I was reading about different sources of propellant for ion thrusters, Xenon being the most common. However, in more recent articles I've found more and more mentions of Solid Iodine being used as ion thruster propellant.
A key advantage to using iodine as a propellant is that it provides a high density times specific impulse, it is three times as fuel efficient as the commonly flown xenon, it may be stored in the tank as an unpressurized solid, and it is not a hazardous propellant. 1U with 5 kg of iodine on a 12U vehicle can provide a change of velocity of 4 km/s ΔV, perform a 20,000km altitude change, 30° inclination change from LEO, or an 80° inclination change from GEO. During operations, the tank is heated to vaporize the propellant. The thruster then ionizes the vapor and accelerates it via magnetic and electrostatic fields, resulting in high specific impulse.
I guess my questions are:
- How can you use solid Iodine as a stand-in for Xenon, do you have to sublimate it?
- Are there any complications which arise from using a solid fuel?
- What makes Iodine so efficient to store as a solid fuel?
- How much more efficient will this be in terms of storage, what are the advantages?
- How much better is the specific impulse than: Xenon/Krypton/Argon?
- How much easier is it to store than: Xenon/Krypton/Argon?
- How much less risky is having Iodine than: Xenon/Krypton/Argon?
- How much less costly is it than: Xenon/Krypton/Argon?
- Is this Iodine Satellite the first one to test this stuff out?
Let me know if those questions should be broken out more, I can make multiple to handle specific questions on the iodine propellant, but I figured I'd start with one broad stroke question.