Author Topic: General ISS Q&A thread  (Read 879804 times)

Offline eeergo

Re: General ISS Q&A thread
« Reply #800 on: 11/22/2008 11:02 am »
In this article:

http://www.nasaspaceflight.com/2008/11/sts-126-eva-1-major-effort-repair-sarj/

it says that:

"This mission also includes the transfer, installation, and activation of several systems to support six person crew, such as ... a food refrigerator..."

But that refrigerator is elsewhere described as a "lab refrigerator". Is the ISS really getting a food refrigerator?

It is a refrigerator  designed for ISS lab use being used as a food refrigerator

They're carrying two refrigerators: GLACIER, for scientific purposes, is going to be installed in MELFI. Apart from that, MERLIN (once intended as a scientific freezer, as Jim says) is the one now intended for food&drink cooling.
-DaviD-

Offline erioladastra

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Re: General ISS Q&A thread
« Reply #801 on: 11/22/2008 11:13 pm »
I understand that most glove damage in EVA happen during moving around? Is that true? If so, why astronauts don`t use some overall gloves, chain-mail maybe?

WEll they do.  First, it was not clear what was causing the problem.  And it doesn't look to be external but part of the design combined with external.  Secondly, the gloves are already very hard to move and tire the hands.  Putting more on make it harder and actually more dangerous (you don't want them to get so tired they let go while translating).  So when the problem first arose, they used some over gloves but the crew hated them.  Since they have added turtle skin to the worst areas and that si what we are using now.

Offline Wicky

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Re: General ISS Q&A thread
« Reply #802 on: 11/22/2008 11:58 pm »
Hi

I've searched for "knocking noise" "banging sound" without a relevant result

When I watch NASA TV for the EVAs, the audio between the astronauts and controllers carries a background banging noise, like someone banging a barrel?? 

Very odd...  ???


Offline robertross

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Re: General ISS Q&A thread
« Reply #803 on: 11/23/2008 12:00 am »
Hi

I've searched for "knocking noise" "banging sound" without a relevant result

When I watch NASA TV for the EVAs, the audio between the astronauts and controllers carries a background banging noise, like someone banging a barrel?? 

Very odd...  ???



You sure it wasn't their mics coming on when they breathe?? The mics are voice activated, and if they breathe hard enough it activates transmission.

Offline Wicky

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Re: General ISS Q&A thread
« Reply #804 on: 11/23/2008 12:42 am »


Found this clip from a previous mission which has the percussive knocking on the audio at 0.27 0.28 then at 0.50 0.51

 / 2.48 2.51-2-52 and at several other points throughout the clip


 ???


Offline TJL

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Re: General ISS Q&A thread
« Reply #805 on: 11/23/2008 09:33 pm »
Though it rarely occurs, I often wondered which flight patch an ISS crew member wears on their suit when they perform an EVA with the docked shuttle crew?
As an example, Clay Anderson, member of ISS 15 (and STS 117) took part in an EVA with the STS 118 crew. I can't seem to locate any photos that could answer this question.
Thank you.

Offline henryhallam

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Re: General ISS Q&A thread
« Reply #806 on: 11/24/2008 11:01 pm »
Shuttle and American spacewalks have SAFER as a backup if an astronaut's tether comes loose, but as I understand it there is no similar jetpack used on the Russian-side EVAs.   Is there any emergency procedure if an astronaut in an Orlan suit loses his/her tether and drifts away?   Would an attempt be made to use Soyuz to rendezvous? (Assuming there is no orbiter available)

Offline YesRushGen

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Re: General ISS Q&A thread
« Reply #807 on: 11/25/2008 02:39 pm »
Shuttle and American spacewalks have SAFER as a backup if an astronaut's tether comes loose, but as I understand it there is no similar jetpack used on the Russian-side EVAs.   Is there any emergency procedure if an astronaut in an Orlan suit loses his/her tether and drifts away?

I've wondered about that too, thanks for asking. I'm sure someone with the answer will chime in.

A speculative thought: Being that the "stranded" EVA person is in their own independant orbit, could the ISS conceivably alter it's orbit such that there would be a rendezvous with the stranded astronaut? Seems possible in theory at least. Also seems like it would take ultra-precise targeting to prevent the astronaut from running into an undesirable location, like a solar array.

Offline anik

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Re: General ISS Q&A thread
« Reply #808 on: 11/25/2008 03:38 pm »
Shuttle and American spacewalks have SAFER as a backup if an astronaut's tether comes loose, but as I understand it there is no similar jetpack used on the Russian-side EVAs

Many years ago NPP Zvezda enterprise has manufactured three USK jetpacks (analogue of SAFER) for using on Orlan-M/MK spacesuits. But later it was decided not to send them on ISS for now. So, during Russian spacewalks each cosmonaut continues to use two tether.
« Last Edit: 11/25/2008 03:42 pm by anik »

Offline Jorge

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Re: General ISS Q&A thread
« Reply #809 on: 11/25/2008 03:51 pm »
Shuttle and American spacewalks have SAFER as a backup if an astronaut's tether comes loose, but as I understand it there is no similar jetpack used on the Russian-side EVAs.   Is there any emergency procedure if an astronaut in an Orlan suit loses his/her tether and drifts away?

I've wondered about that too, thanks for asking. I'm sure someone with the answer will chime in.

A speculative thought: Being that the "stranded" EVA person is in their own independant orbit, could the ISS conceivably alter it's orbit such that there would be a rendezvous with the stranded astronaut? Seems possible in theory at least. Also seems like it would take ultra-precise targeting to prevent the astronaut from running into an undesirable location, like a solar array.

ISS can only translate in one direction (+X) and so any rendezvous maneuver would require rotating the whole station to point the +X axis in the required direction for the delta-V.

ISS is extremely massive so any rendezvous maneuver requires a very long burn arc.

In short, it is impractical.
JRF

Offline markius

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Re: General ISS Q&A thread
« Reply #810 on: 11/26/2008 06:21 pm »
Hi

I read in one of the STS-126 live threads that once operational, the WRS will actually produce more potable water than the *noughts will consume with the excess being used as a raw material for the new OGA.

Is this correct?
Based on 3 inhabitants of the ISS, by how much does the WRS reduce the need for potable water to transferred from the ground?
Assuming the OGA will do some form of electrolysis, what will the hydrogen be used for?

Thanks in advance
Mark

Offline AnalogMan

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Re: General ISS Q&A thread
« Reply #811 on: 11/26/2008 06:39 pm »
Hi

I read in one of the STS-126 live threads that once operational, the WRS will actually produce more potable water than the *noughts will consume with the excess being used as a raw material for the new OGA.

Is this correct?
Based on 3 inhabitants of the ISS, by how much does the WRS reduce the need for potable water to transferred from the ground?
Assuming the OGA will do some form of electrolysis, what will the hydrogen be used for?

Thanks in advance
Mark

This is what NASA says about the WRS in the STS-126 presskit:

"The WRS is designed to recycle crew member urine and wastewater for reuse as clean water.

Each crew member uses about 3.5 liters (0.9 gallons) of water a day. Enough for 2 liters (0.52 gallons) a day is provided by deliveries from Russian Progress resupply vehicles, ESA’s Jules Verne Automatic Transfer Vehicle and the space shuttles. The remaining 1.5 liters (0.4 gallons) is recovered condensate from the Russian water processor. The two cargo vehicles carry water to the station in onboard supply tanks. The shuttle delivers water produced as a byproduct of the fuel cells that generate its electricity.

The WRS will reduce the amount of water that needs to be delivered to the station for each crew member by 1.3 liters (0.34 gallons) a day, or about 65 percent. Over the course of a year, it will reduce water deliveries to the station for a six‐person crew by 2,850 liters (743 gallons).
"

And on the oxygen generator:

"The heart of the Oxygen Generation Assembly is the cell stack, which electrolyzes, or breaks apart, water provided by the WRS, yielding oxygen and hydrogen as byproducts. The oxygen is delivered to the cabin atmosphere,and the hydrogen is vented overboard."

http://www.nasa.gov/pdf/287211main_sts126_press_kit2.pdf

Offline wjbarnett

Re: General ISS Q&A thread
« Reply #812 on: 11/26/2008 07:07 pm »
Assuming the OGA will do some form of electrolysis, what will the hydrogen be used for?

Thanks in advance
Mark

IIRC (real experts correct me please), the hydrogen is dumped overboard. Can't easily store it, since it's produced as a gas at low pressure, and large quantities would probably increase risk of LOM/LOC. Too bad, as saving H for propellant use could reduce the future costs of leaving LEO (not that ISS's orbit is very efficient for that).
« Last Edit: 11/26/2008 07:17 pm by wjbarnett »
Jack

Offline nacnud

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Re: General ISS Q&A thread
« Reply #813 on: 11/26/2008 07:29 pm »
The only use I could think of for the hydrogen is as propellant would be in the VASIMR that trying to find it's way up there.

Offline rdale

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Re: General ISS Q&A thread
« Reply #814 on: 11/26/2008 07:38 pm »
So is the starboard SARJ in autotrack mode, or is it back to the old style "move only when needed" until a later date?

Offline wjbarnett

Re: General ISS Q&A thread
« Reply #815 on: 11/26/2008 07:54 pm »
So is the starboard SARJ in autotrack mode, or is it back to the old style "move only when needed" until a later date?
Just answered by Holly during FD13 press conference: not in autotrack, pending further engineering analysis (several weeks/months testing to come).
« Last Edit: 11/26/2008 07:55 pm by wjbarnett »
Jack

Offline dmac

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Re: General ISS Q&A thread
« Reply #816 on: 11/26/2008 08:13 pm »
Hi,regards ISS mission control.Do the teams generally do the same
shift times.If not  it must effect their own body clocks/family life.I assume they all live "locally"


Offline Life_Support_32

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Re: General ISS Q&A thread
« Reply #817 on: 11/26/2008 08:30 pm »
Hi,regards ISS mission control.Do the teams generally do the same
shift times.If not  it must effect their own body clocks/family life.I assume they all live "locally"



Flight Controllers generally work the same shift for a week at a time.  It depends on the group, but I know in my group, you can expect to be on-console about one week/month.  Depending on certifications, several of the flight control disciplines can be combined for weekend/night shifts into one of two GEMINI positions to take some of the load off the individual groups.  With the changing station, though, it is becoming very difficult for some of the positions to be combined into a GEMINI (too much work load), so those console positions are being manned for 3 shifts a day (2 per weekend).

As far as how it affects your body, Flight Controllers have learned what it takes them individually to shift to night/early/late, so it generally isn't a problem, once you get shifted.  It is tough having a social life if you're sleeping most of the day and working at night, but you work around it, and you accept it as part of the job.

Offline Life_Support_32

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Re: General ISS Q&A thread
« Reply #818 on: 11/26/2008 08:32 pm »
The only use I could think of for the hydrogen is as propellant would be in the VASIMR that trying to find it's way up there.

One potential use for the Hydrogen is to be merged with CO2 to produce Methane and Water.  The Methane would be dumped overboard and the Water would be sent to the Water Processing Assembly.  There is a piece of hardware that is slated to fly in 2010, but not sure if it will make it up there or not.  That would close the Life Support System loop as much as is planned for ISS.

Offline markius

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Re: General ISS Q&A thread
« Reply #819 on: 11/26/2008 09:53 pm »
The only use I could think of for the hydrogen is as propellant would be in the VASIMR that trying to find it's way up there.

One potential use for the Hydrogen is to be merged with CO2 to produce Methane and Water.  The Methane would be dumped overboard and the Water would be sent to the Water Processing Assembly.

Wow... so the Hydrogen could be used to scrub CO2 from the atmosphere AND produce more water.  How would you merge Hydrogen and CO2?  My first thought was by burning the Hydrogen in a CO2 atmosphere... Can you tell I was always better at physics that chemistry?!

How about for use in a fuel cell similar to those on board the orbiter?  I'm guessing that there's a FC maintenance issue along with the inherent risk of storing hydrogen stated earlier.

Thanks for your replies so far.

Mark

 

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