3
$\begingroup$

Launching from Florida 28.5 degree inclination to rendezvous with ISS at 400km to 51 degree inclination of ISS

$\endgroup$
2
  • 1
    $\begingroup$ Question could be made more clear and specific. As there are many aspects and details depending on exact nature of answers desired. $\endgroup$ Jul 7, 2019 at 12:09
  • $\begingroup$ If you have KSP try launching from the Woomerang launch site to either LEO or an LEO rendezvous ;). $\endgroup$ Jul 9, 2019 at 18:22

2 Answers 2

10
$\begingroup$

The latitude of a launch site determines the minimum inclination that can be directly reached; launching from 28.5º latitude in the due-East direction achieves a 28.5º orbital inclination. Launching to any higher inclination is straightforward, simply by steering continuously North-of-East during the ascent. In the extreme case, if you fly due North, you enter a near-polar orbit (the rotation velocity you receive from Earth before you leave skews things a bit).

$\endgroup$
6
$\begingroup$

In the case of the space shuttle:

These two images show that the flame trenches at KSC point due south, and that the Orbiter's tail when installed on the pad also points due south.

enter image description here

(source: Google Maps)

enter image description here

(source: NASA)

Therefore if the shuttle launched and went into a gravity turn in the desired heads-down attitude without rolling at all, it would have flown due south.

As explained in this answer, a launcher gains the maximum benefit from the Earth's rotational speed if it launches due east. This will place the vehicle into an orbit with an inclination equal to the launch site's latitude - in the case of Kennedy Space Center, 28.5º.

To fly due east and obtain this benefit while maintaining the desired heads-down attitude, it is clear that the shuttle had to roll 90º since it was mounted on the launch pad with the tail pointing south.

However, with the inclusion of Russia in the International Space Station (ISS) project, an orbit inclined 51.6º was chosen to allow the use of Russian launch sites.

For the shuttle to reach this 51.6º inclination, it had to roll even further north to align with this flight azimuth. Therefore, the vehicle performs a single axis rotation (SAR) maneuver, often called the "roll program", after clearing the launch pad, to align its direction of flight with the desired azimuth. This SAR both aligns the flight path with the desired azimuth, turns the vehicle heads-down, and starts the gravity turn.

To minimize the amount of delta-v required to change orbital planes, the launch time for an Shuttle mission to the ISS was set, if possible, to the time at which the ISS orbit passed over the launch site. However, choosing this launch time did not preclude the necessity of rolling to the proper azimuth. If the shuttle had launched at the exact time of ISS orbital plane passage with the desired heads-down attitude and not rolled, it would have flown due south.

In this video taken from a camera on the right-hand Solid Rocket Booster of STS-127, you can clearly see the vehicle roll from tail-south to tail-east. In the video, liftoff occurs at ~0:50 seconds, the roll starts at ~1:00, and at ~1:17 you can clearly see the coastline under the tail.

$\endgroup$
2
  • $\begingroup$ This answer is wrong and then steals from my answer, and answers because of my answer. You've deleted my comments, which I have right to, I was explaining why I down voted as is suggested in s.e. To leave comments. $\endgroup$ Jul 10, 2019 at 0:42
  • $\begingroup$ All because you said the vehicle rolls north but is not necessarily true the vehicle can launch southerly with no delta v cost and further has to for one of the launch windows to the ISS which occur twice a day, which of course you did not mention, which of course my answer did, and which of course is the negative "wrong answer" nice pictures of the shuttle pad, that should really help visialize how Florida vehicle matches inclination. $\endgroup$ Jul 10, 2019 at 0:46

Your Answer

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

Not the answer you're looking for? Browse other questions tagged or ask your own question.