a Q regarding a Space Shuttle launch
I have always been intrigued as to why, during the initial acceleration off the launch pad, the Space Shuttle rolls around 180 degrees. I’ve checked the NASA site <A HREF="http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_mes.html#mes_count" TARGET="_blank">http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_mes.html#mes_count</A> which describes a typical launch.
It says:
First-stage ascent extends from SRB (Solid Rocket Booster) ignition through SRB separation, or SRB staging. The sequence of major guidance, navigation and control events proceeds as follows: 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 manoeuvre 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 favourable 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.
My question’s are:
Why does it have to roll through 180 degrees?
Why can’t they just turn the Shuttle around on the launch pad?
Could it possibly be because of the way the Shuttle comes out of the hangar(ie.orientation)?
Does the Shuttle have to head/climb out over the Atlantic? (I believe the Solid Rocket Boosters splash down in the Atlantic to be reused).
Any takers?