5
$\begingroup$

I found this super helpful plot of the Saturn V pitch angle vs time during launch:

enter image description here

Is there an equivalent plot for a typical (or atypical if must be) Falcon 9 launch?

$\endgroup$
6
  • $\begingroup$ isn't pitch supposed to be measured w.r.t horizon?!? But even if it's measured w.r.t zenith, how is it supposed to cross 90°, meaning pointing down to Earth?!? $\endgroup$ – jumpjack Dec 16 '20 at 9:18
  • 1
    $\begingroup$ I am no expert but I'd guess that in this plot pitch is inertial relative to T+ 00:00:00 Once in orbit it should change at about 4 degrees per minute (360 degrees in 90 minutes). To get the angle relative to local horizontal one would have to have more information about the ground track or downrange distance or the actual trajectory. $\endgroup$ – uhoh Dec 16 '20 at 10:21
  • 1
    $\begingroup$ Just keep in mind that Falcon9 can (I think) support different missions, i.e. different orbit altitudes, and the pitch profile is likely to differ depending on the terminal orbit parameters. $\endgroup$ – Carl Witthoft Dec 16 '20 at 13:13
  • 1
    $\begingroup$ As you can see, @uhoh pitch freezes during staging events, which confirms it's in a non-rotating frame. which all but confirms your guess. $\endgroup$ – user20636 Dec 16 '20 at 14:14
  • 2
    $\begingroup$ Agreed, the angles are relative to the vehicle's inertially-stabilized platform IIRC. history.nasa.gov/afj/ap12fj/pdf/… table 5-VII gives the pitch in local horizontal coordinates. Table 5-X matches the plot above. Lots ot great stuff in this document. $\endgroup$ – Organic Marble Dec 16 '20 at 14:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy