In the race to commercialize space, one premise is undisputed: It’s getting crowded up there.
From private enterprise to universities to the military, everyone has their eye on the sky as it comes financially within reach. Yet it’s not clear how all these new orbital gadgets will coexist, zipping around at 17,000 miles per hour, surrounded by a high-speed minefield of debris from mankind’s earlier space ventures.
Aerospace Corp., a federally funded research center, has a proposal to remedy this congestion: Stick a small, 100-gram GPS transponder on each craft that’s launched, for tracking, identification and oversight—even after the satellite stops working. Common in the civil aviation and maritime industries, transponders have never made it widely to space. Current satellite tracking consists mostly of ground-based radar and optical tracking telescopes.
Humans have launched some 7,500 satellites since the dawn of the Space Age, with more than 1,500 still in working order. That’s a fraction of the more than 20,000 new vehicles envisioned by a range of space companies such as Planet Labs Inc., OneWeb, LeoSat Enterprises Inc. and Elon Musk’s SpaceX.
Defunct satellites often burn up in Earth’s atmosphere, while some larger craft are sent to their doom in a remote area of the South Pacific. Still others are flown farther into space, to an orbital “graveyard” far beyond where working satellites roam.
Yet, in many cases, the spent vehicle (or pieces of it) becomes hypersonic space flotsam, menacing other satellites with the possibility of instant destruction. Add to this bits of blown up spacecraft or discarded parts, and the risk of sudden demise for any multimillion dollar spaceccraft begins to rise. And the bonus from each new collision? Additional debris (though some are ).
Today, satellite operators must manage these potential disasters (NASA calls them “conjunctions”) every month or two. Soon they will become daily routine, said Andrew Abraham, a senior researcher and engineer at Aerospace.
The U.S. Joint Space Operations Center tracks about . The agency issued 1.2 million collision warnings in 2016, said retired Navy Admiral Cecil Haney, an Aerospace senior adviser and former head of U.S. Strategic Command. Operators made 148 avoidance maneuvers, which involves firing thrusters to get out of the way. Generally, the warnings come about five days to seven days before a potential collision, Haney said.
“These operators don’t want to move their satellites just on a whim,” given the finite fuel on-board, he said on April 18 during a panel discussion at the Space Symposium in Colorado Springs, Colorado. When it comes to managing all the objects up in space, and those yet to come, Haney warned: “It really is something we have to get at—and, in my mind, get at quickly.”
The transponder, including a GPS module and radio transmitter, is the size of a deck of playing cards, Abraham said. The Aerospace idea would be for it to report a craft’s location on a regular basis, allowing trackers to narrow its position at any time to tens of meters. The system would operate in three modes: Normal, thrust (for when the satellite is repositioning itself) and debris. The last mode would be a low-power setting that would report less frequently but for as long as 40 years, thanks to a small solar cell.
Such devices would incur additional costs, they wouldn’t solve the problem of what’s already up there and it’s not clear who would coordinate all the data they would provide. A government agency, industry consortium or a new commercial or nonprofit organization? Perhaps “volunteer satellite watchers,” who would share the data on a public website? Aerospace sees advantages and drawbacks to each, but notes that—based on the maritime industry’s approach—an international body may be best. And the benefits may far outweigh expense, especially if GPS tracking can reduce orbital maneuvers and extend satellite life spans. (Some large satellite operators use GPS on their crafts.)
One catastrophic “conjunction,” such as the February 2009 collision of a U.S. communications satellite with a dead Russian satellite, can mean disaster, not only for the company involved but for operators of other satellites. New debris increases uncertainty and requires quick assessment to determine who needs to move their craft out of the way—and how fast. The 2009 accident, coupled with China’s deliberate destruction of a weather satellite two years earlier, account for more than one-third of all the debris in low-Earth orbit, according to a 2011 NASA study.
Beyond debris, a further hassle for satellite operators could be addressed by these tracking devices: gravity. Depending on their mass, size, shape, orientation and type of orbit, satellites can slowly go where they’re not supposed to be. Over a few days, the position of a craft in low-Earth orbit can change by tens of kilometers, making it difficult to keep close tabs on its precise location. Over weeks, it’s easy to “lose” an orbiting object altogether.
The first decades of human spacefaring “relied upon the ‘big sky’ approach to avoiding orbital crashes,” Abraham writes. “The assumption was that the volume of space is too large compared with the volume occupied by manmade objects” for a crash to happen, except very rarely, he said. That approach, however, is quickly becoming dated as more objects are hurled into space and use specific orbital slots, instead of being distributed around the planet more evenly.
Space-traffic management has little government oversight now, although the Trump administration has proposed that the U.S. Commerce Department assume these duties and coordinate with other nations. Greg Wyler, founder of the internet satellite company OneWeb, even suggested that civil aviation rules for aircraft spacing could be applied to satellite management.
Either way, writes Abraham, “The forecasted increase in launch rates eliminates the status quo as a viable option.”
To contact the author of this story: Justin Bachman in Dallas at jbachman2@bloomberg.net
To contact the editor responsible for this story: David Rovella at drovella@bloomberg.net
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