Ideas in Motion

The World’s Biggest Junkyard: The Atmosphere

Jul 9, 2021 12:04:08 PM

The atmosphere is becoming cluttered with space debris at an alarming rate. Decades of astronauts dumping garbage into the atmosphere in orbit, as well as defunct satellites from many countries and, now, private companies, threaten future development in our atmosphere. Here we take a look at plans that might be in place, or planned, to remove human-made space debris. Further, we seek to understand the risk of an accident in the atmosphere such as a collision of defunct satellites with viable ones, and what a cleanup might look like. Space debris is an essential part of space exploration, yet few articles address the consequences of accumulating “space junk.”

At first glance the solution might seem obvious. Earth’s gravity will pull the debris toward its surface, causing friction and disintegration of the floating nuisances. The glitch in that logic, however, is that space exploration has expanded beyond the atmosphere to space beyond the reach of our planet’s gravitational pull.  A few space agencies have realized the impact of the accumulating space debris and have begun work to reduce/eliminate the amount of debris the world creates. Currently, there are 6,000 satellites circling Earth. 60% of those are defunct, and 40% operational.

SpaceX is one newcomer to space exploration that is dedicated to doing something to alleviate the problem. With the support and assistance of NASA, SpaceX launched four astronauts into space on Friday, April 23, bound for the International Space Station (“ISS”) using a recycled rocket and capsule known as the Dragon capsule (SpaceX first used the Dragon capsule on a mission in May 2020). This mission is the third crew flight in less than a year for Elon Musk’s rapidly expanding company. The crew reached the International Space Station the following morning. They will spend six months at the orbiting lab. Dragon will carry the current crew back to Earth on April 28 after its six-month stay. In fact, earlier this month, NASA awarded SpaceX a nearly $3 billion contract to provide a fully reusable lunar lander that will transport astronauts to the surface of the moon, which will be a “test case” for Musk’s ‘Starship.” The Starship will carry astronauts to Mars with the intent of building a city there.

During the recent launch by SpaceX, NASA advised the crew to put on their spacesuits in case of a collision with a piece of debris. Fortunately, the advanced notice allowed the crew to adjust its trajectory to avoid the collision. As we might imagine, the ISS is not immune to collision with space debris. A Russian and American team of experts had to carry out an avoidance maneuver in 2020 to change the orbit of the station to avoid collision with space trash.

Besides developing recyclable rockets and crew compartments, experts have been thinking about possible solutions to this problem for several years. Several proposals seem viable. One is to use high-powered giant lasers to slow down the debris enough to cause reentry the atmosphere and burn up. The use of giant space balloons filled with gas attached to the debris could cause enough drag to force reentry. Another is to use self-destructing “janitor satellites” that could seek out and attach to the debris. The explosion would force reentry. Rockets full of water might cause reentry when they release their payload to cause a wall of water debris would bump into to slow down.

One company is developing space pods that could knock debris out of orbit. The developers claim that the pods could clean up space debris in about 10 years. Tungsten dust in sufficient quantity, and put into low earth orbit on a trajectory opposite that of the targeted space junk, would be enough to slow smaller space debris down to cause reentry. There is a health concern with this solution, however. Exposure to tungsten dust has been lined to stillbirths and abnormal musculoskeletal development.

The US Defense Advanced Research Project Agency (“DARPA”) is considering funding the development of a space “garbage truck” that would carry 200 giant nets that could be extended out to scoop up space garbage.  DARPA is exploring satellite recycling where existing inoperable satellites could be mined for parts. Lastly, Altius Space Machines is developing a magnetized robotic arm to attach to any space object for disposal.

Most of these solutions focus on getting the debris to reenter the atmosphere where what is left of the objects after reentry falls into an ocean that are full of debris already. We need a viable solution that cleans up the debris in an environmentally sound way.

 

Bill Link

Written by Bill Link