Robert Zubrin is the head of the Mars Society and has written several books how to really do space exploration. I like his engineering, though his philosophy comes off as a bit naive sometimes. Still, he knows his stuff.
On space.com last week, he discussed the new plans to go to the Moon and to build a "heavy lift vehicle" or HLV. We'll need this to get to the Moon and planets. He also discussed the Shuttle, of which he is obviously not a fan. NASA wants to keep the Shuttle going for a few more years to complete building the space station, as well as repair Hubble.
The only really time-critical shuttle mission is Hubble Space Telescope repair. This is indeed a truly important mission, and it should be flown with dispatch, as it is without question worthy of the 2-percent risk to crew that any shuttle mission must entail. But the rest of the shuttle manifest is devoted to space station construction, and these cargos could be delivered much more expeditiously by the HLV that NASA needs to develop to reach the Moon anyway.
Griffinâ€™s HLV design will be able to deliver 125 metric tons to low Earth orbit. The shuttle can only deliver 20 tons. With a single launch then, the HLV will be able to deliver as much payload as the shuttle program can during a year â€” and thatâ€™s during a good year.
Compared to current shuttle launch rates, which will have managed only one flight between February 2003 and February 2006, (at a cost of $15 billion), the HLV will be able to launch in an afternoon everything the shuttle program would be able to launch for the next 18 years.
I wonder how accurate that statement is... usually a comparison like this is an oversimplification. Still, it does show how wasteful the Shuttle is, and how we should work on a better vehicle to replace it sooner rather than later.