Here on Earth we tend to assume that what goes up must come down, but out in space things operate a little differently. To send a spacecraft or satellite into orbit around the Earth we launch it on a rocket which initially goes straight up, and then propels the object sideways into orbit. Along the way, some used rocket parts and debris detach and remain in orbit.
The objects we launch into space, such as the International Space Station, satellites and space telescopes, continue on in low Earth orbit unless they are damaged or destroyed by collisions with other objects in space. Such collisions, in turn, result in smaller, more numerous space debris that can do further damage to other objects out there. And the destruction increases exponentially.
Apart from the natural objects such as asteroids, comets and meteoroids that inhabit our solar system, there are currently about 2,600 defunct satellites orbiting Earth. There are also about 10,000 objects larger than a computer screen, about 20,000 the size of an apple, and about 500,000 the size of a marble. In addition, there are about 100 million particles so small that they can’t be tracked.
As we launch more objects into space or conduct weapons tests here on Earth we create even more space debris. Having so many objects orbiting Earth presents a danger to functioning satellites and spacecraft, including the astronauts manning them. All of this space junk travels extremely fast, up to 17,500 miles per hour, which is fast enough for even small objects to cause major damage. Even tiny paint flecks can cause damage when traveling at these speeds. In fact some of the space shuttle windows have had to be replaced because of damage caused by paint flecks.
There are currently about 1,100 functioning satellites orbiting Earth. These facilitate global communication and scientific discoveries, provide us with GPS navigation and crucial weather information, and warn us of asteroids approaching Earth. Each year three to four satellites are destroyed by space junk. As the destruction continues, many of the technologies we take for granted could be endangered if the satellites that facilitate them are destroyed.
At the moment there is still a lot of space between objects orbiting Earth, so it could take a while for the collisions in space to mount up. However, there may come a time when low Earth orbit is no longer viable for satellites, and spacecraft venturing farther out in space to the Moon, Mars or beyond could be endangered.
Fortunately, NASA tracks space debris and provides guidelines on how to deal with potential collision threats in order to preserve spacecraft and ensure the safety of their crews. Depending on the nature of the threat and the amount of warning provided, the space station or other affected space vehicle may be moved slightly to avoid collision; hatches to certain parts of the station may be closed; or the crew may be moved into the Soyuz spacecraft used to transport astronauts to and from the space station. This would allow the crew to leave the station if a life-threatening collision occurs.
To limit the number of defunct satellites orbiting Earth engineers can slow them down so that they fall out of orbit and burn up in the atmosphere or they can attempt to boost them to a higher orbit, sending them farther away from Earth. There are also a number of capture and return missions being tested. One such idea involves capturing a satellite with a net and bringing it back to Earth by rocket.
If we humans want to continue to explore space and enjoy the technologies and insights our satellites provide we’re going to have to come up with creative ways to curb the space junk circling our planet.
Join the Springfield Stars Club on Tuesday, January 22nd at 7pm at the Springfield Science Museum for a talk by Paul Cardone on “The Future of Space Travel.” Cardone is an amateur astronomer and telescope maker who is active in astronomy outreach locally. Refreshments will be served, and the public is welcome. The meeting is free of charge for members, with a suggested donation of $2 per non-member.
Also, on Friday, February 1st at 7:30pm, the Stars Club and the Springfield Science Museum will host “Stars over Springfield,” an astronomy adventure for the whole family. Astronomy educator and amateur astronomer Jack Megas will present “The Winter Stars,” a guide to the winter night sky. A fee of $3 for adults and $2 for children under 18 will be charged.
Copyright © Amanda Jermyn