Any Aero/Astronautical Engineers in the house?

[SeaCat]

Watched the shuttle launch this afternoon and loved it. (I haven't missed one yet.) I have a question about the launch that I have asked before and still haven't received an answer that makes sense to me. (Granted it may be that my feeble little non Engineer mind just doesn't understand.)

Just after the launch the Shuttle rolls onto it's back. This is to reduce the stress on the attachments between the Orbiter and the rest of the Shuttle Package. (The solid fuel boosters and the main tank.) This I understand.

What I don't understand is why the shuttle rolls instead of just leaning backwards. Wouldn't the roll induce more stress on the shuttle then just leaning back. (Lateral as opposed to linear stress.)

Cat

 

[DesertPirate]

Never thought of that!
I suspect if it made a difference they would orient the launch pad so it could lean, instead of roll.
That's my guess anyway.

The part that gets me is 1000 feet in altitude and 1300MPH. That sucker gets one hell of a hole shot!

 

[Owlwhisper]

.....

 

[DesertPirate]

The really strange part?
I almost understand all of that!

Wow, I was even partially right

 

[Weird Harold]

Here's an explanation from a NASA person, with a translation into reasonably non-tech language. What it boils down to is that the shuttle should be oriented a particular way during ascent, and the launch pad isn't -- so a roll is needed. A simple tilt won't accomplish the reorientation that is needed.

It's only hinted at in that explanation, but another factor is that the Shuttle doesn't launch on the same heading every time -- it goes generally east but an equatorial orbit and a polar orbit require different headings, so re-orienting the launch pad would only reduce the amount of attitude adjustment required, not eliminate it.

 

[JAMESBJOHNSON]

The members of Congress should operate NASA like they do GM and the banks and healthcare. I'll bet a launch would be something to see.