In 1978, Donald Kessler, a NASA scientist, contested the large sky notion. In a study titled “Collision Frequency of Artificial Satellites: The Creation of a Debris Belt,” Kessler presented the case that there was a serious concern about the growing number of artificial objects in space. Kessler noted that it wasn’t simply these things’ sluggish growth but also how inescapable encounters would produce a cascading effect. The number of objects in space might grow exponentially in the event of a large collision, producing thousands of fragments of debris that could strike other objects. This event would result in a “growing belt of debris,” which would subsequently be named the “Kessler Syndrome.”

Significant repercussions would result from the formation of this “belt of debris,” starting with harm to already-existing satellites as more and more are struck by projectiles moving at high speeds. This might someday interfere with communication and weather observation satellites, which would have a significant effect on Earth’s population. Worse still, any upcoming space exploration flights would become more riskier, including service missions to fix already-existing spacecraft in orbit.

The Orbital Debris Program Office of NASA is now keeping an eye on over 19,000 space debris objects that are larger than 10 cm. These are the largest objects, thus Earth is most at risk from them. This danger consists of the object surviving re-entry into Earth and inflicting damage here, colliding with another piece of debris and producing the Kessler-foreseen effect, or hitting a spacecraft or the International Space Station.

Regretfully, there are also nearly incalculable (estimated at over 10 million) things that are smaller than a centimeter, and 500,000 items that are between one and ten centimeters. Furthermore, the risk does not only come from large pieces; the International Space Station (ISS) is thought to be susceptible to being struck by items as small as one centimeter in diameter. The International Space Station (ISS) was shrewdly constructed to be able to steer clear of approaching debris, and in the last thirty months alone, it has had to perform five such moves. These pieces of debris, according to NASA officials, are the biggest danger to the ISS. In 1978, Kessler prophesied that within 30 to 40 years, debris collisions would start to cascade. And just in time, we are now beginning to see evidence. The first incident occurred in 2007, and Kessler was not prepared for it at all. It was likely a military show of force when China fired a missile at one of its retired satellites. About 3000 bits of debris were formed when the rocket struck its target, and these are currently hurtling across space and triggering other collisions. A sizable piece nearly struck the Hubble Space Telescope and the space shuttle Atlantis. The second incident was more consistent with Kessler’s initial contention that space would only get denser until collisions were unavoidable. Iridium 33, a U.S. communications satellite, was struck on February 10, 2009, by Cosmos 2251, a Russian out-of-service satellite. When they collided, hundreds of tiny fragments formed a “cloud of debris” at a speed of 18,000 miles per hour.

The quantity of debris in orbit around the Earth significantly increased as a result of this collision and the Chinese rocket. According to Kessler, these two incidents alone “wiped out what we had done in the last 25 years” in terms of mitigating the threat posed by space pollution and “doubled the number of fragments in Earth orbit.” Kessler’s efforts resulted in a set of regulations and guidelines defining what kinds of things might be left in space, which were later embraced by numerous other countries.

NASA and the US military started to take space pollution far more seriously after the 2009 satellite collision. Iridium 33 wasn’t even on the radar of these agencies, which had previously been monitoring just 120 satellites for possible collisions. They soon increased their capability, and at this point, they kept an eye on tens of thousands of debris bits and thousands of satellites.

The Conference on Orbital Debris Removal, which Kessler and his associates hosted in December 2009, aimed to find a wide range of innovations and ideas for clearing the contaminated space surrounding our planet. “I’ve gone from being skeptical to thinking maybe something will work,” said Kessler’s admiration for the outcomes. Things can be brought down, but it will be expensive. NASA is currently exploring several options, and funding for research grants in this field was included in the agency’s 2011 budget plan.

Many other clean-up techniques have been proposed, all of which are still in the R&D stages. Having said that, the following are some of the most intriguing concepts:

1.       Plans have been released by DARPA, the Defense Advanced Research Projects Agency, for an Electrodynamic Debris Eliminator with 200 nets connected to a central unit. Recycled materials or even transported back toward Earth to burn up in the atmosphere might be made from debris caught in the nets. 2013 will see test flights conducted by DARPA.

2.       The British-designed CubeSail is based on sail technology that moves by harnessing solar energy. The project team plans to use a sail attachment for future satellites to maneuver the item either out into space or away from the “debris belt” and toward Earth shortly. In the future, they want to develop unique debris cleaners that can gather items in space by navigating with solar sails.

3.       A vehicle dubbed “Rustler” was proposed by the Seattle-based space corporation Tethers Unlimited to attach a wire mesh attachment spanning miles to space junk. If one were to send an electrical current through the attachment, the object would be drawn in by Earth’s magnetic field and finally burn up in the atmosphere based on the laws of electromagnetic forces.

Georgios Ardavanis – 02/11/2023