ESA Looks to Reduce Debris Threat From Batteries

So far, about 200 explosions and at least 5 collisions in space have occurred. Further explosions and collisions are very likely. The explosions are mainly caused by on board energy sources, either due to pressure build-up in propellant tanks, battery explosions, or the ignition of hypergolic fuels. (Credit: ESA)
So far, about 200 explosions and at least 5 collisions in space have occurred. Further explosions and collisions are very likely. The explosions are mainly caused by on board energy sources, either due to pressure build-up in propellant tanks, battery explosions, or the ignition of hypergolic fuels. (Credit: ESA)

PARIS (ESA PR) — Across a satellite’s working life, batteries keep the craft’s heart beating whenever it leaves sunlight. But after its mission ends, those same batteries may threaten catastrophe.

Space debris mitigation rules require the complete deactivation of electrical power sources aboard a satellite on retirement, in order to guard against explosive accidents that might produce fresh debris dangerous to other satellites.

Now a new study by ESA’s Clean Space initiative – tasked with reducing the space industry’s environmental impacts on both Earth and space – aims to evaluate battery behaviour after a satellite shuts down, assessing the risk of breakup and ensuring full ‘passivation’.

Batteries are among a satellite’s bulkier items of equipment. Typically, they feed their host with power during launch. Once in orbit, it switches to power from its solar arrays, but the battery is an important backup to store power for eclipses and emergencies.

To reach the high reliability and performance a satellite demands, extending across many months or years, batteries are carefully designed and extensively tested in advance of launch.

By contrast, their behaviour after their parent mission has been shut down remains a relative blind spot.

As a satellite drifts freely, could batteries endure the harsh environment of orbit – including wild temperature swings, degradation of thermal control and components as well as radiation exposure – without leakage or bursting?

Some past satellite breakups have been triggered by battery malfunctions, although mostly before the 1990s and involving older non-lithium designs.

This multidisciplinary study aims to ensure a fully inert power system at the end of a mission, perhaps through physical disconnection, while also preventing accidental premature passivation.

Bidders are welcome on this contract. For more information check the invitation package, accessible via ESA’s tendering system.

  • windbourne

    I am surprised that Boeing or others have developed a sat system in which there is a separate tug that plugs in once it is in orbit. It would make sense to have a multiple units can plug on to any sat and provide thrust, orientation, electricity, even extra CPU and memory.
    With such an approach it would make it possible to quickly change parts out.

  • Hug Doug

    It would be just as cheap and easy to replace the satellite entirely rather than just “send up a tug” to an existing satellite. so why not have an entirely new satellite rather than revamp an old one? then you don’t need to worry about sending up something that might crash into the satellite or be unable to link up to it correctly, etc. and it is much simpler. fewer links in the chain to fail.

  • windbourne

    Correct me if I am wrong, but we have plenty of sats that work, except that they no longer have fuel?
    For example, the weather sats come quickly to mind.
    If we can CHEAPLY replace the tug unit, and allow the rest to continue to work, then it would be a great deal cheaper, AND quicker to replace.
    Likewise, it would be useful to be able to switch a number of sats from using chemical engines over to electrical engines, would it not?
    And if only that transportation unit is replaced, it would lower the amount of launch costs to put it into orbit.

    The last thought is that by having a transportation unit that is produced in high volumes would lower the costs for all future sats.
    For example, see SpaceX’s approach to rockets.

  • Hug Doug

    satellites that work but have run out of fuel? there might be some, but none that i know of offhand.

    operational lifespan is usually about 10 years or so, for a typical satellite, by then either its the hardware is hopelessly obsolete, or either the batteries or the solar panels have degraded to the point of uselessness, or perhaps out of maneuvering fuel… or more typically, a combination of the above. then they’re usually boosted to a graveyard orbit and shut down. once they’re shut down, you usually can’t turn them back on, because they drift in their graveyard orbit and don’t keep station to the sun or Earth, so the battery drains and the electronics fail and the antennas that receive signals aren’t pointed at the Earth.

    i’m not sure how useful it would be to switch from chemical thrusters (i assume you mean hydrazine) to electric thrusters (i assume you mean an ion engine / hall effect thruster) both require fuel, both would run out of fuel eventually. and just because you can maneuver doesn’t mean the satellite is capable of performing the functions it needs to. hardware goes obsolete. many of the communications satellites being launched today are to replace obsolete ones that are incapable of transmitting either the bandwidth or the wavelengths that are needed.

  • windbourne
  • Hug Doug

    That’s great, but it doesn’t mean that they’re not obsolete. it doesn’t mean they can transmit in the bands or the quantity of data that needs to be transmitted.

    GOCE was something else entirely. few satellites orbit at the altitude it did.

  • Geoff T

    Not only that, but even if a tug can act to replace any dead systems, provide refueling or provide attitude control there’s no guarantee that completely different systems may not fail at any second. Satellites simply fail in rather unpredictable ways and so dedicating resources to extend the lives of some satellites might be a false economy.

  • Hug Doug

    that’s a very good point.