|
Science Forum Index » Space - Shuttle Forum » Undocking question
Page 1 of 1
|
| Author |
Message |
| John Doe |
 Posted: Tue Mar 25, 2008 10:52 am |
|
|
|
Guest
|
When the shuttle undocks from PMA2, springs push it off from PMA2.
(according to NASA TV commentator).
Unless the docking collar happens to be at the centre of gravity/mass of
the shuttle, wouldn't that push put the shuttle into a slow rotation ?
I take it they use vernier thrusters to compensate and give the shuttle
a nice trajectory away from station that retains same attitude ? How
soon after the undocking do they do this ? Is this done "by the seat of
their pants", or do they have precise instrumentation to fire the right
thrusters for the precise amount of time needed ? |
|
|
| Back to top |
|
| Guest |
| Posted: Tue Mar 25, 2008 10:52 am |
|
|
|
|
On Mar 25, 11:52 am, John Doe <j...@doe.org> wrote:
Quote: When the shuttle undocks from PMA2, springs push it off from PMA2.
(according to NASA TV commentator).
Unless the docking collar happens to be at the centre of gravity/mass of
the shuttle, wouldn't that push put the shuttle into a slow rotation ?
I take it they use vernier thrusters to compensate and give the shuttle
a nice trajectory away from station that retains same attitude ? How
soon after the undocking do they do this ? Is this done "by the seat of
their pants", or do they have precise instrumentation to fire the right
thrusters for the precise amount of time needed ?
There is an attitude hold function as part of the autopilot |
|
|
| Back to top |
|
| snidely |
| Posted: Wed Mar 26, 2008 9:55 am |
|
|
|
Guest
|
On Mar 25, 10:28 am, charliexmur...@yahoo.com wrote:
Quote: There is an attitude hold function as part of the autopilot
And "shuttle is commanding the stack" in the period before un-capture.
At one point, while waiting for Beta Gimble Assemblies to latch, I
heard capcom tell Dom that "you have 2 hours prox left". Which leads
to my question -- is the limit on time set by the attitude control
requirements, or by some expendable?
(Remember when hatch closing was the night before?)
Thanks!
/dps |
|
|
| Back to top |
|
| Darren Dunham |
| Posted: Wed Mar 26, 2008 3:12 pm |
|
|
|
Guest
|
snidely <Snidely.too@gmail.com> wrote:
Quote: (Remember when hatch closing was the night before?)
Hatch closing could be delayed for this mission because of the items
involving the OBSS that had to be done before undock. So the undock day
wasn't as busy.
--
Darren Dunham ddunham@taos.com
Senior Technical Consultant TAOS http://www.taos.com/
Got some Dr Pepper? San Francisco, CA bay area
< This line left intentionally blank to confuse you. > |
|
|
| Back to top |
|
| snidely |
| Posted: Fri Apr 04, 2008 7:25 pm |
|
|
|
Guest
|
On Mar 26, 1:12 pm, ddun...@taos.com (Darren Dunham) wrote:
Quote: snidely <Snidely....@gmail.com> wrote:
(Remember when hatch closing was the night before?)
Hatch closing could be delayed for this mission because of the items
involving the OBSS that had to be done before undock. So the undock day
wasn't as busy.
Okay.
What about the limit to prox ops?
/dps |
|
|
| Back to top |
|
| Jorge R. Frank |
| Posted: Sat Apr 05, 2008 11:27 am |
|
|
|
Guest
|
snidely wrote:
Quote: On Mar 26, 1:12 pm, ddun...@taos.com (Darren Dunham) wrote:
snidely <Snidely....@gmail.com> wrote:
(Remember when hatch closing was the night before?)
Hatch closing could be delayed for this mission because of the items
involving the OBSS that had to be done before undock. So the undock day
wasn't as busy.
Okay.
What about the limit to prox ops?
I don't think that's what CAPCOM said. I heard "two hour prop limit". |
|
|
| Back to top |
|
| snidely |
| Posted: Sat Apr 05, 2008 3:31 pm |
|
|
|
Guest
|
On Apr 5, 9:27 am, "Jorge R. Frank" <jrfr...@ibm-pc.borg> wrote:
Quote:
What about the limit to prox ops?
I don't think that's what CAPCOM said. I heard "two hour prop limit".
So that's how long Shuttle can control the stack? Or does that
include the fly-around budget?
/dps |
|
|
| Back to top |
|
| Jorge R. Frank |
| Posted: Mon Apr 14, 2008 10:31 pm |
|
|
|
Guest
|
snidely wrote:
Quote: On Apr 5, 9:27 am, "Jorge R. Frank" <jrfr...@ibm-pc.borg> wrote:
What about the limit to prox ops?
I don't think that's what CAPCOM said. I heard "two hour prop limit".
So that's how long Shuttle can control the stack? Or does that
include the fly-around budget?
No, it's wrong; I misremembered. I guess CAPCOM must have used the word
"prox" on the A/G loop, but the preceding discussion on the Flight loop
regarded TCS/APDS thermal limits. If the undocking had been delayed much
longer, they would have needed to power them down to give them time to
cool off. |
|
|
| Back to top |
|
| snidely |
| Posted: Wed Apr 16, 2008 4:50 pm |
|
|
|
Guest
|
On Apr 14, 8:31 pm, "Jorge R. Frank" <jrfr...@ibm-pc.borg> wrote:
Quote: snidely wrote:
On Apr 5, 9:27 am, "Jorge R. Frank" <jrfr...@ibm-pc.borg> wrote:
What about the limit to prox ops?
I don't think that's what CAPCOM said. I heard "two hour prop limit".
So that's how long Shuttle can control the stack? Or does that
include the fly-around budget?
No, it's wrong; I misremembered. I guess CAPCOM must have used the word
"prox" on the A/G loop, but the preceding discussion on the Flight loop
regarded TCS/APDS thermal limits. If the undocking had been delayed much
longer, they would have needed to power them down to give them time to
cool off.
Okay, thanks. That's an interesting view into the practicalities of
operations.
/dps |
|
|
| Back to top |
|
| |
