There's a lot of discussion these days about the best way to deal with our growing space debris problem.
No single answer will likely serve as a silver bullet, partly because the issue is a global one. Indeed, space junk experts have characterized it as a "tragedy of the commons."
Exacerbating this state of affairs is the rise of worldwide launch rates, which is driven to a significant extent by the assembly of satellite megaconstellations like SpaceX's Starlink broadband network.
Then there's the associated clutter of dead or dying spacecraft, spent rocket stages and myriad other pieces of human-made leftovers, from effluents belched out by solid rocket motors to stray nuts and bolts to paint chips to droplets bubbling out of spacecraft coolant systems, some of them radioactive. And toss in, for good measure, shards of satellites blasted apart during anti-satellite tests.
In short, it's a heavenly mess — with long-term consequences.
"With nearly 5,000 operational satellites and over 30,000 pieces of trackable debris, the ability to operate safely in space is growing increasingly challenging," Paul Bate, chief executive of the U.K. Space Agency, said in a statement last month.
For many years, multiple ideas have been put forth to clean up the space environment, including fishing-like nets, harpoons, laser blasts, de-orbiting tethers, solar sails and grappling by spacecraft outfitted with robotic arms.
However we're able to do it, "taking out the trash" in orbit would guide us toward space sustainability — the ability of all spacefaring nations to continue to use outer space for the benefit of all.
That's a lofty ambition, yes, but it's one that's addressed by the Orbital Sustainability Act of 2022 (ORBITS Act), which was introduced in the U.S. Senate on Sept. 12. The bipartisan bill seeks to "establish a demonstration program for the active remediation of orbital debris" and "require the development of uniform orbital debris standard practices in order to support a safe and sustainable orbital environment."
Then there's the U.S. Federal Communications Commission (FCC) action to shape new rules to reduce the risks caused by orbital debris, by shrinking the time that defunct satellites stay aloft. The FCC recently voted favorably to dispose of low-Earth orbit satellites within five years, not within 25 years as previously recommended to satellite operators.
"The changes being made seem to be in the right direction," said Don Kessler, a now-retired NASA senior scientist who has done pioneering orbital debris research. Indeed, the Kessler Syndrome — a feared cascade of space debris collisions that would generate ever more orbital clutter — is named after him.
"The FCC could become the regulatory agency that ensures NASA guidelines are followed," Kessler told Space.com. "Shortening the '25-year Rule' to five years would be a significant improvement, given the large number of operators of constellations in low Earth orbit who said they could easily meet a five-year rule. The FCC will need NASA's debris models to predict the outcome of any proposed changes."
Come clean on the situation
The FCC adopting a five-year rule to get things out of orbit would be "a step in the right direction," said T.S. Kelso, chief scientist and chief technical officer at CelesTrak, working from Wailuku, Maui, Hawai'i. However, he added, "it quite simply isn't enough."
"We need to change people's attitudes about the space environment," Kelso told Space.com. "While it seems a somewhat ambiguous goal, we can't really effect change without getting people to change their fundamental view of what should be done. Not how it could be done."
It is one thing to recognize that pollution of the near-Earth space environment is bad, Kelso said, but it is quite another to accept that we should change our behavior.
"Specifically, people — both in and out of the space community — should acknowledge that we should not leave things in orbit once their mission is complete," he said. "So, a rocket that is used to launch a satellite should be removed once it has delivered its payload to orbit. The same is true for a satellite that has reached its planned end of life. Get it out of orbit while it still has fuel and is controllable."
It's important to take action against space junk now, many experts say, because low Earth orbit (LEO) is only going to get more and more crowded in the future.
"The LEO constellation market is in the early stages of growth, with all indications that it will evolve into a vibrant market," said Brad King, CEO of Orbion Space Technology in Houghton, Michigan.
"The benefits of LEO constellations are now undeniable. Early entrants, such as Planet and SpaceX, have shown that it is possible to deploy large constellations and that the satellites can provide disruptive and valuable benefit to the global economy and society," King told Space.com. "Once the planet becomes accustomed to these services from space, we will incorporate them into our life, and we will come to expect them and take them for granted."
The market is now transitioning into a competitive phase, King said, in which multiple companies will look for the right business model and will learn from each other's successes and failures.
"After this phase will come consolidation, where the successful companies merge and/or absorb less successful competitors and then, finally, stabilization to a less-dynamic list of companies that will become the long-term space providers," he said.
At the moment, the biggest risks to space sustainability are orbital debris and traffic congestion, King said. "Both can lead to collisions, which amplifies the problem," he said. Orbion's propulsion systems, he added, allow each satellite to maneuver during their mission and also to safely dispose of themselves when their time is up.
Those two capabilities are important in preventing space collisions, along with knowing where space objects are and sharing that information with other operators, King said.
The cost of doing nothing
How should dying spacecraft bring themselves down? There are multiple options, each of which has costs associated with it, Kelso said.
Using a high-thrust de-orbiting method would require extra fuel and the added weight of a larger engine but would remove an object more quickly and likely in a controlled fashion, Kelso said. Using a low-thrust method, he continued, may cost less up front, but it leaves the object up longer and presents an increased risk of collision, and the ability to control where reentry occurs is diminished, increasing risk of damage on the Earth's surface.
"These risks and the potential consequences must be weighed against the up-front costs. But there is also a cost of doing nothing and, as we are beginning to understand, it will be more expensive to clean things up later than to simply prevent the problem in the first place," said Kelso. "We should have learned this by now from every other environment we have polluted."
In Kelso's view, each launch should include a disposal plan for all of the objects that it sends to orbit.
"Perhaps there is some incentive program to get satellite operators and launch providers to adhere to their plan, such as a 'security deposit' that is made prior to launch, which is fully refundable if the disposal plan is executed as planned," he said.
The bottom line for Kelso is that, just like air, land and water resources, near-Earth space is not limitless.
"Once people accept that and advocate for a commonsense approach to 'pack out' whatever we 'pack in,' getting launch providers and satellite operators to work toward that goal should just become the right thing to do," he said. "Then industry can innovate to determine how to best achieve those goals."
Leonard David is author of the book "Moon Rush: The New Space Race," published by National Geographic in May 2019. A longtime writer for Space.com, David has been reporting on the space industry for more than five decades. Follow us on Twitter @Spacedotcom or on Facebook.
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Leonard David is an award-winning space journalist who has been reporting on space activities for more than 50 years. Currently writing as Space.com's Space Insider Columnist among his other projects, Leonard has authored numerous books on space exploration, Mars missions and more, with his latest being "Moon Rush: The New Space Race" published in 2019 by National Geographic. He also wrote "Mars: Our Future on the Red Planet" released in 2016 by National Geographic. Leonard has served as a correspondent for SpaceNews, Scientific American and Aerospace America for the AIAA. He was received many awards, including the first Ordway Award for Sustained Excellence in Spaceflight History in 2015 at the AAS Wernher von Braun Memorial Symposium. You can find out Leonard's latest project at his website and on Twitter.