4 ms·

There's not actually gas, or a tank. Most space probes like this are powered by radioactive decay of a plutonium core.

• greglindahl 9y ago
  Cassini is far too old to have ion thrusters -- and even ion thrusters use reaction mass. There is a plutonium RTG that generates electricity. That's used for heaters and powering the science instruments and communications gear.
• jakebasile 9y ago
  That's used to generate electricity. The spacecraft still use propellant when they need to generate thrust.