Pinning Tails On Satellites To Help Prevent Space Junk

Low Earth orbit was already relatively crowded when only the big players were launching satellites, but as access to space has gotten cheaper, more and more pieces of hardware have started whizzing around overhead. SpaceX alone has launched nearly 1,800 individual satellites as part of its Starlink network since 2019, and could loft as many as 40,000 more in the coming decades. They aren’t alone, either. While their ambitions might not be nearly as grand, companies such as Amazon and Samsung have announced plans to create satellite “mega-constellations” of their own in the near future.

At least on paper, there’s plenty of room for everyone. But what about when things go wrong? Should a satellite fail and become unresponsive, it’s no longer able to maneuver its way out of close calls with other objects in orbit. This is an especially troubling scenario as not everything in orbit around the Earth has the ability to move itself in the first place. Should two of these uncontrollable objects find themselves on a collision course, there’s nothing we can do on the ground but watch and hope for the best. The resulting hypervelocity impact can send shrapnel and debris flying for hundreds or even thousands of kilometers in all three dimensions, creating an extremely hazardous situation for other vehicles.

One way to mitigate the problem is to design satellites in such a way that they will quickly reenter the Earth’s atmosphere and burn up at the end of their mission. Ideally, the deorbit procedure could even activate automatically if the vehicle became unresponsive or suffered some serious malfunction. Naturally, to foster as wide adoption as possible, such a system would have to be cheap, lightweight, simple to integrate into arbitrary spacecraft designs, and as reliable as possible. A tall order, to be sure.

But perhaps not an impossible one. Boeing subsidiary Millennium Space Systems recently announced it had successfully deployed a promising deorbiting device developed by Tethers Unlimited. Known as the Terminator Tape, the compact unit is designed to rapidly slow down an orbiting satellite by increasing the amount of drag it experiences in the wispy upper atmosphere.

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Getting Rid Of All The Space Junk In Earth’s Backyard

Space, as the name suggests, is mostly empty. However, since the first satellite launch in 1957, mankind began to populate the Earth orbit with all kinds of spacecraft. On the downside, space also became more and more cluttered with trash from defunct or broken up rocket stages and satellites. Moving at speeds of nearly 30,000 km/h, even the tiniest object can pierce a hole through your spacecraft. Therefore, space junk poses a real threat for both manned and unmanned spacecraft and that is why space agencies are increasing their efforts into tracking, avoiding, and getting rid of it.
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Northrop Grumman Tests Space Tow Truck

In the early days, satellites didn’t stick around for very long. After it was launched by the Soviet Union in 1957, it only took about three months for Sputnik 1 to renter the atmosphere and burn up. But the constant drive to push ever further into space meant that soon satellites would remain in orbit for years at a time. Not that they always functioned for that long; America’s Explorer 1 remained in orbit for more than twelve years, but its batteries died after just four months.

Of course back then, nobody was too worried about that sort of thing. When you can count the number of spacecraft in Earth orbit on one hand, what does it matter if one of them stays up there for more than a decade? The chances of a collision were so low as to essentially be impossible, and if the satellite was dead and wasn’t interfering with communication to its functional peers, all the better.

The likelihood of a collision steadily increased over the years as more and more spacecraft were launched, but the cavalier approach to space stewardship continued more or less unchanged into the modern era. In fact, it might have endured a few more decades if companies like SpaceX weren’t planning on mega-constellations comprised of thousands of individual satellites. Concerned over jamming up valuable near-Earth orbits with so much “space junk”, modern satellites are increasingly being designed with automatic disposal systems that help make sure they are safely deorbited even in the event of a system failure.

That’s good news for the future, but it doesn’t help us with the current situation. Thousands of satellites are in orbit above the planet, and they’ll need to be dealt with in the coming years. The good news is that many of them are at a low enough altitude that they’ll burn up on their own eventually, and methods are being developed to speed up the process should it be necessary to hasten their demise.

Unfortunately, the situation is slightly more complex with communications satellites in geosynchronous orbits. At an altitude of 35,786 kilometers (22,236 miles), deorbiting these spacecraft simply isn’t practical. It’s actually far easier to maneuver them farther out into space where they’ll never return. But what if the satellite fails or runs out of propellant before the decision to retire it can be made?

That’s precisely the sort of scenario the Mission Extension Vehicle (MEV) was developed for, and after a historic real-world test in February, it looks like this “Space Tow Truck” might be exactly what we need to make sure invaluable geosynchronous orbits are protected in the coming decades.

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Russia’s Newest Weather Satellite May Have Been Killed By Space Junk

For humans and satellites alike, making a living in space is hard. First, there’s the problem of surviving the brief but energetic and failure-prone ride there, after which you get to alternately roast and freeze as you zip around the planet at 20 times the speed of sound. The latter fact is made all the more dangerous by the swarm of space debris, both natural and man-made, that whizzes away up there along with you, waiting to cause an accident.

One such accident has apparently led to the early demise of a Russian weather satellite. Just a few months after launch, Meteor-M 2-2 suffered a sudden orbital anomaly (link to Russian story; English translation). Analysis of the data makes it pretty clear what happened: the satellite was struck by something, and despite some ground-controller heroics which appear to have stabilized the spacecraft, the odds are that Meteor-M 2-2 will eventually succumb to its wounds.

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Humanity Creates A Cloud Of Space Garbage, Again

With the destruction of the Microsat-R reconnaissance satellite on March 27th, India became the fourth country in history to successfully hit an orbiting satellite with a surface-launched weapon. While Microsat-R was indeed a military satellite, there was no hostile intent; the spacecraft was one of India’s own, launched earlier in the year. This follows the examples of previous anti-satellite (ASAT) weapons tests performed by the United States, Russia, and China, all of which targeted domestic spacecraft.

Yet despite the long history of ASAT weapon development among space-fairing nations, India’s recent test has come under considerable scrutiny. Historically, the peak of such testing was during the 1970’s as part of the Cold War rivalry between the United States and then Soviet Union. Humanity’s utilization of space in that era was limited, and the clouds of debris created by the destruction of the target spacecraft were of limited consequence. But today, with a permanently manned outpost in low Earth orbit and rapid commercial launches, space is simply too congested to risk similar experiments. The international community has strongly condemned the recent test as irresponsible.

For their part, India believes they have the right to develop their own defensive capabilities as other nations have before them, especially in light of their increasingly active space program. Prime Minister Narendra Modi released a statement reiterating that the test was not meant to be a provocative act:

Today’s anti-satellite missile will give a new strength to the country in terms of India’s security and a vision of developed journey. I want to assure the world today that it was not directed against anybody.

India has always been against arms race in space and there has been no change in this policy. This test of today does not violate any kind of international law or treaty agreements. We want to use modern technology for the protection and welfare of 130 million [1.3 Billion] citizens of the country.

Further, the Indian Space Research Organisation (ISRO) rejects claims that the test caused any serious danger to other spacecraft. They maintain that the test was carefully orchestrated so that any debris created would renter the Earth’s atmosphere within a matter of months; an assertion that’s been met with criticism by NASA.

So was the Indian ASAT test, known as Mission Shakti, really a danger to international space interests? How does it differ from the earlier tests carried out by other countries? Perhaps most importantly, why do we seem so fascinated with blowing stuff up in space?

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Space Garbage Truck Passes Its First Test

Back in April we reported on the successful launch of the SpaceX Falcon 9 rocket to the International Space Station which carried, along with supplies and experiments for the orbiting outpost, the RemoveDEBRIS spacecraft. Developed by the University of Surrey, RemoveDEBRIS was designed as the world’s first practical demonstration of what’s known as Active Debris Removal (ADR) technology. It included not only a number of different technologies for ensnaring nearby objects, it even brought along deployable targets to use them on.

Orbital debris (often referred to simply as “space junk”) is a serious threat to all space-faring nations, and has become even more pressing of a concern as the cost of orbital launches have dropped precipitously over the last few years, accelerating number and frequency of new objects entering orbit. The results of these first of their kind tests have therefore been hotly anticipated, as the technology to actively remove debris from Low Earth orbit (LEO) is seen by many in the industry to be a key element of expanding access to space for commercial purposes.

Six months after its arrival in space we’ve now starting to see the first results of the groundbreaking tests performed by the RemoveDEBRIS spacecraft, and so far it’s very promising.

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Space Garbage Truck Takes Out The Trash

On April 2nd, 2018 a Falcon 9 rocketed skywards towards the International Space Station. The launch itself went off without a hitch, and the Dragon spacecraft delivered its payload of supplies and spare parts. But alongside the usual deliveries, CRS-14 brought a particularly interesting experiment to the International Space Station.

Developed by the University of Surrey, RemoveDEBRIS is a demonstration mission that aims to test a number of techniques for tackling the increasingly serious problem of “space junk”. Earth orbit is filled with old spacecraft and bits of various man-made hardware that have turned some areas of space into a literal minefield. While there have been plenty of ideas floated as to how to handle this growing issue, RemoveDEBRIS will be testing some of these methods under real-world conditions.

The RemoveDEBRIS spacecraft will do this by launching two CubeSats as test targets, which it will then (hopefully) eliminate in a practical demonstration of what’s known as Active Debris Removal (ADR) technology. If successful, these techniques could eventually become standard operating procedure on future missions.

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