Space: engine fuelled by air will enable low-flying class of satellites

The European Space Agency (ESA) has test-fired an engine that opens the path for a novel class of low-flying Earth-orbiting space missions. Called an air-breathing electric thruster, it is designed to work at the top of the Earth’s atmosphere. It sucks in the scarce air molecules and uses them as propellant. Low-flying satellites, those in orbits of about 200-300km altitude, are gradually pulled out of orbit by the drag of the residual atmosphere.

For example, ESA’s GOCE mission operated in this region of space. It flew for five years thanks to an electric thruster that used xenon fuel to counteract the atmospheric drag. When the 40kg of xenon ran out, however, the spacecraft fell to Earth and burned up in the atmosphere.

The new thruster, designed by an ESA-led team that includes Sitael in Italy and QuinteScience in Poland, does not carry xenon. Instead, it sucks in the scarce air molecules that cause the drag, and uses them instead.

The successful test firing took place in a chamber that simulates atmospheric conditions at 200km altitude. Further development is expected to lead to a whole new class of low-flying satellites that could operate indefinitely.

(THE GUARDIAN)