Why does the Space Shuttle roll after take off?

Question

Why does the Shuttle roll after take off (it rolls about 100 degrees or so just after clearing the tower). Why does it do this - and what would happen if it didn't? Thanks.

Answer 1

The vehicle lifts off the pad 0.3 second after SRB ignition, rising vertically in attitude hold until the SRBs' nozzles clear the lightning rod tower by approximately 41 feet. The vehicle begins a combined roll, pitch and yaw maneuver that positions the orbiter head down, with wings level and aligned with the launch pad. The orbiter flies upside down during the ascent phase. This orientation, together with trajectory shaping, establishes a trim angle of attack that is favorable for aerodynamic loads during the region of high dynamic pressure, resulting in a net positive load factor, as well as providing the flight crew with use of the ground as a visual reference. By about 20 seconds after lift-off, the vehicle is at 180 degrees roll and 78 degrees pitch.

If the vehicle did not roll upside down, the pilot would not have a ground reference out the window. Also, the g-forces push the astronauts down as the shuttle arcs towards the horizontal; any other roll position would cause side forces or try to lift the astronauts off their seats, even as they are pushed into the back cushions; uncomfortable at best. Lastly, this is the best position to reduce loads on the shuttle during ascent.

Answer 2

I don't know why somebody gave a thumbs down to the first answer. It's very close to right. A little more info.

They use the old pad because it made no sense to build a new pad in a specific orientation. Depending on the mission, the Shuttle goes into different orbits. So it would always have to make a course change after liftoff, which is what the roll is, it sends the Shuttle into the proper orbit, whatever that might be.

There's also a dynamic advantage to having the Shuttle rockets underneath the main loads, it's more stable to compress the pieces together than it is to be pulling them apart

Answer 3

There are 3 reasons. First, the return and forth reaches a element approximately one minute after launch whilst the stress stress of the ambience dashing previous the immediately accelerating rocket reaches a top. The roll maneuver is achieved almost immediately earlier max q is reached because of the fact this "heads-down" orientation enables alleviate the stresses that the dynamic stress plenty reason on the motor vehicle's shape. the 2nd ingredient we would desire to evaluate is that for each project, the return and forth could launch at a undeniable azimuth attitude with the intention to be inserted into the final orbital plane. because of the fact the launch pad (and subsequently the return and forth) sits in a fixed place, the return and forth could carry out a roll maneuver for the time of ascent with the intention to orient itself to realize the needed launch azimuth attitude. If it have been available to rotate the launch pad ahead of launch, the pad could merely be became around to accomodate the launch azimuth attitude, and the return and forth could launch right into a heads-down orientation on the same time as progressively pitching over for the time of ascent. ultimately, the return and forth orbits such that its shipment bay faces in direction of the Earth. The heads-down place assists in communications with the floor and enables gadgets in the shipment bay to be pointed back in direction of Earth, that's needed for many of the experiments carried in the bay. there is in all probability additionally some psychological earnings to the team because they are given surprising perspectives of homestead extremely than staring into the chilly darkness of the super void of area.

Answer 4

Well, to those who think it's because they use the old Apollo launch pads...then why did the Saturn V's used in the Apollo missions perform the SAME roll manuever? (And indeed they did, just harder to notice it with a round rocket.) BZZZT!! You guys got it wrong, and rfgrinnel got it exactly right. You'd be amazed what you can learn by actually looking at the NASA website.

Answer 5

It takes less effort on the flight control surfaces to "aim" the shuttle to where it needs to be. The rockets are placed over the craft, with respect to gravity, and uses less fuel to accelerate while following the rotation of the earth.

Answer 6

I think it is just because they are using the old Apollo launch pad which isn't facing the way they want the shuttle to go, so instead of building a new launch pad, they just make that roll after takeoff. It is just a cheap and easy fix compared to building a new pad.

Answer 7

The first answer is the winner!

And I don't care about that behemoth. And arrow doesn't care if it fly right side up or down. My friend, the engine configuration is different!

Answer 8

This positions the heat absorbing tiles to be the leading edge while going through the atmosphere. Else it would burn up.

Answer 9

Gravity.