I had a question around how the Space Shuttle handles inertial attitudes around Universal Pointing MFD. I almost have this figured out, but need some help.
In Wikipedia, I read the following regarding the inertial frame:
If the goal is to keep the shuttle during its orbits in a constant attitude with respect to the sky, e.g. in order to perform certain astronomical observations, the preferred reference is the inertial frame, and the RPY angle vector (0|0|0) describes an attitude then, where the shuttle's wings are kept permanently parallel to the earth's equator, its nose points permanently to the [ame="http://en.wikipedia.org/wiki/Vernal_equinox"]vernal equinox[/ame], and its belly towards the Northern [ame="http://en.wikipedia.org/wiki/Polar_star"]polar star[/ame]
I noticed when I engage 0,0,0 and ITEM 18 on the Universal Pointing MFD that indeed, the wings are level to the equator, the nose does point to the vernal equinox, but I am perplexed that the top and not the "belly" of the shuttle points towards Polaris.
Is the Shuttle this way because the Star Tracker is located on the upper nose of the vehicle, or is the INS on the Universal Pointing MFD out by 180 degrees on the roll vector?
Thanks,
In Wikipedia, I read the following regarding the inertial frame:
If the goal is to keep the shuttle during its orbits in a constant attitude with respect to the sky, e.g. in order to perform certain astronomical observations, the preferred reference is the inertial frame, and the RPY angle vector (0|0|0) describes an attitude then, where the shuttle's wings are kept permanently parallel to the earth's equator, its nose points permanently to the [ame="http://en.wikipedia.org/wiki/Vernal_equinox"]vernal equinox[/ame], and its belly towards the Northern [ame="http://en.wikipedia.org/wiki/Polar_star"]polar star[/ame]
I noticed when I engage 0,0,0 and ITEM 18 on the Universal Pointing MFD that indeed, the wings are level to the equator, the nose does point to the vernal equinox, but I am perplexed that the top and not the "belly" of the shuttle points towards Polaris.
Is the Shuttle this way because the Star Tracker is located on the upper nose of the vehicle, or is the INS on the Universal Pointing MFD out by 180 degrees on the roll vector?
Thanks,