The European GOCE spacecraft will use electric engines to provide critical thrust needed to keep it from toppling out of orbit and plunging to Earth.
Those T5 ion thrusters are performing well after GOCE launched March 17, from Russia, according to QinetiQ, designer and builder of the craft.
GOCE is a European Space Agency (ESA) asset that measures gravitational pull of the Earth in precise measurements, skimming just above the atmosphere.
Because the atmosphere place a slight drag on GOCE, it requires the ion engines to help it maintain the velocity and altitude required to remain in orbit.
The strength of the Earth’s gravitational field diminishes with altitude, so GOCE’s orbit skirts the outer reaches of the atmosphere at just 260-280 kms (160-175 miles) above the Earth. As a result the spacecraft experiences small but significant disturbances in its motion from atmospheric drag. QinetiQ’s electric engines act as cruise control for the spacecraft, providing tiny but continuous levels of thrust to compensate for atmospheric drag without disturbing the sensitive science payload – quite literally preventing the spacecraft from falling out of the sky.
ESA mission manager Rune Flobererghagen said that all systems on the spacecraft had now been activated and the mission will become fully operational in the next few weeks. “Now we must learn to drive our super-satellite,” he said.
The full commissioning proved that the main and back-up engine chains are performing precisely to specification across the full thrust range, providing very stable thrust with no interruptions and a perfect thrust vector.
QinetiQ’s engines, known as T5 ion thrusters, are about ten times more efficient than rocket thrusters that traditionally have propelled spacecraft, requiring only 40kgs of xenon propellant for the entire 30-month GOCE mission.
In the next few years electric propulsion could make previously impossible missions into deep space a reality and extend the operational life of commercial communications satellites, reducing costs.
QinetiQ is working with partners to qualify its T6 thruster, an even more advanced electric propulsion system that has been designed for use on the next generation of deep space and interplanetary science missions, such as the ESA BepiColombo mission to the planet Mercury.