"In any event, we have finally realized the propulsion systems we have used for Apollo and the Space Shuttle program will not cut it anymore. If we stick with the old stuff, we will be stuck in the rut (from a space travel perspective)."
I get a kick out of reading about the future of space travel. Much of what I have been reading, is almost thinking like a cave man. In other words, it took Apollo 11 four days to get to the Moon. Back then, to get to the Moon, Apollo 11 traveled at a bit over 24,000 mph. That sounds very fast compared to freeway driving back on Earth.
But for space travel, especially interstellar, 24,000 mph is like standing still. Chemical propulsion, be it liquid or solid, is so yesterday. I read an article not too long ago, that to power a spaceship to go from here to Alpha Centauri (using today's chemical fuel), not only would it take 200 years round trip (assuming we could power up to 4.5% of light speed), but it would take just about more chemical fuel than exists in the known universe. Bottom line - we ain't going anywhere, until we get a better and faster way of travel.
Enter Project Orion. By the way, Project Orion is not new. It is a concept which has been considered since the turn of the 20th century. It has been written about in science fiction books. But Project Orion was not science fiction. It was science fact. Project Orion is using nuclear fission to power spaceships.
This might sound like it came out of an H. G. Wells book, or a Tom Swift novel. Since this project had been tinkered around with since the 1950's (and the idea, long before that), it almost had enough traction to knock the Mercury, Gemini and Apollo programs off the radar - and replace it with something else. Something else? One of the visions back then was using nuclear propulsion to jump start our trips into space. It would be putting 150 scientists to live and explore on the Moon. Also exploring Mars and the moons of Saturn. Well then, what happened?
As they say in Aspen, we were "over-skiing our ski tips". The technology of having small nuclear explosions go off right behind a space ship to propel it faster, was not yet ready for prime time. So Project Orion was put on the back shelf, and we went full speed ahead with chemical propulsion. But hold the phone! The technology might have caught up with time. We now might be ready to travel down this path again.
In any event, we have finally realized the propulsion systems we have used for Apollo and the Space Shuttle program, will not cut it anymore. If we stick with the old stuff, we will be stuck in the rut (from a space travel perspective). However, the folks at NASA are finally starting to think outside the box.
I think during the 2020's, different nations from Earth will reach out and touch not only the Moon again, but also Mars, maybe some moons from Saturn and Jupiter, and an asteroid or two. To do so, we will be using some kind of new propulsion - maybe even nuclear.
In any event, we are about ready to close the chapter on chemical propulsion. It was good while it lasted, but it is high time to move on.