2023-11-23 12:42:45
MADRID, 23 Nov. (EUROPA PRESS) –
ESA’s CryoSat satellite has switched to its reserve propulsion system after a fuel leak threatened to end the mission in 2025.
The exchange, carried out on November 21, has the potential to extend the satellite’s useful life by 5 to 10 years. But the reserve boosters had never been used before. If something had damaged them during CryoSat’s 13 years in orbit, there was a small chance the mission would end immediately after the change, reports the ESA.
CryoSat is ESA’s satellite dedicated to measuring the thickness of polar sea ice and monitoring changes in the ice sheets covering Greenland and Antarctica. The mission was designed to last approximately 5 years. It has been in orbit for more than 13 years.
CryoSat uses compressed nitrogen to maneuver in space. The gas is stored under high pressure in a fuel tank and transported through a series of pipes and valves to the thrusters. The thrusters release the gas into space, pushing or rotating the satellite in any commanded direction.
Fuel consumption was not expected to be a limiting factor for CryoSat. But in 2016, operators flying CryoSats at ESA’s European Space Operations Center (ESOC) in Darmstadt, Germany, noticed that the spacecraft was consuming its 37 kilograms of compressed nitrogen much faster than expected.
At the moment, CryoSat has 13 kg of fuel left13 kg less than what it should have according to the use of the thrusters for orbit maintenance maneuvers and attitude control.
When the fuel tank drops below 5 kg, the satellite will no longer be able to reliably control its pointing direction or maintain its orbit.
WHAT CAUSED THE LEAK
CryoSat’s nitrogen propellant is stored in a high-pressure fuel tank. A pressure regulator converts air to high pressure at a much lower pressure for the thrusters to use.
Together with experts from the satellite manufacturer, Airbus, the ESA team has identified the location of the leak on one of CryoSat’s smallest attitude boosters.
The leak rate was small at first, but it increased over the first few years and reached a stable rate that would still see the CryoSat mission end in 2025.
An explanation for this could be that A small crack appeared somewhere and grew to a certain size before stopping. But it is difficult to diagnose this type of problem from the ground and it is impossible to know for sure, according to the ESA.
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