A Space Debris Sensor will be installed to International Space Station.
Nearly 30 satellites are being launched into space this year, with 14 of them coming from the U.S. As if that does not sound crowded enough, they will be joining one of the most congested regions in space, the geostationary orbital ring.
This orbital ring is the only space where objects move synchronously with earth, making it ideal for satellites and thus, one of the most frequented regions in space. This has also lead space debris to become a more pressing issue than ever before, with scientists reporting around 750,000 objects larger than a centimeter, and 166 million objects larger than 1 millimeter currently reside in Earth’s orbit.
The Space Debris Problem
Defunct spacecraft and satellites left in orbit can drift and endanger other objects in their vicinity. Experts have recommended retiring the defunct objects to what they call a “graveyard orbit” located just 186 miles overhead. While this solution has worked thus far, there is no guarantee it will remain that way.
Aging satellites are known to slowly break apart, which can pose a threat considering the pieces carry residual energy. Upon colliding with other objects, these pieces can explode. The fragments produced from these collisions can be thrown back toward the geostationary ring’s orbit.
An example of this happened in 2009 when the deactivated Kosmos 2251 crashed into the operational Iridium 33 and created a cloud of debris that now makes up a large portion of the low earth orbit space debris. It’s essential that this threat be prevented by addressing the need to clean up non-functioning satellites.
Combating Space Debris
The ESA reports that one of the steps to addressing this issue needs to be in the form of monitoring the environment while satellites and space crafts are still active. NASA is taking comparative measures with their Space Debris Sensor (SDS) which will be installed on the International Space Station (ISS) and will spend the next two to three years monitoring space debris to learn about its characteristics, wrote David Szondy.
“The orbital debris environment is constantly changing and needs to be continually monitored, while the upper atmosphere causes debris in low orbits to decay, new launches, and new events in space will add to the population,” said Joseph Hamilton.
Astronauts will mount the SDS on the exterior of the Columbus module, providing near-real-time impact detection through a three-layered acoustic system. The system is designed to collect data from particles on impact, allowing scientists to determine debris particle size, density, and velocity.
“The backstop has sensors to measure how hard it is hit to estimate the kinetic energy of the impacting object,” says Hamilton. “By combining this with velocity and size measurements from the first two layers, we hope to calculate the density of the object.”
Space Debris Mitigation
It is of great interest and urgency that space debris be mitigated considering it has the potential to damage thermal protection systems, spacesuits, windows, and unshielded sensitive equipment.
According to Szondy, the amount of space debris in orbit remains constant due to debris entering the atmosphere at a rate of between one and three objects a day. At the moment, one of the best solutions available is that we stop sending debris at all. This would, at the very least, prevent the amount of debris in orbit.
While there is no international treaty governing the control of debris, it’s important that we continue to regulate traffic similar to the way we do at sea and in the air to avoid collisions with the space debris still in orbit, at least until the SDS allows us to better understand how to go about cleaning up all the debris.