[GSlob]

For balance problems - I was under the impression that shuttle engines are vectorable. Attachment support would have to be engineered in.

[Jotmo]

What ya gona do bout that big ol' vertical stabilizer. Kinda in the way.

[Calvin Locke]

I was under the impression that shuttle engines are vectorable.

Regardless, why would you want to carry/expend fuel for "balance"?

Doesn't that sort of add to the already poor economics?

[SunkenCiv]

Oh-kay.

GSlob: For balance problems - I was under the impression that shuttle engines are vectorable. Attachment support would have to be engineered in.

The STS main engines (as well as the SRBs) are indeed dual gimbal.

Each engine can be gimbaled plus or minus 10.5 degrees in the yaw axis and plus or minus 10.5 degrees in the pitch axis for thrust vector control by hydraulically powered gimbal actuator.

However, the bulk of the thrust comes from the SRBs. The original vision for the shuttle was a vehicle which could both take off and land like a plane (I think that's what dhuffman@awod.com referred to above. That proved to be too much to engineer (and the engineering was superb back then as well), so we wound up with a rocket launch and glider reentry / deadstick landing.

The tiles are of different materials, all of them insulating from reentry heat, but cooler areas of different materials to save weight, but obviating the need for the large payload bay (by using an unmanned Big Dumb Booster instead) and building a small, crew-only reentry vehicle would make more sense. NASA was smart to go for a one-size-fits-all solution, because without the STS (and later, the ISS), there might be no NASA.

It would have made more sense -- assuming politicians and pork barrels weren't involved -- to have a BDB (actually a series of them) and a man-rated booster to lift a crew of, say, seven into orbit aboard a right-sized crew vehicle. Satellite launchers almost play the role of a series of BDBs, while the new crew vehicle in the middle of the planning stages will be the right-sized crew vehicle. The Shuttle capability will be retired after its long run.

BDBs versatility includes being used to assemble manned interplanetary missions and renewed missions to the Moon.