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#1380
by
DaveS
on 21 Oct, 2008 11:30
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I think AOA here should really be AoA or Angle of Attack also called alpha. I think the original poster wants to the know the alpha vs time during the ascent.
And those can be found in the Ascent checklists for the various missions under Cue Cards.
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#1381
by
Jim
on 21 Oct, 2008 11:44
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Duh, silly me
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#1382
by
mkirk
on 21 Oct, 2008 12:36
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I think AOA here should really be AoA or Angle of Attack also called alpha. I think the original poster wants to the know the alpha vs time during the ascent.
And those can be found in the Ascent checklists for the various missions under Cue Cards.
Actually that is THETA on the Ascent ADI Cue Card which is pitch and is not quite the same as Alpha (angle of attack). However, Alpha is listed on the Entry Cue Card.
As for the original question from Christra1, if you clarify which AOA you are talking about one of us can probably get that info.
Mark Kirkman
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#1383
by
christra1
on 21 Oct, 2008 13:22
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I think AOA here should really be AoA or Angle of Attack also called alpha. I think the original poster wants to the know the alpha vs time during the ascent.
And those can be found in the Ascent checklists for the various missions under Cue Cards.
Actually that is THETA on the Ascent ADI Cue Card which is pitch and is not quite the same as Alpha (angle of attack). However, Alpha is listed on the Entry Cue Card.
As for the original question from Christra1, if you clarify which AOA you are talking about one of us can probably get that info.
Mark Kirkman
Thanks for your replies. I am talking about the angle of attack. I know that any corrections for the ascent flight path are done by gimbaling the SRB nozzles (first stage) or SSME nozzles (second stage). That should lead to variations of the AoA. Maybe there is a diagram somewhere that shows it. The abscissa don't has to be time. It can be altitude or velocity. I just want to see the variations in an average ascent.
Rainer
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#1384
by
ChrisC
on 23 Oct, 2008 19:20
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Hi guys -
This should be any easy question for one of you, and actually applies to Soyuz and Progress as well. Can you explain why it takes 2-3 days for the shuttle to reach ISS? I realize that it needs to go through several apogee / perigee burns to circularize the orbit and line up with ISS. But I can't imagine that would take more than a half dozen orbits, and that means it should be there on the same day.
Are there constraints besides orbital mechanics (e.g. transitioning the spacecraft from launch ops to orbital ops) that require the 2 days?
Wishing I'd taken that orbital mechanics course when I was getting my aerospace engineering degree ...
- Chris
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#1385
by
psloss
on 23 Oct, 2008 19:30
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#1386
by
ChrisC
on 23 Oct, 2008 19:50
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It's a frequently asked question...here's a post from Jorge a few years back:
http://forum.nasaspaceflight.com/index.php?topic=4273.msg66595#msg66595
Ah yes, good stuff there, I'd read that before a while back when I asked about low phase and high phase. But the fact that they can only do so much phase catchup is what hadn't sunk in. Quoting from Jorge:
"Since the phasing rate is proportional to the orbit delta-height, for a given ISS orbit height there is a limit to how much phasing the shuttle can accomplish in one day. This is because the shuttle must remain above a minimum height (called "Safe HP", 85 n.mi) in order to stay in orbit."
Plus they always catch up "low" instead of "high" so as not to waste energy. He goes on to mention 3 more secondary reasons for a FD 3 rendezvous, but confirms that:
"... it wouldn't be accurate to say that the shuttle's complexity is the main reason for flight day 3 rendezvous - it's primarily the orbital mechanics and timeline standardization. It is interesting to note that the Russians independently came up with the same answer for the same reasons and always perform Soyuz rendezvous on flight day 3 as well, even though Soyuz is much simpler than the shuttle."
Thanks again!
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#1387
by
ChrisGebhardt
on 23 Oct, 2008 21:49
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Hi guys -
This should be any easy question for one of you, and actually applies to Soyuz and Progress as well. Can you explain why it takes 2-3 days for the shuttle to reach ISS? I realize that it needs to go through several apogee / perigee burns to circularize the orbit and line up with ISS. But I can't imagine that would take more than a half dozen orbits, and that means it should be there on the same day.
Are there constraints besides orbital mechanics (e.g. transitioning the spacecraft from launch ops to orbital ops) that require the 2 days?
Wishing I'd taken that orbital mechanics course when I was getting my aerospace engineering degree ...
- Chris
Don't forget that you also have crew constraints (i.e. sleep) as well as the OBSS TPS inspections that need to be done prior to docking.
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#1388
by
Eerie
on 25 Oct, 2008 20:59
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After the Columbia disaster, why wasn`t paint on the external tank, like in STS-1 or STS-2, implemented again?
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#1389
by
Jim
on 25 Oct, 2008 21:01
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After the Columbia disaster, why wasn`t paint on the external tank, like in STS-1 or STS-2, implemented again?
weight and it doesn't prevent shedding
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#1390
by
ChrisGebhardt
on 25 Oct, 2008 21:06
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After the Columbia disaster, why wasn`t paint on the external tank, like in STS-1 or STS-2, implemented again?
weight and it doesn't prevent shedding
I believe the paint even makes shedding worse in that the extra weight of the paint on any foam that does liberate creates heavier projectiles in the slipstream. Case in point, I remember reading/hearing a comment from John Young that during STS-1 he and Crippen observed multiple paint flecks embedded in Columbia's windows after ascent.
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#1391
by
Eerie
on 25 Oct, 2008 21:16
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I see...
Were any alternatives to foam considered? Something that would eliminate shedding altogether? Or is it impossible?
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#1392
by
Jim
on 25 Oct, 2008 21:41
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Either use the same foam or stop the program because it would be a science project to find another insulation.
Atlas and Delta use the same foam.
The issue isn't that the foam sheds.
The issue is one of the following:
A. Not designing the orbiter with robust TPS so that it can survive a known environment (debris shedding)
or
B. Expecting to design the ET to eliminate debris shedding. (impossible because every launch vehicle sheds debris)
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#1393
by
shuttlefan
on 25 Oct, 2008 23:56
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Remember before STS-121, when the two top safety officials at NASA were no-go for launch due to the ice/frost ramps on the ET? Were they also no-go before the subsequent launches that still had the ice/frost ramps on the tank?
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#1394
by
I14R10
on 30 Oct, 2008 19:47
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I tried to search but i didn't find anything about this - what holds space shuttle from falling from MLP on it's way to Launch Pad?
(Sorry if someone asked this before)
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#1395
by
Ronsmytheiii
on 30 Oct, 2008 19:50
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I tried to search but i didn't find anything about this - what holds space shuttle from falling from MLP on it's way to Launch Pad?
(Sorry if someone asked this before)
Very large bolts on the SRB's, which are blown before SRB ignition.
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#1396
by
jeff2space
on 05 Nov, 2008 20:41
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Not sure if this is a Shuttle or ISS question but: What exactly is the conflict of docking a Progress to ISS while the Shuttle is docked? I know the SSP is strongly against it.
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#1397
by
Jim
on 05 Nov, 2008 20:50
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Not sure if this is a Shuttle or ISS question but: What exactly is the conflict of docking a Progress to ISS while the Shuttle is docked? I know the SSP is strongly against it.
risk of another Mir type collision
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#1398
by
TJL
on 05 Nov, 2008 21:41
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Jim..wasn't there also thruster firing concerns from Progress?
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#1399
by
Jorge
on 05 Nov, 2008 22:45
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Jim..wasn't there also thruster firing concerns from Progress?
Yes, and RFI concerns from Kurs.