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#20
by
Danderman
on 29 Sep, 2009 01:31
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Where did the concept of putting Pirs into an empty payload bay transmogrify into somehow needing to fly an extra mission simply to return Pirs?
And why would it take 3 years to return Pirs?
Let's say that the current manifest is extended out until 2012 or so. Aren't there missions at the tail end of the manifest that will return with at least partially empty payload bays?
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#21
by
rdale
on 29 Sep, 2009 02:06
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If it's too large to fit in the payload bay, does it matter which missions have empty bays on the way home?
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#22
by
hop
on 29 Sep, 2009 02:08
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The numbers that I came up with also suggest that the Pirs compartment has too large a diameter to fit in the payload bay.
I don't see how. Aside from the Strela and a couple other removable appendages it's only slightly fatter than a Soyuz and Progress (<3 meter diameter) See
http://spaceflight.nasa.gov/gallery/images/station/pirs/hires/jsc2001e26682.jpgAnyway, even if you are right, that's doesn't mean it's impossible, you just convert one of the orbiters into a wide body special... STS Super Guppy
^ approximately as realistic as the rest of the plan.
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#23
by
Danderman
on 29 Sep, 2009 05:17
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If it's too large to fit in the payload bay, does it matter which missions have empty bays on the way home?
Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
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#24
by
Danderman
on 29 Sep, 2009 05:22
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The numbers that I came up with also suggest that the Pirs compartment has too large a diameter to fit in the payload bay.
You ARE kidding, aren't you? With the male docking adapter removed, Pirs could fit in the Shuttle payload bay sideways. Otherwise, the max diameter of Pirs is 2.55 meters, and with judicial placement, you could put two of them side by side in the payload bay.
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#25
by
Danderman
on 29 Sep, 2009 05:25
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#26
by
Skyrocket
on 29 Sep, 2009 09:41
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The Mir docking module was equipped for a mounting in the Shuttle cargo bay, Pirs is not - i.e. Pirs can not be put into an empty space, because it can not be fixated in the cargo bay.
It would require a mounting cradle, which would occupy space and mass on the way up, so it would be a very bad deal to sacrifice upmass to bring back an old module.
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#27
by
Zipi
on 29 Sep, 2009 10:50
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Shuttle landing is pretty smooth, is it? At least I have heard that it is more or less comparable to normal commercial aircraft landing.
If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay? Of course it would move and shake more or (hopefully) less during the landing, but by this way it won't require that much upmass penalties... And of course this would be pretty ugly way to treat space hardware, but might do the trick.
This is my 10 cents worth for this discussion... I know NASA wouldn't return Pirs like this because of safety issues etc. but at least I have given my thoughts.
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#28
by
Jim
on 29 Sep, 2009 11:00
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1. And why would it take 3 years to return Pirs?
2. Let's say that the current manifest is extended out until 2012 or so. Aren't there missions at the tail end of the manifest that will return with at least partially empty payload bays?
1. to build the cradle
2. No, because there are no more construction missions. The remaining missions are resupply which bring up and down the same hardware. There is no empty payload bays. Because the empty cradle going up will negate bringing up hardware like MPLM
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#29
by
Jim
on 29 Sep, 2009 11:03
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If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay?
The payload bay is not a container (it does not have rigid surfaces) , it is an enclosed mounting frame, and hence cargo can not rest on the bottom and be tied down
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#30
by
Jim
on 29 Sep, 2009 11:05
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Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
Here is a hint, what else was in the payload bay with it
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#31
by
DaveS
on 29 Sep, 2009 13:03
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Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
Here is a hint, what else was in the payload bay with it
A SpaceLAB module, along with the External Airlock/ODS. And let's not forget that Atlantis still had her original internal airlock as well at the time of the Shuttle/Mir missions. The first OV-104 mission to fly without the internal airlock was STS-101 in May 2000.
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#32
by
psloss
on 29 Sep, 2009 13:27
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Here is a hint, what else was in the payload bay with it
A SpaceLAB module, along with the External Airlock/ODS. And let's not forget that Atlantis still had her original internal airlock as well at the time of the Shuttle/Mir missions. The first OV-104 mission to fly without the internal airlock was STS-101 in May 2000.
No Spacelab or Spacehab on STS-74. Besides the external airlock/ODS, the Docking Module flew in an otherwise empty payload bay.
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#33
by
Danderman
on 29 Sep, 2009 15:01
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If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay?
The payload bay is not a container (it does not have rigid surfaces) , it is an enclosed mounting frame, and hence cargo can not rest on the bottom and be tied down
The question is how to attach trunnion pins and a keel to Pirs.
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#34
by
Danderman
on 29 Sep, 2009 15:02
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Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
Here is a hint, what else was in the payload bay with it
What else was in the payload bay with Shuttle Mir Docking Module?
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#35
by
Chandonn
on 29 Sep, 2009 15:03
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If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay? Of course it would move and shake more or (hopefully) less during the landing, but by this way it won't require that much upmass penalties... And of course this would be pretty ugly way to treat space hardware, but might do the trick.
Surely you're not serious! A module sliding all over the payload bay can do all kinds of damage to every single system needed for re-entry and landing! You're talking about a sizeable piece of free-flying hardware that can detroy the APUs, or smash into the cabin from behind. I don't think there would be enough lucky rabbits feet to keep that landing from being a bad day.
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#36
by
Danderman
on 29 Sep, 2009 15:04
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The Mir docking module was equipped for a mounting in the Shuttle cargo bay, Pirs is not - i.e. Pirs can not be put into an empty space, because it can not be fixated in the cargo bay.
It would require a mounting cradle, which would occupy space and mass on the way up, so it would be a very bad deal to sacrifice upmass to bring back an old module.
The alternative would be to affix trunnion pins and a keel to Pirs.
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#37
by
bobthemonkey
on 29 Sep, 2009 15:09
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And how exactly do you propose doing that? Where are the suitable attach points?
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#38
by
Jim
on 29 Sep, 2009 16:07
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The Mir docking module was equipped for a mounting in the Shuttle cargo bay, Pirs is not - i.e. Pirs can not be put into an empty space, because it can not be fixated in the cargo bay.
It would require a mounting cradle, which would occupy space and mass on the way up, so it would be a very bad deal to sacrifice upmass to bring back an old module.
The alternative would be to affix trunnion pins and a keel to Pirs.
That is the way to affix trunnion pins and a keel to Pirs. Via a cradle. Directly attaching anything to PIRS is not viable.
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#39
by
Jim
on 29 Sep, 2009 16:08
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What else was in the payload bay with Shuttle Mir Docking Module?
nothing. That is my point
