What supports rockets/the shuttle prior to launch?

[gt0163c]

So, I was thinking about launching rockets and the shuttle the other day (during a less than interesting meeting at work). And I got to wondering, what supports a rocket and the shuttle when it's on the launch pad prior to takeoff. Do rockets sit on the nozzles, like model rockets do? Are the rockets supported somehow by pins/beams which connect horizontally to the launch tower? Is there something else I'm not thinking of.

I'm guessing it's either totally the latter or at least a combination of the two. I'm thinking that rockets are heavy, nozzle geometry is incredibly important and the possibility of warping a nozzle due to supporting that amount of weight just on the rim of the bottom edge would be high. But, I could be wrong.

Can anyone share some information/shed some light on this question?

[ApolloXI]

I am not 100% sure but I think the ET is concocted too two supports that have mechanical hand like objects that hold the shuttle stack to the pad. Plus I think there pins the that hold the shuttle Stack up so that the SRB nozzles are not hitting the pad. When the SRBs are ignited the mechanical hand like objects let go and the pins are blown up by small explosives.

[Boomerang]

Actually the hold down mechanismsare connected to the base skirt of the SRB's the nozels are not sitting on the mobile launch platform but more in the flame trench area or atleast right above it. If you watch a launch when the Main engines ignite the shuttle lunges somewhat in the direction of the ET as the engines come up to full thrust remember it takes aproximately 6 seconds from the ignition sequence start to the engines being at full throttle as the engines come up the shuttle leans back toward the orbiter again at T-0 the stack is again verticle and if the engines are at full thrust the boosters are ignited and the shuttle launches if they arent coming up fast enough the computer shuts the engines down before SRB ignition and you have a redundant launch sequencer abort. My point in going threough all this is to show the SRB nozels cant just sit on the mobile launch platform they have to have that sway when the engines ignite. The hold down points themse;ves use an explosive charge that releases the boosters upon ignition allowing the shuttle to launch.

[Benji]

The SRBs support the entire stack on the pad. This makes sense; the braces are strong enough anyways because they end up supporting the whole stack while they're dragging it up. The SRBs are attached to the MLP so that the flames go directly into the trench (at least at first) while the SSMEs hang down a little further into the trench area. When the SSMEs are ignited, the stack sways as Jason mentioned, but this movement is minimal at the base of the SRBs because of the bolts. Search here for 'mobile launch platform' and select videos, the first couple are pretty cool and kinda illustrate what I mean.

[gt0163c]

Benji, thanks for the link. This video seems to show the SRB support best: http://spaceflight.nasa.gov/gallery/vid ... srbign.mpg. If you pause the video just after the footage inside the SRB (shows the 11 pointed star of the fuel inside the SRBs), and then step forward a few frames, you can see the bolts around the skirting towards the bottom of the SRB. Far as I can tell, that's what the whole stack is supported by.