How would the Space Shuttle have performed each of the following maneuvers during ascent?

  1. Pitching the nose away from the external tank ($+$Y).
  2. Pitching the nose toward the external tank ($-$Y).
  3. Yawing right ($+$Z; yawing left would presumably be the mirror opposite).
  4. Rolling clockwise ($+$X; rolling counterclockwise would presumably be the mirror opposite).

I'm looking specifically for which engines would be gimballed for each maneuver and in which direction. It is my understanding that engines were not throttled nor were the flight surfaces adjusted for attitude changes, but if I am mistaken, please include those changes as well. Assume that the solid rocket boosters are still operating.

In practice, attitude control during ascent was automated and performed in combination as needed, rather than the individual maneuvers of this question. This answer describes the two programs that normally occurred in ascent, and this answer describes how deviations from the intended attitude were automatically corrected. However, those answers still describe actions as pitch/yaw/roll, rather than how those are performed by the engines.

shuttle axes

Also related: Pitch and yaw axes of rocket systems such as Apollo


1 Answer 1


During first stage both the SSME engines and SRB nozzles gimbaled to provide thrust vector control (TVC); the SRBs provided most of the control authority due to their long moment arm and high thrust.

For all of your sub-questions, the TVC would move the thrust vector slightly to rotate the vehicle in the desired direction.

Nose up pitch: nozzles deflect up

enter image description here

Left yaw: nozzles deflect left

enter image description here

Right roll: left nozzles deflect down, right nozzles deflect up.

enter image description here

Reverse the deflections to go in the opposite direction.

The elevons deflected slightly in first stage for aerodynamic load relief, but not for vehicle control. Throttling was not done for attitude control. The c.g. location in the pictures is representative only.

Original picture from here

Read about the Ascent Thrust Vector Control system in detail in the SCOM page 2.13-45 forward.

  • 1
    $\begingroup$ It is interesting to note that the gimbal directions for the SRB engines were defined to be "rock" and "tilt" (compare this to the defined gimbal directions for the SSMEs - "pitch" and "yaw"). $\endgroup$
    – Digger
    Oct 4, 2019 at 17:29
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    $\begingroup$ Yeah - it seems to be the way the actuators were mounted, and I never really got why. But the "rock" and "tilt" could work together to give you a pure "pitch" or whatever. $\endgroup$ Oct 4, 2019 at 17:30

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