Hi Tom -

No doubt if Nixon had approved the pressurized gas fed liquid boosters for the Shuttle, the US launch industry would now be unapproachable in terms of cost and reliability.

But he didn't. Neither did the Congress fund Goldin's back-up for the X-33, which if anyone remembers was supposed to be flyng by 2005.

So what you have to do NOW is look at the cost of keeping a Shuttle C along with the EELVs, and here you have to look at the payloads, and what kind of lift those payloads require -

My best estimate is Dark Horse for manned flight, with the mini-shuttle engineering kept as a back-up, along with the use of EELVs for unmanned payloads. I think the EELVs could be moved to a cluster of 5 from the current cluster of 3 if payload demand warranted a heavy lift launcher...

ep