The Ares 1-X is part of the latest attempt by NASA to develop a shuttle followon. There have been quite a few attempts in the past, this one has gotten farther then most.
The Ares 1 will (if it is built and that is iffy) have a 5 segment solid rocket booster as its first stage and a second stage with a modified J-2 on it (the Saturn third and second stage engine).
The 1-x is really a "test" vehicle. The only active part of it is an old Shuttle SRB (which is a four segment solid), a dummy fifth segment and the rest is all boilerplate. The flight will last under 2 minutes. So far it has cost over 600 million dollars. The entire project to date has consumed 9 billion more. The actual vehicle will be as expensive as the shuttle to launch. (if that can be believed)
There are a number of "what ifs" ...no one has ever human rated a vehicle with a solid first stage. The USAF looked at doing that with the MX and figured out that the thing would shake the crew very badly. But the "rocket scientist" at NASA are smarter then everyone else and they think that they ahve the pogo issues solved. Some good guesses are that the vehicle will have pogo of about 10 percent of thrust...that would be a pretty tough ride.
Of course the USAF is not for sure that it wont hit the tower on launch...so who knows.
Robert WB5MZO
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