Power situation in the ISS Russian Segment has degraded

"James Oberg" wrote in message
...
Something to keep an eye on....


SM batteries: Battery #4 is disconnected (failed 6/16); battery #7
is
in "Cycle" mode; all other batteries (6) are in "Partial Charge" mode.
Batteries #1, #2 and #3 showing degraded capacity. FGB batteries: Battery
#3 is offline; all other batteries (5) are in "Partial Charge" mode.


Good grief - are these nightmare things to change out? Chance to whack them
on the next progress perhaps?

Doug

"Doug Ellison" writes:
Good grief - are these nightmare things to change out? Chance to whack them
on the next progress perhaps?

The Russians have quite a bit of experience with changing these sorts
of batteries in orbit. The problem is that these batteries are big
and heavy. With the shuttle grounded, there is a bit of an uplift
problem right now.

Jeff
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On Thu, 3 Jul 2003 13:30:00 -0400, "Rick C" wrote:
"jeff findley" wrote in message
.. .
"Doug Ellison" writes:
Good grief - are these nightmare things to change out? Chance to whack
them
on the next progress perhaps?

The Russians have quite a bit of experience with changing these sorts
of batteries in orbit. The problem is that these batteries are big
and heavy. With the shuttle grounded, there is a bit of an uplift
problem right now.

Sounds like a bit too much experience. Hope they're researching more
reliable batteries. Maybe the folks doing off-grid solar homes could help
out with some suggestions.

Or talk to the phone company about Edison cells. :-)

They last for many decades with proper care. Of course the energy
storage density isn't very good, and the traditional wet cell design
wouldn't work so well in zero G either.

I assume, not having seen it spelled out, that these batteries are sealed
NiCads. They do have a limited cycle life.

Gary

Gary Coffman writes:

On Thu, 3 Jul 2003 13:30:00 -0400, "Rick C" wrote:
"jeff findley" wrote in message
.. .
The Russians have quite a bit of experience with changing these sorts
of batteries in orbit. The problem is that these batteries are big
and heavy. With the shuttle grounded, there is a bit of an uplift
problem right now.

Sounds like a bit too much experience. Hope they're researching more
reliable batteries. Maybe the folks doing off-grid solar homes could help
out with some suggestions.

Or talk to the phone company about Edison cells. :-)

They last for many decades with proper care. Of course the energy
storage density isn't very good, and the traditional wet cell design
wouldn't work so well in zero G either.

I assume, not having seen it spelled out, that these batteries are sealed
NiCads. They do have a limited cycle life.

Please note that the charge/discharge cycle of the batteries on ISS is
one discharge and one charge *per orbit*! At the rate that ISS orbits
the earth, you are really putting the batteries through a tough duty
cycle. Why don't you try that sort of duty cycle on a consumer grade
battery and see how long it lasts?

If you search for "Russian service module batteries" on Yahoo!, you'll
find out that the batteries on the Russian side are nickel-cadmium.
Early on, batteries (and their charging controllers) in both Zarya and
Zvezda had problems and several were replaced.

I can't find a figure for the weight of one of these batteries, but
have found articles that say Zvezda module was launched with just five
of its eight batteries in place, "to save weight". I have a feeling
these things may be "bigger than a breadbox".

Jeff
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On Thu, 03 Jul 2003 13:22:27 GMT, "James Oberg"
wrote:

[Of the eight 800A storage batteries in the SM, one is completely
unusable (#4), and three more units (#1, #2, and #3) are showing reduced
capacity (i.e., inability to fully charge).

The EXP-2 crew (Usachev, Helms, Voss) replaced what would have been 2/3 of the
EXP-7 crew (Malenchenko, Lu) on STS-101/2A.2a (which got split into 2A.2a and
STS-106/2A.2b) in order for them to be able to do battery replacement on the SM
back in 2001. Which batteries did they replace?

I seem to remember something about this being close to their normal lifetime
anyway.

"Rick C" writes:

"jeff findley" wrote in message
...
"Doug Ellison" writes:

Good grief - are these nightmare things to change out? Chance to
whack them on the next progress perhaps?

The Russians have quite a bit of experience with changing these sorts
of batteries in orbit. The problem is that these batteries are big
and heavy. With the shuttle grounded, there is a bit of an uplift
problem right now.

Sounds like a bit too much experience. Hope they're researching more
reliable batteries. Maybe the folks doing off-grid solar homes could help
out with some suggestions.

Not a solution now, but why can some of the battery capacity on ISS
not be replaced with something much more reliable?

I am thinking flywheels. Spin them up when you have excess energy and
used them to generate power when you need it. Of course you would
always use a pair of counter rotating flywheels to keep torque
transferred to the station at zero.

--
Manfred Bartz

Not a solution now, but why can some of the battery capacity on ISS
not be replaced with something much more reliable?


I am thinking flywheels. Spin them up when you have excess energy and

The vibration would kill microgravity research.

Manfred Bartz writes:


Nonsense. There are 4 large flywheels operating on the ISS right now,
the CMGs (control moment gyros).

Actually, only 3 are in operating condition at this time :-(

In news:Hallerb typed:
Nonsense. There are 4 large flywheels operating on the ISS right
now, the CMGs (control moment gyros).

Actually, only 3 are in operating condition at this time :-(

Yeah but were talking of much bigger more powerful ones who speed
will vary a lot over time, putting and taking power as needed.

You can add so much stuff like this that research will be
impossible...

Do you *ever* admit you screwed up when someone calls you on an
error? Obviously you know you were wrong because you snipped your error
out. But just once it would be nice to see just a touch of humility
that you don't have all the answers around here. Sheesh.
--
Mike
__________________________________________________ ______
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On 08 Jul 2003 21:11:39 GMT, (Hallerb) wrote:
Yes but theres a huge difference between power supplying flywhhels and gyros.

Care to elaborate? Both use extremely well balanced masses rotating rapidly
on extremely precise low friction bearings. Both are spun up and down by
electrical fields. The difference as I see it is that the CMG dumps its energy
wastefully when it is being desaturated while a power supplying flywheel
would supply it usefully to a power conditioner.

Perhaps you were expecting them to hard switch loads on and off the flywheel
directly. That would cause a jolt each time a load was picked up or shed. But
give the engineers credit for knowing not to do it that way. In the first place there
would be pairs of counterrotating wheels, with loads applied equally to them,
and second they'd use a power conditioner with soft start and soft stop to switch
the loads on and off the wheels.

Note, I'm not necessarily endorsing flywheels as battery replacements, but you
haven't shown that "vibration" would be show stopper to it.

Gary