European experimental space junk removal mission to launch

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The competition heats up: A European Space Agency mission to test technologies for removing space junk will launch sometime next year.

Presented at the Royal Society’s summer science exhibition this week, and led by the Surrey Space Centre, the systems included a net, harpoon and drag sail, which scientists have incorporated into a test platform for launch into space. The platform will also carry “artificial junk” in the form of small satellites known as CubeSats.

Once the platform is launched into space, a CubeSat will be released. “The CubeSat will be ejected from the platform and then we’ll fire the net at it,” said Forshaw. The CubeSat, hopefully encased in the net, will then fall back towards Earth and burn up. In the case of the harpoon, the researchers have attached a target made of spacecraft material to a carbon-fibre boom that extends from the platform. “When the harpoon impacts it, it is actually going to simulate a real spacecraft being hit,” said Forshaw.

At the end of the mission the third system, a drag sail will be deployed. Attached to the platform, the sail will speed up its return to Earth where it will burn up in the atmosphere. Similar systems have been proposed for future satellites to allow them to be disposed of without leaving space junk.

With the Chinese, NASA, and private companies all developing robotic missions to either clean up space junk or repair satellites, the competition to do this work is going to get very intense in the next decade.


  • LocalFluff

    Competition for what, who pays?
    Hunting cubesats with harpoon and net sounds like a scuba diving hobby. Students with a budget, sigh. This will lead to nothing. Space is often just used as a motivator for students to do their homework. “Now it is play hour, today we play science fiction in space.” The space age is not being taken seriously.

    What should be done is to bring down the heavy dead satellites to decrease the potential space junk mass. And to somehow require that all satellites are designed to deorbit themselves at end of mission. I do not think it requires any world governement regulation or strange space law. People don’t pee publically on the streets, leaving space junk behind is as embarrising.

  • Edward

    There are already suggestions in place that low Earth orbiting satellites be placed in orbits that decay and reenter within 25 years. Geostationary satellites are designed to climb into a higher “graveyard” orbit at the ends of their lives. There are efforts to prevent space debris from being a problem, but there is no enforcement for any satellite maker, launcher, or operator for not following these suggestions.

    As for the satellite that you think is a student play toy, the net and harpoon ideas are intended to be used in the future to deorbit any unused/dead satellites that will not deorbit themselves. The article did not present this very well. For an operational space-debris mission, sometime in the future, once a target satellite is captured by the shooting satellite, the latter can place the former into an orbit that will decay rapidly. The intention is to reduce the amount of dead satellites, and thus reduce the chances for future collisions.

    I would hope that someday, much of the orbital debris will be reused by space manufacturers, reducing the cost of lifting manufacturing material into orbit. Similar capture methods would be useful for that, too.

    The space age *is* being taken seriously, and these guys are leading the charge. As far as I know, they are the only ones actually performing flight tests on their ideas for debris mitigation.

  • wodun

    the systems included a net, harpoon and drag sail,

    A harpoon with a drag sail or two separate devices, a harpoon and a drag sail? You can pry the Oxford comma from my cold dead typewriter.

  • wodun

    Some countries don’t want the graveyard orbit cleaned because that is where they hide their ASAT or other weapons.

  • Localfluff

    I always appreciate your very informed comments. Even when I do not agree I still learn something. Especially then. Now, whoever is leading the charge after smallsats with harpoons and nets I bet will not accomplish anything useful. Maybe those guys have a great idea which I misrepresent, I just hit on the headlines here.

    First thing to do about space debris in LEO is to take down the big satellites. A handful of missions could do that. They will fragment sooner or later. The small stuff seems just hopeless to deal with. I think it can only be prevented and not cleaned up.

    I am so old school while paradigms are shifting. Maybe it will soon be trivial to keep track of every debris, zapping the small ones with a laser and navigating away from the bigger ones, and fly safely in LEO. Driving a car means meeting unknown crazy people driving a ton heavy car at a hundred kilometer per hour towards you just a couple of meters to your left. NASA would never have approved of that concept. Still, it works quite well.

  • Dick Eagleson

    People don’t pee publically on the streets, leaving space junk behind is as embarrising.

    You’ve obviously never visited a major American city. Or a major Italian one, for that matter.

  • Edward

    You wrote: “First thing to do about space debris in LEO is to take down the big satellites.”

    I agree. The small stuff is difficult to eliminate. It is not easily tracked (meaning it is not tracked at all), and is difficult to capture. The net and harpoon ideas described in the article are intended to be used to take down the big satellites, but RemoveDebris uses a 2-unit or 3-unit cubesat in order to test the concept. If the net cannot be made to work on a cubesat, then it is not worth trying a version to capture big satellites. Same for the harpoon idea.

    RemoveDebris is most likely attempting to see whether they create more debris than it is worth when capturing a big satellite with a harpoon. It also will test a “drag-sail,” when the other experiments are completed, to increase atmospheric drag and quicken the satellite’s own deorbital demise.

    There are other ideas for capturing or otherwise deorbiting satellites, but these three methods seem to be the first to be tested, and they have included a test of a LIDAR targeting system. At least someone is starting to *do* something about the problem. The space community has talked about it for decades, there are a few patented ideas for doing something*, and someone even made a movie, “Gravity,” to bring the general public’s attention to the issue (over-dramatized and showed space being made unsafe for human travel in the course of a single day, but unchecked, debris could have the same effect, in a few decades).

    The good news about the small debris (paint chips, etc.) is that in LEO, the area to mass ratio is generally large, compared to whole satellites, so it falls out of orbit relatively quickly — but that can still be months, years, or decades, depending upon altitude.

    An advantage to dedicated launchers for small satellites, an industry that is just about to start up, is that small satellites can be placed into LEO, rather than a Geostationary Transfer Orbit, as happens with some of today’s secondary-payload cubesats. Most cubesats and small satellites tend to have relatively short mission duration, so putting them in higher, long-lived orbits is unnecessary.

    * My favorite, patent US20070285304 (Gas-Blast), or as I like to call it, Leaf Blower, puffs some gas at a satellite to slow its orbital speed. Satellite capture is not needed for this one.

    Patent US6830222 uses a balloon in the same way that RemoveDebris uses a drag sail to increase atmospheric drag. Satellite capture is necessary for this one, or the balloon can be a built-in mechanism, such as the drag sail on the RemoveDebris satellite.

    There are several other patents with other ideas, but these two should give you an inkling of what else is being thought of to solve the orbital debris problem. Slowing a LEO satellite by 0.25 km/second (out of 8 km/sec orbital speed) is enough for it to travel deep into the atmosphere, causing immediate or eventual reentry, breakup, and burn-up. Ideas for more controlled reenty can make sure that satellites reenter over the Pacific Ocean, where there is little land or few ships for any surviving debris to hit.

    Here is a simulation to visualize the reentry of the Upper Atmospheric Research Satellite (UARS) in 2011, 20 years after launch. NASA expected a couple of dozen pieces of UARS to survive reentry.

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