with around 60 to 100 satellites launched each year until the early 2010s.
But since then, the pace has accelerated considerably.
By 2020, 114 launches have transported approximately 1,300 satellites into space, for the first time surpassing the threshold of 1,000 new satellites per year. But no year in the past compares to 2021. As of September 16, about 1,400 new satellites have already started circling the Earth, and this will only increase as the year progresses. This month, SpaceX deployed 51 more Starlink satellites into orbit.
Small satellites, easy access to orbit
There are two main reasons for this exponential growth. First, it has never been easier to send a satellite into space. For example, on August 29, 2021, a SpaceX rocket was carrying several satellites, including one built by my students – to the International Space Station. On October 11, 2021, these satellites will deploy into orbit and the number of satellites will increase again.
The second reason is that rockets can carry more satellites more easily – and at lower cost – than ever before. This increase is not due to the fact that rockets are getting more powerful. On the contrary, satellites have become smaller thanks to the electronic revolution. The vast majority – 94% – of all spacecraft launched in 2020 were small satellites – satellites weighing less than about 1,320 pounds (600 kilograms).
The majority of these satellites are used for Earth observation or for communications and the Internet. In an effort to bring the Internet to underserved areas of the globe, two private companies, Starlink by SpaceX and OneWeb together, launched nearly 1,000 small satellites in 2020 alone. They are each plans to launch more than 40,000 satellites in the years to come to create what are called “mega-constellations” in low Earth orbit.
Several other companies are eyeing this $ 1 trillion market, including Amazon with its Kuiper project.
A crowded sky
With the enormous growth of satellites, fears of a crowded sky are starting to come true. A day after SpaceX launched its first 60 Starlink satellites, astronomers began to see them block the stars. While the impact on visible astronomy is easy to understand, radio astronomers fear they could lose 70% of sensitivity in certain frequencies due to interference from mega-satellite satellites like Starlink.
Experts have studied and discussed the potential problems posed by these constellations and the ways in which satellite companies could answer it . These include reducing the number and brightness of satellites, sharing their location, and supporting better image processing software.
Less than 10 years ago, the democratization of space was a goal to be achieved. Now with student projects on the space station and more than 105 countries with at least one satellite in space, one could argue that this goal is within reach.
Every disruptive technological advance requires updating the rules – or creating new ones. SpaceX has tested ways to reduce the impact of Starlink constellations, and Amazon has announced its intention to desorb its satellites within 355 days of the end of the mission. These and other actions by different stakeholders give me hope that trade, science and human efforts will find lasting solutions to this potential crisis.[The Conversation’s science, health and technology editors pick their favorite stories. Weekly on Wednesdays.]
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