NASA's Proposed Plasma Rocket Could Get Us to Mars in 2 Months?

[Loren Pechtel]

Mars is an interesting nut because even if we shortened the trip to Mars, it is arguable we've made the problem of the trip even harder. Unless I'm mistaken, the soonest we can leave Mars is about one year after leaving Earth (and that is assuming a certain velocity, if we are traveling quicker, presumably we have to wait longer on/in/around Mars). Arriving at Mars quicker doesn't actually gain us anything unless we can live on (in?) Mars. And living on (in?) Mars is way way way down the road.

This isn't Pikmin, where we have infinite power to ascend back up to the mothership every day, and there are no fruit for us to harvest.

If we can get there in 2 months we aren't constrained to Hohmann orbits. While there are clearly unacceptable transits neither is there a need to wait for a perfect alignment. I'm having no luck finding a porkchop plotter that can handle this sort of energy.

 

[lpetrich]

•  List of missions to Mars
• Every mission to Mars ever | The Planetary Society
• Mars Exploration Timeline - NASA Goddard Space Flight Center

Nearly every mission to Mars was launched around some Hohmann-orbit departure time.

The most recent launches were in July 2020, and Mars explorers passed up the opportunity of August 2022. The next opportunities are in September - October of this year, and in November 2026, January 2029, and February - March 2031.

 

[lpetrich]

Adding to my list of successfully-flown rocket engines, I add

(Aerozine 50) - NTO (Titan IIIE LR91): 3.1 km/s, 1.9 MN

Its propellants:

• Aerozine 50 = half-half by weight of hydrazine and UDMH
• Hydrazine = N2H4 -- 2 C to 114 C
• UDMH = unsymmetrical dimethylhydrazine = (CH3)2N - NH2 -- -57 C to 64 C
• NTO = (di)nitrogen tetroxide: N2O4 -- -11 C to 22 C

I've included the range over which these propellants are liquid. While these propellants are liquid at room temperature, they are very toxic and NTO is also very corrosive.

Rocket-grade kerosene: RP-1 -- much like jet fuel -- much less toxic. One has to drink it to be poisoned by it.

Oxygen and hydrogen are both cryogenic propellants, meaning that they have to be kept *very* cold to keep them from boiling. Their boiling points:

• O2 -- 90 K -- -183 C
• H2 -- 20 K -- -253 C

 

[lpetrich]

Readiness, other features:

• Chemical engines: 9 -- high thrust, low EEV
• Ion engines: 9 -- high EEV, low thrust
• Solar sails: 7 -- low thrust, no onboard propellant
• VASIMR: 5 -- high EEV, low to medium thrust (?)
• OP's system: 2

 Solar sail - listed as 7 because the Planetary Society flights seem to be of full-scale versions.

 Variable Specific Impulse Magnetoplasma Rocket (VASIMR) -- projects EEV's around 50 km/s and thrusts up to 5 N -- about 35 to 55 times better than present-day ion engines in thrust and only a little bit better in EEV.