Pulsed plasma thruster

Due to the force of the ablation, the plasma is propelled at low speed between two charged plates (an anode and cathode).

While the thrust is very low, a PPT can operate continuously for extended periods of time, yielding a large final speed.

NASA's research PPT (flown in 2000) achieved an exhaust velocity of 13,700 m/s, generated a thrust of 860 μN, and consumed 70 W of electrical power.

[1] PPTs are very robust due to their inherently simple design (relative to other electric spacecraft propulsion techniques).

PPTs are well-suited to uses on relatively small spacecraft with a mass of less than 100 kg (particularly CubeSats) for roles such as attitude control, station keeping, de-orbiting manoeuvres and deep space exploration.

Howe Industries claimed that should PPT/PPR propulsion technology succeed in becoming a fully functional means of propelling space ships to Mars, then PPT/PPR technology should be capable of shortening travel time to Mars, down from the current requirement of approximately 1 year, to a much shorter travel time of only 2 months.

Howe Industries further stated that at the current rate of their PPT/PPR research and development program, the technology may not be fully ready to propel a crewed space ship to Mars for approximately another 20 years (as of 2024).