Nuclear engines could be reality.

[Spica]

For a possible fuel for an NTR, I might use water.

Its quite dense, and contains plenty of hydrogen. Furthermore, it is VERY storable, and can be used for radiation shielding and life support.

To use it as fuel, I would just use electrolysis to separate out the hydrogen. The power would come from the nuclear core of the NTR.

The remaining LOX can be used for oxygen, or also used in the NTR, for more thrust when needed.

[Nibb31]

We should be focusing more on technologies and design solutions for orbital fuel storage, ISRU, and propulsion technologies in the present- rather than sending robotic probes for Planetary Sciences. It's only so long that you can analyze a planet with sensors and rovers before you start running out of useful things to learn with unmanned missions...

Robotic probes give us the biggest science return for the lowest effort. There is nothing that you can learn from a manned mission that you can't learn from a robotic mission (other than studying the human himself). It's just a matter of cost of designing and carrying the experiment there. For the foreseeable future, sending a robotic experiment will always be cheaper than sending a manned experiment, plus the man, plus the equipment to keep the man alive and sane and to bring him back when he's done.

Robotic probes have the avantage of costing less, covering more ground, doing longer missions, and don't need to come back. You can potentially learn more from 20 rovers running for several years in different locations than from 1 manned mission for 3 months in a single spot.

Humans have the advantage of quicker reaction times and faster understanding of their surroundings, but those are not major advantages when it comes to planetary science. There is no need for quick reaction or fast understanding because we are in no hurry.

For a possible fuel for an NTR, I might use water.

Its quite dense, and contains plenty of hydrogen. Furthermore, it is VERY storable, and can be used for radiation shielding and life support.

To use it as fuel, I would just use electrolysis to separate out the hydrogen. The power would come from the nuclear core of the NTR.

The remaining LOX can be used for oxygen, or also used in the NTR, for more thrust when needed.

The point of using H2 is that it provides the highest amount of energy for the lowest volume. Volume means weight, but it also means tankage, which also means weight. Other fuels can only provide the same amount of energy with a higher energetic density, which means that your spacecraft is much heavier and requires even more propellant.

The weight advantage of using an NTR is that you only need H2 and no oxydizer. If you are going to haul up H2O and the equipment to separate it into H2 and O2, then you lose the weight advantage of using a NTR in the first place.

[xcorps]

You, sir, have a fine talent for understatement.

If it weren't for the military providing reasonable and workable guidelines for satellite launches there would have been no shuttle program costing only a billion a launch. So nyeh.

[KvickFlygarn87]

Tubes of uranium and plutonium can produce extreme amounts of heat, heat can be used as a source of propulsion.

#NorthKoreanScience

Wow

Such science

Very tech

Much new

[Red Iron Crown]

If it weren't for the military providing reasonable and workable guidelines for satellite launches there would have been no shuttle program costing only a billion a launch. So nyeh.

I dunno, that was back when US military procurement actually worked to some degree. Now it seems like they're entirely incapable of developing and deploying things in any kind of timely fashion or to a specified budget. So the militarization of a NERVA-like program would likely mean decades before a usable system emerged, if then.

[xcorps]

I was being totally facetious.

[Red Iron Crown]

I was being totally facetious.

Sorry, my sarcasm detector is in the shop getting calibrated.