Gee, frodo, why haven't you been supporting my concept? Oh, well, never mind, this is bringing a lot of lurkers out of the woodwork.
And welcome to all of you quarks!
The only problem with the Delta and Atlas variants is that they just don't have the oomph to put manned capsules in any usable orbit. Which means designing a new rocket. Or, hiring the Russians to taxi us back and forth.
To whoever was saying that the early designs for the space shuttle were for vertical launching, we are talking back in 1968, when NASA was still golden. The engineers who got us to the Moon figured out that an air launched orbiter based on a lifting body design was the best way to go. Then, Congress decided that they were better at designing spacecraft than the engineers were, and we got the shuttle.
Why is it that people who are literate cannot understand that we are, at minimum, 100 years away from being able to build a space elevator? At least two folks have said the heck with this poll, lets live in fantasy land. Carbon nanotubes less than an inch long aside, we just don't know how to make a cable that will support its own weight when it is 23,000 miles long. PERIOD! Which means that we have to figure out how to accelerate our victims to 17,500 miles per hour, 5 miles per SECOND, to put them in orbit. And then de-accelerate them on the way back.
Just because the space shuttle didn't make it back when there was a big hole in the leading edge of the wing does not mean that there is an inherent flaw in the lifting body re-entry concept. It just means that we have to be careful with our spacecraft. Returning from orbit in a capsule may be the safest way to get through the hypersonic barrier, but it leaves you with the problem of landing. (Or watering, as was the case with the U.S. capsules.) And we have not even tried to land a capsule big enough to hold ten people.
Even though I am an advocate of using a catapult, I am not trying to create a meteor shower with the spacecraft. Which is what you will get if you accelerate a vehicle to a velocity at sea level, Denver level, or mountaintop level of one mile per second. Just cannot be done.
Everyone seems to think that we are looking at sending up a few people every few months for the next 20 years. Probably because they only think about going to Mars, and you don't need a bunch of people to go to Mars. When we go to Mars, it will be because so much money has been made from processing materials in space that developing the life support systems needed for a multi-year voyage will not seem expensive. We will not go to Mars because everyone thinks it would be cool, or because we could live there after a thousand years of terraforming. We will go to Mars because we will have so much money floating around that it will not be a big deal. In order to create all that wealth, we have to figure out how to get people, lots of people, into Low Earth Orbit, and to bring them back again. That is what I believe frodo is driving at; what launch system will be best for high volume launches (not loud, but frequent,) carrying 10 people into LEO. And by best I would assume that he means; cheapest, safest, and quickest.