Das englischsprachige Wikipedia beschreibt die Gründe für das automatische
Shuttle-Rollprogramm aktuell wie folgt:
"During the launch of a space shuttle, the roll program is simultaneously accompanied by a pitch maneuver and yaw maneuver.
The roll program occurs during a shuttle launch for the following reasons:
To place the shuttle in a heads down position
Increasing the mass that can be carried into orbit
Increasing the orbital altitude
Simplifying the trajectory of a possible Return to Launch site abort maneuver
Improving radio line-of-sight propagation
Orienting the shuttle more parallel toward the ground with the nose to the east"NASA
beschreibt die Gründe so:
"Ascent Guidance and Flight Control Training Manual":
"During the vertical rise phase, the launch pad attitude is commanded until an I-loaded V(rel) sufficient to assure launch tower clearance is achieved. Then, the tilt maneuver (roll program) orients the vehicle to a heads down attitude required to generate a negative q-alpha, which in turn alleviates structural loading. Other advantages with this attitude are performance gain, decreased abort maneuver complexity, improved S-band look angles, and crew view of the horizon. The tilt maneuver is also required to start gaining downrange velocity to achieve the main engine cutoff (MECO
) target in second stage."
Das mit der Sicht auf den Horizont scheint für den Notfall wohl hilfreich.