STS-125

[Nephi]

I just noticed something, well actually a couple of days ago, I keep hearing MC say "Heading Alignment Circle" (HAC) and in the manual it's called "Heading Alignment Cone" -- is the manual incorrect?

Actually both are used indifferently : it's a cone if you look at it in 3D, but if you look at it on a ground track basis, it's a circle. You'll find both in different manuals.

[bradleyjs]

Roger that and thanks for the clarification.

[Pocci]

Counting peas here, but if you project the flight path along a cone to the earth you not get a circle, you get a spiral.
I guess original it was planned to be a cone and the paths like printed in the manual.
When you look at the horizontal situation display you see a circle.
The real flightpath might be something in between and the whole thing purely academic.

[bradleyjs]

Yeah I undstand.. just wondering if the the terminology is incorrect between the  Cmdr's Reference and what NASA calls it. Personally, I prefer "Cone" vs "Circle" because it does seem to make more sense.

[Nephi]

In fact it's even more complicated if we want to get deeper :
1) first Pocci's completely right about the projection : the ground track of a descending pattern alongside a cone would be a portion of a spiral

BUT... (because there's a but)

2) in fact there are not two but THREE origins : the first documents mentionning the HAC show for some of them the cone... but some of them show a cylinder... and the projection of a cylinder is indeed a circle !

So there are in fact THREE HACs : Heading Alignment Circle/Cone/Cylinder !

(although cylinder is not anymore in the official terminology of NASA)

3) and the HORIZ SIT display that we all know well shows a circle which has a changing radius, which is then a portion of a spiral.

If you have a look at the DPS dictionnary for example (go to page 3-66) they also mention a "Heading Alignment CIRCLE" there.

[bradleyjs]

Very interesting... hope I didn't open a can of worms here 

Gotta jist love the technical stuff don't we! So, why aren't we all astronauts? We should be 

[HMSEndeavorreborn]

Welcome home Atlantis. God speed Hubble. Was great to see Hubble back in a shuttle again.

[gablau]

Honestly, my best guess will be an Edwards landing... the weather at KSC has been too unstable because of the severe low pressure we've had for the last 5 days... Nut let's keep our fingers crossed.

As I understand the situation, they only have enough "reserves" (oxygen, etc) to last them till tomorrow and will have to deorbit regardless.

Question: what are the astronauts doing when there is a landing postponement for a day or two? Any scheduled event is unlikely, since if no weather problem, they should have landed without spending and extra day or two in space. I assume that there are no "backup scheduled events, if there is an extra day or two". Are they just sitting there, talking to each other, or play some games, or what? Anyone knows for a fact?

Besides being curious, there is a reason I am asking this question. Once I get an answer, I will reveal the reason.

[uri_ba]

I guess they unpack a deck of cards or something

BTW - considering Backgammon is a standard military passtime here.. has someone came up with a way to roll dice in space?

[Nephi]

I know that at some point, Mass and Scooter were talking about poker but appart from that...

[Nephi]

Something I read on mass's twitter blog that gives a bit of an answer :
"Could not land for 2 days so spent most time looking out windows - this was a gift - listening to music looking at Earth and stars for hours"

[bradleyjs]

Yeah, I was thinking the same thing the other day. And went and read up on  Astro_Mike's twitter and as Nephi said that apparently is what he/they were doing... just relaxing and taking it easy...

I did read or hear that Scooter was practicing his landings on a laptop -- I would have done the same.

[Pocci]

Before they started their last sleep cycle, someone on NASA TV said thy were watching DVD.

[spaceboy7441]

I strongly encourage everyone to checkout this amazing video. It is even better than their last!

http://forum.nasaspaceflight.com/index.php?topic=17237.msg412128;boardseen#new

[schmidtrock]

I strongly encourage everyone to checkout this amazing video. It is even better than their last!

http://forum.nasaspaceflight.com/index.php?topic=17237.msg412128;boardseen#new

Huzzah!! Thanks for the link!