Most promising form of space propulsion?

[merovingian12]

Hello,

I'm a second year physics student and I'm interested in new approaches to spacecraft propulsion. I apologize if this has been asked many times - while this interest may be partially inspired by science fiction, I am well aware that the real-life situation is not at all as glamorous. But, I would still like to make a contribution of some sort.

I would be very grateful if someone who is in the know could give me some guidance. What are some of the potentially superior alternatives to chemical propellant? I'm vaguely aware of ion thrusters as well as nuclear and electric propulsion, but that's about it. Are there any other proposed methods? Do any of them seem particularly promising?

Thank you very much for your help.

 

[Travis_King]

You should specify whether you mean propulsion for earth-to-orbit, for orbital maneuvers, or for potentially both. That'll help get the ball rolling in a more specific direction.

 

[merovingian12]

I was thinking more along the lines of interplanetary and interstellar travel in general, so potentially both of those would play a role.

 

[D H]

With regard to interstellar travel, who knows. We have *nothing* that even approaches that capability now, and there's nothing on the horizon that approaches it, either.

With regard to interplanetary travel, are you asking about automated probes or vehicles capable of carrying humans? Machines can tolerate years or even decades to move from point A to point B in space. Humans can't.

 

[etudiant]

The nearest propulsion advance for higher speed interplanetary transits is the VASIMIR plasma rocket concept.
This is at the demo stage, although afaik no full scale unit has been built and no model has been space tested.

There have been other concepts using nuclear reactors to provide rocket energy from hot hydrogen, but the engineering problems of keeping a reactor together while red or white hot with a torrent of hot gas rushing through it have proved daunting.

AS DH points out, for automated probes low power plasma is very efficient propulsion and by judicious course selection to take advantage of the various gravity fields, probes can go a very long way in the solar system on a relatively minute fuel supply.

For interstellar travel, there are science fiction proposals using square mile sized solar sails or spaceships powered by a stream of nuclear explosions ( See Project Daedalus) but 'nothing' really even close to tangible.