msnbc-oberg: Spacewalkers cope with phantom menace

Spacewalkers cope with phantom menace

How a weak jet of water and a flawed contingency plan led to a
communications breakdown in orbit

http://www.msnbc.msn.com/id/5592615



By James Oberg, NBC News space analyst // Special to MSNBC

Updated: 5:19 p.m. ET Aug. 3, 2004



During an otherwise-routine spacewalk Tuesday, the international space
station's astronauts were faced with a half-hour loss of communications
when the station drifted out of precise orientation. The cause of these
anomalies was a previously known issue with the duo's Russian spacesuits,
according to internal NASA documents obtained by MSNBC.com.



Moreover, a corrective procedure that had been developed in recent weeks in
anticipation of exactly such a problem turned out to be flawed, NASA sources
said on condition of anonymity.



Various explanations have been given for Tuesday's glitch: Some news
accounts indicated that the station's stabilizing gyroscopes were overloaded
by the crew's strenuous work replacing equipment at the Russian end of the
station. In Moscow, spokesmen for Russia's space agency blamed American
stabilizers and the rough handling of the station by the two men in orbit,
NASA astronaut Mike Fincke and Russian cosmonaut Gennady Padalka.



But according to the NASA documents, a U.S.-Russian team determined last
month that the station was likely to be forced out of proper orientation by
a feature of the Russian spacesuits the men were wearing. Similar drifts had
been seen on earlier spacewalks, and will be again, the team concluded.

On Tue, 03 Aug 2004 14:38:48 -0700, Jim Oberg wrote:

Spacewalkers cope with phantom menace

How a weak jet of water and a flawed contingency plan led to a
communications breakdown in orbit

So when are they going to stop ****ing around up there?

--Damon

So when are they going to stop ****ing around up there?

--Damon

One of these ooops is going to lead to a lost crew member or entire station
sooner or later
HAVE A GREAT DAY!

"Jim Oberg" wrote in message
...
But according to the NASA documents, a U.S.-Russian team determined last
month that the station was likely to be forced out of proper orientation
by
a feature of the Russian spacesuits the men were wearing. Similar drifts
had
been seen on earlier spacewalks, and will be again, the team concluded.

I suspected the cooling system on the suits, then I took a look at the full
article and saw I was right. Another informative, yet easy to read,
article.

It sounds like it's time to design the suit to vent the water in a symmetric
fashion in order to null out the net force.

Jeff
--
Remove icky phrase from email address to get a valid address.

"Jim Oberg" wrote in message ...
Spacewalkers cope with phantom menace

How a weak jet of water and a flawed contingency plan led to a
communications breakdown in orbit

http://www.msnbc.msn.com/id/5592615



By James Oberg, NBC News space analyst // Special to MSNBC

Updated: 5:19 p.m. ET Aug. 3, 2004



During an otherwise-routine spacewalk Tuesday, the international space
station's astronauts were faced with a half-hour loss of communications
when the station drifted out of precise orientation. The cause of these
anomalies was a previously known issue with the duo's Russian spacesuits,
according to internal NASA documents obtained by MSNBC.com.



Moreover, a corrective procedure that had been developed in recent weeks in
anticipation of exactly such a problem turned out to be flawed, NASA sources
said on condition of anonymity.



Various explanations have been given for Tuesday's glitch: Some news
accounts indicated that the station's stabilizing gyroscopes were overloaded
by the crew's strenuous work replacing equipment at the Russian end of the
station. In Moscow, spokesmen for Russia's space agency blamed American
stabilizers and the rough handling of the station by the two men in orbit,
NASA astronaut Mike Fincke and Russian cosmonaut Gennady Padalka.



But according to the NASA documents, a U.S.-Russian team determined last
month that the station was likely to be forced out of proper orientation by
a feature of the Russian spacesuits the men were wearing. Similar drifts had
been seen on earlier spacewalks, and will be again, the team concluded.


What a fascinating story. Who would've thunk it? Obviously the
procedures need to be honed and I'm sure this will get a thorough
review and contribute to NASA's knowledgebase.

On the bright side...I suppose now you could theoretically use the
sublimator to fly back to the station if inadvertantly set adrift.
Just aim your backpack and crank up the cooling for thrust!

I wonder if the EMUs produce the same motive force...

-cache!

alt.alien.visitors snipped from reply . . . :-/

In article ,
(cache) wrote:

"Jim Oberg" wrote in message
...
Spacewalkers cope with phantom menace

How a weak jet of water and a flawed contingency plan led to a
communications breakdown in orbit


(snip)


But according to the NASA documents, a U.S.-Russian team determined last
month that the station was likely to be forced out of proper orientation by
a feature of the Russian spacesuits the men were wearing. Similar drifts
had
been seen on earlier spacewalks, and will be again, the team concluded.


(snip)

On the bright side...I suppose now you could theoretically use the
sublimator to fly back to the station if inadvertantly set adrift.
Just aim your backpack and crank up the cooling for thrust!

I wonder if the EMUs produce the same motive force...


And to think, when I was working on the CO2 and H20 vent lines for the
SSF ECLSS, the operations and assembly people ****ed and moaned over the
need for non-propulsive vent fixtures for these lines, loudly
proclaiming that there was no way such low-thrust venting should have
any kind of effect. When the GN&C design people and I whipped out a
back of the envelope integration showing how the vents could saturate
the CMGs in just a couple of days (*), they relented pretty quickly. A
one-time investment of an hour of on-orbit EVA assembly time was deemed
more expedient than hundreds of tons of fuel over the lifetime of the
station . . . ;-)

(*) There were certain scenarios where the effect wasn't so pronounced,
notably just before the PMC milestone with the station core
configuration mostly complete, the truss symmetrical and only
intermittent crew visits, but during any mission prior to that, the
problem was noted to have been serious enough to be concerned with.

--
Herb Schaltegger, B.S., J.D.
"Never underestimate the power of human stupidity."
~ Robert A. Heinlein
http://www.angryherb.net

"Herb Schaltegger" wrote
And to think, when I was working on the CO2 and H20 vent lines for the
SSF ECLSS, the operations and assembly people ****ed and moaned over the
need for non-propulsive vent fixtures for these lines, loudly
proclaiming that there was no way such low-thrust venting should have
any kind of effect. When the GN&C design people and I whipped out a
back of the envelope integration showing how the vents could saturate
the CMGs in just a couple of days (*), they relented pretty quickly. A
one-time investment of an hour of on-orbit EVA assembly time was deemed
more expedient than hundreds of tons of fuel over the lifetime of the
station . . . ;-)

Wonderful context, Herb -- let me quote you on this in a follow-up!

On 2004-08-04, Herb Schaltegger wrote:

And to think, when I was working on the CO2 and H20 vent lines for the
SSF ECLSS, the operations and assembly people ****ed and moaned over the
need for non-propulsive vent fixtures for these lines, loudly
proclaiming that there was no way such low-thrust venting should have
any kind of effect. When the GN&C design people and I whipped out a
back of the envelope integration showing how the vents could saturate
the CMGs in just a couple of days (*), they relented pretty quickly. A
one-time investment of an hour of on-orbit EVA assembly time was deemed
more expedient than hundreds of tons of fuel over the lifetime of the
station . . . ;-)

Herb, how complex are nonpropulsive vents? A discussion elsewhere led to
the prospect of retrofitting them to Orlans, though personally it seems
an excessive amount of effort for little gain.

(In fact - failure-to-understand-environment time - would they even be
plausible for a sublimator?)

A thought for the futu

When the EMUs are in use again (I seem to recall that parts are
currently waiting for replacement), it should in theory be possible to
plan EVAs on the "far reaches" of the station - where sublimation
effects are strongest - to avoid this problem, or is that just optomism
running away? (Admittedly, that doesn't help for the next EVA, but...)

The article mentioned:

"The 'load shed' procedure kicked in, automated by the station's control
computers. With only a two-man station crew, there was no third crew
member inside to override or modify the procedure - and it turned out it
needed to be modified."

What other practical benefit would have been derived from having a
crew-member inside and working - would LOS have been prevented?

--
-Andrew Gray

"Andrew Gray" wrote in message
. ..
On 2004-08-04, Herb Schaltegger
wrote:

And to think, when I was working on the CO2 and H20 vent lines for the
SSF ECLSS, the operations and assembly people ****ed and moaned over the
need for non-propulsive vent fixtures for these lines, loudly
proclaiming that there was no way such low-thrust venting should have
any kind of effect. When the GN&C design people and I whipped out a
back of the envelope integration showing how the vents could saturate
the CMGs in just a couple of days (*), they relented pretty quickly. A
one-time investment of an hour of on-orbit EVA assembly time was deemed
more expedient than hundreds of tons of fuel over the lifetime of the
station . . . ;-)

Herb, how complex are nonpropulsive vents? A discussion elsewhere led to
the prospect of retrofitting them to Orlans, though personally it seems
an excessive amount of effort for little gain.

Forget complex, how does one design one? (I've got one idea, but I'm
curious.)

In article ,
Andrew Gray wrote:

Herb, how complex are nonpropulsive vents? A discussion elsewhere led to
the prospect of retrofitting them to Orlans, though personally it seems
an excessive amount of effort for little gain.

In principle, not complex at all. For gases, a simple tee-fixture is
all that's required. For liquids such as water or urine you generally
need heaters out there, too, to avoid icing and clogs. That requires
power and probably data connections as well (for temperature and/or
current sensors). The issues with regard to using them on SSF (and
hence the U.S. modules of ISS) is that they have to penetrate the
meteoroid/debris shielding and they have to be oriented such that they
don't impinge on anything of importance (surface contamination issues).
To avoid surface contamination, you want them several inches (or more)
off the surface of the debris shielding. In the case of SSF, the extent
to which the vent fixtures had to protrude exceeded the defined,
baseline launch envelope. That meant EVA assembly. At the time, they
were discussing a total EVA assembly time of nearly a thousand hours or
more (!!!) - about 150 EVAs of 4 - 7 hours each was bandied about
informally.

(In fact - failure-to-understand-environment time - would they even be
plausible for a sublimator?)

Sure; the U.S. Carbon Dioxide Removal Assembly essentially sublimates
CO2 out of its molecular sieve beds. You'd just need a housing over the
sublimator and a large-diameter tee-fixture for a vent; it would have to
be a big enough housing and large-enough diameter fixture such that the
local "atmosphere" didn't accumulate enough to interfere with the
sublimation process, of course. The other issue might be a risk of
icing, but I don't know if the water flow rates are high enough to worry
about.

A thought for the futu

When the EMUs are in use again (I seem to recall that parts are
currently waiting for replacement), it should in theory be possible to
plan EVAs on the "far reaches" of the station - where sublimation
effects are strongest - to avoid this problem, or is that just optomism
running away? (Admittedly, that doesn't help for the next EVA, but...)

The further you are from the station center of mass, the greater the
torque.

The article mentioned:

"The 'load shed' procedure kicked in, automated by the station's control
computers. With only a two-man station crew, there was no third crew
member inside to override or modify the procedure - and it turned out it
needed to be modified."

What other practical benefit would have been derived from having a
crew-member inside and working - would LOS have been prevented?

I don't know for the current situation; at least someone would have been
"home" to recognize the issue and take steps to correct or prevent it.

--
Herb Schaltegger, B.S., J.D.
"Never underestimate the power of human stupidity."
~ Robert A. Heinlein
http://www.angryherb.net