Mega-constellations have been known to have a dramatic impact on space traffic. Scientists are trying to ensure that they don’t cause a problem and create more debris in our planet’s orbit. Dozens of companies around the world are hoping to place new constellations of tens, hundreds, or thousands of Earth imaging, Internet-of-Things, and communication satellites. Although not all of them are projected to succeed, researchers are still concerned about the increase of satellites and debris in orbit.
Not Enough Space
The amount of satellites in orbit is not the primary concern for these researchers, it’s the fact that we don’t have enough room for them all. There are currently 1,900 active satellites in Earth’s orbit and these mega-constellations could push that number close to 20,000 in the next decade. One of the companies planning on launching satellites is SpaceX.
SpaceX won U.S. Federal Communications Commission approval to launch 4,425 satellites into its Starlink broadband constellation and they are looking to add 7,518 more satellites next year. OneWeb is asking for approval to launch 1,980 broadband satellites to an altitude of 1,200 kilometers and 2,560 into medium Earth orbit.
The Problem With Mega-Constellations
According to Ted Muelhaupt, the associate principal director for The Aerospace Corporation’s systems analysis and simulation division, “if you launch enough satellites to the same altitude, you create something like a shell.” This shell could make the Earth’s lower orbit unusable.
Scientists also fear that with so many mega-constellations in low Earth orbit, we may be faced with a worst-case scenario known as the Kessler Syndrome. Too many satellites can result in even more debris and a larger chance of a collision.
There have already been a number of collisions such as the 2009 collision between an Iridium satellite and a Russian Cosmos spacecraft. At those higher altitudes, the debris created would be long-lived because of the lack of atmospheric drag.
Avoiding The Kessler Syndrome
Jer Chyi Liou, NASA Orbital Debris program manager, believes that “to prevent a serious long-term debris problem, 99 percent of spacecraft must deorbit within five years after they complete operations.” However, this is a lot more complicated than it sounds.
Satellites need to be reliable enough to stay in orbit from the time they were launched until they are done with their mission. They will need enough fuel to perform their end-of-life maneuvers like the Cassini spacecraft when it was done orbiting Saturn. Brian Holz, CEO of the OneWeb/Airbus manufacturing joint venture has put a lot of work into de-orbiting his satellites. “We’ve put extra hardware into the system to improve the reliability of that deorbit process. We’re also committing to put a small adapter device on each spacecraft that will allow those spacecraft, in the small probability that one of them dies on the way down, to be grabbed by a small chase vehicle and pulled out of orbit.”
If other companies follow Holz’s lead then we may be able to clear Earth’s lower orbit of old satellites and space debris over the next decade. It will cost a lot of money but it’s something our environment and our planet desperately needs.