By Monique Conrod
SpaceX—the American technology company—launched 60 satellites into space on January 29. (A satellite is an object that orbits a planet. Some are natural satellites, like the moon. Others are artificial, like the ones launched by SpaceX.)
SpaceX plans to create a network of 12,000 satellites. The company says that the network, known as Starlink, will help provide better Internet service to remote parts of the world.
But astronomers say the growing number of satellites orbiting the Earth is making it harder for them to observe and learn from the universe.
Satellites are made of metal that reflects sunlight. This makes them show up in the night sky as bright, slow-moving dots. After the launch in November, the Starlink satellites appeared in images taken by telescopes and deep-space cameras as a trail of bright lights streaking across the sky.
The Starlink satellites take three to five minutes to cross the viewing area of a telescope. During that time, they may pass directly in front of the object an astronomer is trying to look at, hiding it from view. Also, the light from the satellites is so bright, it makes it impossible to see the fainter light of distant stars and planets.
Astronomers learn about space by using large telescopes and special cameras to observe light coming from very far away. The information they collect can help them understand things like how galaxies are formed or which planets might be able to support life.
Some astronomers also use radio telescopes, which record radio waves coming from space. This makes it possible to study things that give off low energy and would not show up as light—like dust and gases. In April 2019, astronomers used information collected by several radio telescopes to produce the first image of a black hole.
Large groups of satellites—known as “satellite constellations”—give off radio signals of their own and reflect radio waves coming from Earth. These extra signals interfere with radio waves coming from further away in the galaxy. While it might be possible to build satellites with surfaces that don’t reflect light, it will be very difficult to make satellites that don’t interfere with radio waves.
SpaceX began launching batches of Starlink satellites in 2019. The company is planning as many as 22 more launches in 2020. Eventually, the company would like to put 30,000 satellites into orbit around the Earth. Other companies also want to create satellite constellations of their own.
People have been launching satellites into space since 1957. They serve many useful purposes. Some are an important part of communications networks, like cellphones, TV, and Internet. Others are used to track weather and climate information, create maps of the Earth, operate navigation systems like GPS, and take photos of the Earth, sun, planets and deep space. The International Space Station is a kind of satellite, with room for people to live on it.
Right now, there are about 1,000 artificial satellites orbiting the Earth. But with companies planning to launch thousands more, astronomers are worried about the effect all of those satellites will have on their ability to study the universe. More satellites orbiting the Earth also means there are more chances of collisions, and more “space junk” floating around the Earth when the satellites stop working.
There are no rules about who can launch a satellite, or how many can orbit the Earth at one time. The International Astronomical Union (IAU) is a group made up of professional astronomers from all over the world. IAU members want to work with the companies that design and launch satellites and the governments that make laws and regulations. They say it’s important to study the impact of having so many satellites and to make rules to protect the night sky.
Think and Discuss
There are currently no rules about who can launch a satellite or how many can be orbiting the Earth. Should there be? If so, who do you think would put the rules in place? Who would enforce them, and how?
Make a T-chart and label one side “pros” (good things) and the other side “cons” (bad things). List five things in each column about satellite launches.
This article mentions two types of satellites, real and artificial. Find out some information about both types. What are the similarities and differences?
Satellite Facts for Kids http://www.sciencekids.co.nz/sciencefacts/space/satellites.html
A video about the Canadian Space Agency’s RADARSAT Constellation Mission Earth observation satellites http://www.asc-csa.gc.ca/eng/satellites/radarsat/what-is-rcm.asp
Enter the name of your town or city to find out what you can see in your night sky. https://www.timeanddate.com/astronomy/night/
This NASA web page describes a SpaceX mission to send supplies to the International Space Station in December. https://blogs.nasa.gov/spacex/2019/12/