"OM" wrote in message
news
On Mon, 20 Feb 2006 15:42:32 -0000, "Brian Lawrence"
wrote:

"OM" wrote:

...Here's one that hit me this evening, and I'm surprised none of us
have ever asked this befo When the CSM stack was put into the
Passive Thermal Roll - or BBQ Roll - was it done clockwise or
counter-clockwise? And was there a preference, and if so, why?

Supplement 2 to the Apollo 8 Mission Report


http://ntrs.nasa.gov/archive/nasa/ca...1974072935.pdf

has a section on PTC starting on page 82 of the PDF file (page 6-1 of the
original
doc.).

"PTC roll rate was introduced by five minus roll axis firings between
GET
11:13:38 and 11:13:40."

"Minus roll" would be to the left or anticlockwise I believe?

...Yep, but the questions of why and was this SOP still remain.

I'm thinking that on the unit circle angles are measured as anticlockwise =
positive. For example, so that sin ?/2 = 1. If, on the spacecraft, minus
roll is defined to be anticlockwise, I'm wondering what made them reverse
the normal practice.