ESA, with the raddest space news we’ve had in a while:
In a world-first, an ESA-led team has built and fired an electric thruster to ingest scarce air molecules from the top of the atmosphere for propellant, opening the way to satellites flying in very low orbits for years on end.
ESA’s GOCE gravity-mapper flew as low as 250 km for more than five years thanks to an electric thruster that continuously compensated for air drag. However, its working life was limited by the 40 kg of xenon it carried as propellant – once that was exhausted, the mission was over.
Replacing onboard propellant with atmospheric molecules would create a new class of satellites able to operate in very low orbits for long periods.
This could be huge for very low orbit satellites—something that has been rumored to be used by SpaceX’s second generation internet constellation to massively improve latency.
But there are some other interesting uses you can come up with, if you keep reading the details here:
Air-breathing electric thrusters could also be used at the outer fringes of atmospheres of other planets, drawing on the carbon dioxide of Mars, for instance.
There are no valves or complex parts – everything works on a simple, passive basis. All that is needed is power to the coils and electrodes, creating an extremely robust drag-compensation system.
The challenge was to design a new type of intake to collect the air molecules so that instead of simply bouncing away they are collected and compressed.
If the air molecules can be collected, compressed, and stored, you could imagine an imaging or communications satellite in orbit around Mars that occasionally drops its periapsis into the atmosphere to refuel, and once refueled, boosts its periapsis back to its operational altitude.