Soyuz relocation -- why, exactly?

Most stories quote the NASA assertion, "The Soyuz relocation cleared the
Pirs Docking Compartment, which doubles as an airlock, for spacewalks now
scheduled for January and March."

But haven't they already done an EVA from Pirs with the Soyuz in place on
Pirs, like, on the last Expedition?

Was this a requirement, or a desirement? And was it really connected with
the EVAs, or with the next Soyuz docking?

"Jim Oberg" wrote in message
...


Most stories quote the NASA assertion, "The Soyuz relocation cleared the
Pirs Docking Compartment, which doubles as an airlock, for spacewalks now
scheduled for January and March."

But haven't they already done an EVA from Pirs with the Soyuz in place on
Pirs, like, on the last Expedition?

Was this a requirement, or a desirement? And was it really connected with
the EVAs, or with the next Soyuz docking?

I was wondering about this myself, since the drawings I've seen make it look
like there is a large hatch on the side of Pirs, which should make EVA's
possible even with a Soyuz attached to its docking port:

http://www.aerospace-technology.com/.../iss/iss5.html

Perhaps this has to do with contingencies like not being able to close the
hatch on Pirs. If your one and only Soyuz is attached to Pirs when this
happens, would it be possible to enter the Soyuz orbital module while still
wearing Russian EVA suits?

Jeff
--
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"John Wilcock" wrote in message
...
Jeff Findley a écrit :
Perhaps this has to do with contingencies like not being able to close
the
hatch on Pirs. If your one and only Soyuz is attached to Pirs when this
happens, would it be possible to enter the Soyuz orbital module while
still
wearing Russian EVA suits?

ISTR they tested Orlan access to Soyuz recently (during Exp. 9?) and
found it possible but difficult.

If this is the only issue, it's more of a desirement than a requirement that
the Soyuz not be docked to Pirs during an EVA which is being conducted from
Pirs.

Jeff
--
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Jim Oberg wrote:
Most stories quote the NASA assertion, "The Soyuz relocation cleared the
Pirs Docking Compartment, which doubles as an airlock, for spacewalks now
scheduled for January and March."

But haven't they already done an EVA from Pirs with the Soyuz in place on
Pirs, like, on the last Expedition?

Was this a requirement, or a desirement? And was it really connected with
the EVAs, or with the next Soyuz docking?

On reflection, it does seem unnecessary for a two man crew. For a three
man crew, it's clearly necessary: it allows the non-EVA crewmember to
work in the station, operate the SSRMS, etc, while having a clear route
to the Soyuz in an emergency. Leaving the Soyuz at Pirs would confine
them to the Soyuz.

But that isn't a constraint with a two-man crew, so it does appear
unnecessary.

--Chris

Chris Bennetts wrote:
But that isn't a constraint with a two-man crew, so it does appear
unnecessary.

If the plans were developped at a time when shuttle was expected back at
station in March with crew augment back to 3 in march, then it was wise to
move the soyuz now while they are less busy.

One also has to take a long term look. There may be clearance issues further
on down the line with regards to shuttle and soyuz schedules where it would be
preferable for the zarya/Pirs cycle to have rotated to have a soyus at Pirs
during a certain Shuttle flight.

"John Wilcock" wrote in message ...

ISTR they tested Orlan access to Soyuz recently (during Exp. 9?) and
found it possible but difficult.


What exactly does this mean?

This clearly represents transfer *within* the pressurized Pirs/Soyuz.





"John Wilcock" wrote in message ...
Explorer8939 a écrit :
"John Wilcock" wrote in message ...


ISTR they tested Orlan access to Soyuz recently (during Exp. 9?) and
found it possible but difficult.



What exactly does this mean?

See http://www.spaceref.com/news/viewsr.html?pid=11039
NASA Space Station On-Orbit Status 18 Nov 2003

Today's crew activities centered on the Russian Orlan IVA training run,
involving a test of retreating, in pressurized spacesuits, from the DC-1
airlock to the Soyuz CRV (crew return vehicle) docked to the DC-1
"Pirs". The exercise was to demonstrate, for the very first time, the
crew's ability to access the Soyuz Orbital Module (BO) in the event of a
contingency during or after the two-man EVA planned for early next year
(there have been no ground sims of this maneuver in the Russian Hydrolab).

Both spacesuits and their ancillary systems were assembled and checked
out properly. But after a preliminary fit check of an inflated Orlan
suit pushed by the crew through the DC1-to-BO hatch last night indicated
marginal clearance, TsUP/Moscow changed the training procedure by having
only FE Kaleri suit up. As it appeared on the downlinked video, his
transfer to the Soyuz BO module through the tight hatchway in the
pressurized Orlan seemed to require active pushing by CDR Foale, himself
remaining unsuited. Russian specialists are now assessing the test and
are expected to develop conclusions and further plans, which could
include a relocation of the Soyuz to the roomier FGB nadir hatch.


John.

(Explorer8939) wrote:

This clearly represents transfer *within* the pressurized Pirs/Soyuz.

So? The suit won't grow smaller. or easier to move around in, nor the
hatch larger, if there was no pressure.

D.
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Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

"John Wilcock" wrote in message
...
As it appeared on the downlinked video, his
transfer to the Soyuz BO module through the tight hatchway in the
pressurized Orlan seemed to require active pushing by CDR Foale, himself
remaining unsuited. Russian specialists are now assessing the test and
are expected to develop conclusions and further plans, which could
include a relocation of the Soyuz to the roomier FGB nadir hatch.

This indicates that there is a good reason to relocate the Soyuz before an
EVA, even with a two man crew. However, I'm not sure why the SP&D hatch on
FGB nadir would be any "roomier" than the SP&D hatch on Pirs.

Jeff
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"Explorer8939" wrote in message
om...
This clearly represents transfer *within* the pressurized Pirs/Soyuz.

I'm sure they pressurized the Orlan suit to the proper gauge pressure to
better test what would happen if they had to do this in vacuum. Note that
this is a standard thing to do for a suit leak check.

Jeff
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