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On the topic of Phobos, the wiki article on the moon notes that it appears to be covered with thick layers of fine regolith. This may have near term application as propellant for the large ship that Robert is developing.
I have already written about using fibre lasers to vapourise this material and accelerating the resultant plasma using an arc jet. There are three problems with this idea: (1) Even fibre lasers are relatively inefficient and power hungry; (2) If the propellant does not vaporise uniformly, the reaction chamber and laser optics could end up being peppered with molten rock particles; (3) Oxygen ions in the plasma, would attack the arcjet cathode, limiting its life.
An alternative would be a modified VASIMR engine.
https://en.m.wikipedia.org/wiki/Variabl … sma_Rocket
We inject pellets consisting of 10% water ice and 90% micron sized regolith fines. Radio frequency generators would heat the water to millions of Kelvin, forming a plasma of hydrogen and oxygen ions. The micron sized dust particles would be vaporised by molecular collision and radiated heat. The resulting mixed plasma is contained away from the engine walls by a strong solenoid static magnetic field. This functions as an expansive engine nozzle at the rear of the engine.
With an exhaust velocity of 50km/s, a large ship should be able to fly from low Mars orbit to LEO and back on a single propellant load. This would allow Phobos regolith to become the source of some 90% of propellant reaction mass. The other 10% can be recycled black water from the ship. This is convenient, because Phobos L1 point is only about 1km above Stickney crater. The large ship could dock there on its return flight to Earth. It should therefore be simple to refill the ship with propellant dust from a small facility on Phobos.
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For Calliban re new topic!
Best wishes for success with this promising new topic!
For all members: Please encourage anyone you may know, or have a friend who knows, someone able to assist with development of this idea. We are in need of physicists and engineers to assist. Persons with experience developing, maintaining or operating mass accelerators would seem likely candidates to assist with this topic.
The VASIMIR concept appears (as I understand it) to be limited to a very small number of ions. The concept of this topic appears to be able to employ a wide variety of materials for propulsion.
Anyone who would like to assist with this topic who is not currently a member of the forum is welcome to apply. See Recruiting topic.
(th)
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