NASA launched its Psyche mission to visit a weird metal asteroid in October 2023, and since then the spacecraft has been on its way through the solar system to its final destination located in the main asteroid belt between Mars and Jupiter. However, NASA announced this week that the spacecraft is experiencing a problem with its thrusters and it is currently coasting.
Psyche has an unusual propulsion system which uses ionized xenon and which gives off a blue glow. These thrusters use tiny amounts of xenon and expel charged atoms to move forwards. While electric thrusters are often used in low-Earth orbit such as for satellites, it is rarer for them to be used in deep space missions.
This system only produces a tiny amount of thrust, but that is all that is necessary in the vacuum of space to move the spacecraft. The thrusters are so efficient that they could run continuously for years before using up the 2,000 lbs of fuel on board.
Now, though, it seems that the fuel pressure in the system has dropped, going from 36 psi to around 26 psi. NASA did not state how quickly this drop had occurred, but it did say that the thrusters were automatically shut off due to the pressure drop.
At this time it’s not known what caused this drop in pressure , but NASA says it has a few weeks to work on the problem before the lack of thrusters will have an effect on the mission.
“The mission team has chosen to defer thrusting while engineers work to understand the pressure decrease,” NASA wrote in an update. “The mission design supports a pause in thrusting until at least mid-June before the spacecraft would see an effect on its trajectory.”
There is also a backup of sorts, in that there are two fuel lines leading to the propulsion system. If necessary, Psyche would switch to using its backup fuel line instead of its primary and could potentially keep using the thrusters that way.
NASA personnel aren’t significantly concerned about the issue at present though, a representative said this week.
“This kind of thing happens and that’s why we build redundancy into our missions,” Louise Prockter, director of NASA’s planetary science division, said at meeting of the Mars Exploration Program Analysis Group, as reported in SpaceNews. “We don’t have any concerns at the moment about it but we’re obviously keeping tabs on it.”
