MORGANTOWN, W.Va. (WBOY) — What if you woke up one day only to find out you couldn’t get the day’s weather forecast or get a signal on your TV? Well, WVU recently started a new research team to make sure you don’t have to find out.
With a dramatic increase in space missions over the past 10 years, Earth’s orbit is accruing more and more debris or “space junk” that can pose serious risks to GPS and communication satellites. Space junk can vary greatly in size, ranging from entire satellites that are no longer in use to tiny pieces of metal only millimeters across.
A majority of space debris resides in low earth orbit—at or below 1,200 miles (2,000 km) above the earth’s surface. At that altitude, debris orbits the earth at about four to five miles a second; at that speed, a gallon of milk (8.5 lbs) carries about as much force as a car moving at 60 mph.
The Department of Defense is actively tracking about 27,000 pieces of space junk, but many, many more pieces of debris are too small to be detected. NASA estimates about half a million objects in Earth’s orbit that are marble-sized (about one centimeter) or larger, and more than 100 million pieces that are one millimeter or larger. It sounds like a lot, but if it’s not causing problems, then why are organizations like NASA, the European Space Agency (ESA), and now WVU, collectively investing millions of dollars to track space garbage?
The answer is a phenomenon called “Kessler syndrome.” Kessler syndrome is like a line of dominos in space, only much more catastrophic. It’s a theoretical limit that when reached, there will be so much junk in orbit that we will be unable to launch new satellites or spacecraft from Earth. Debris would hit satellites, which would create more debris, which would damage more satellites, creating a cascading effect that would essentially “landlock” Earth from the rest of space for years, decades or even centuries depending on where the debris is located.
If any piece of debris hit a satellite in the wrong spot, it could be mission-ending, but their high speed and tiny size make them impossible to track. That’s the problem Dr. Piyush Mehta and his team at WVU are looking to solve.
Mehta said that it all boils down to the size of the object and distance. An object three centimeters wide could be tracked in low earth orbit, but impossible to track in higher orbits. This picture shows a large concentration of objects in low Earth orbit and fewer objects the farther you get from Earth. That doesn’t necessarily mean there are fewer objects the farther away you get, it just means we can’t see them; and it’s the objects we can’t see that pose the greatest risks.
According to Mehta, the two most common ways to detect space debris are ground-based radars and ground-based optical sensors, like lasers or telescopes. One of Mehta’s ideas for detecting small space debris is by conducting research alongside WVU’s new Center for KINETIC Plasma Physics to see how debris interacts with its surrounding plasma environment. By using that information, they may be able to learn better ways of detecting debris. However, detecting debris is only half the battle. The other half is avoiding a potential collision, either by moving a satellite or spacecraft in danger of being hit or by moving the piece of debris itself.
“For example, one of the examples is a ground-based laser system,” Mehta said. “So if you were to determine that the two objects are on the path to collision, but neither of them have the capability to maneuver, you could point a laser at one of these objects and move them.”
The European Space Agency (ESA) is already developing a similar method with its IZN Laser Ranging Station in Spain. Although it can’t move debris directly, it uses high-powered laser light to precisely measure the orbits of satellites to calculate the chance of a collision.
“I have dedicated a significant amount of my career and life to this problem,” Mehta said. “I do want to point out that this is an extremely difficult and challenging problem, but I believe we have a good platform, the right team, the right technical expertise and the right approaches to make good progress toward and do our best at tackling this challenge.”
Out of the four groups that received funding for solving this issue, Mehta’s team is the only university-led program. Undoubtedly, it is a problem space agencies will need to solve if we wish to continue launching new and exciting missions to space, like NASA’s planned Artemis V mission, which aims to put humans back on the moon for the first time in over 50 years.