Author Topic: EVA Q&A  (Read 27968 times)

Offline Danderman

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Offline AJA

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Re: EVA Q&A
« Reply #41 on: 12/21/2013 12:58 pm »
1. Watching this current (Ammonia PM R&R) EVA... I'm wondering...
Why don't they have velcro pads on the outside of their suits... say..on the quadricep area... with corresponding velcro pads near the carabiners/tether hooks? It'll keep all those tools and parts from floating around in front of them...


Or do they already have it?




2. Do they have borescopes on the station? Or even an endoscope? It would've come in handy for something like this. They could peer into the PM and with some fibre-optics, go up to the FCV, and see what the problem was? Especially because the PM's not coming back down anytime soon..


It might be useful in a lot of other EVA cases too.
« Last Edit: 12/21/2013 01:54 pm by AJA »

Offline manboy

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Re: EVA Q&A
« Reply #42 on: 01/18/2014 09:45 pm »
Hello everybody,

I am actually looking for some information on the space suits:
As I am studying the breathing system, I would be glad to have some more knowledge on this.
I know there are different space suits depending on the country, however I don't know if the breathing system is different. If so, I would be happy to know these differences.
Every pieces of advice you got will really help me.
I also need details such as formulas:
(for example :  2(LiOH, H2O) + CO2 ---> LiCo3 + 3H2O)
Any websites about this are welcomed.
What in your opinion could make this breathing system better?

Do you have any ideas on the possible future improvements?

Still concerning the space suit equipments, I needed some information about the pressure system.
First of all, I don’t really know if it works the same way for the different space suits.
The pressure in the space suit is lower than on Earth, is there a consequence on the human using it?
How does it work, how is it possible to lower the pressure in the space suit?
If you have any more information about pressure, such as pressure in space compared to pressure on Earth, or just interesting websites … that will be really helpful

Thanks !

(Please forgive the mistakes I made as English isn't my first language)
Almost all spacesuits have been either American or Russian, in the early 2000s the Chinese started making suits but theirs are heavily derived from Russia's. The pressure at sea-level is 14.7 psi (1,013 hPa) and the air there consists primarily of a mix of Nitrogen (78%), Oxygen (21%) and Argon (1%). Spacesuits typically contain a pure oxygen environment and operate between 3.5 psi to 5.8 psi (241 hPa to 400 hPa). Modern Extra-vehicular activities (EVA), also called spacewalks, typically last a duration of about eight hours.

Beyond that my knowledge on the subject is limited but I think I can point you towards some useful resources (which are unfortunately only available in English).

Books
U.S. Space Gear : Outfitting The Astronaut (English), 1993
Russian Spacesuits (English), 2003
U.S. Spacesuits (English), 2006
Dressing For Altitude (English), 2012

Documents
Discuses some planned advances
Also search for "PLSS" on NTRS and you'll find some relevant info
"Cheese has been sent into space before. But the same cheese has never been sent into space twice." - StephenB

Offline FinnishArmy

Re: EVA Q&A
« Reply #43 on: 06/26/2015 09:06 pm »
Hey! Are the people allowed to just take Space Walks for "fun"?

Offline nadreck

Re: EVA Q&A
« Reply #44 on: 06/26/2015 09:19 pm »
Hey! Are the people allowed to just take Space Walks for "fun"?

No more than they are allowed to launch a spacecraft just for fun. In fact, if you think about it, it is launching a spacecraft. However, they aren't expressly forbidden from having fun when they take Space Walks.

EVA's are very much planned and scheduled, even if it was an emergency response to a problem a team would have put together a plan.
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Offline the_other_Doug

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Re: EVA Q&A
« Reply #45 on: 06/27/2015 12:34 am »
An EVA exposes the extravehicular crewperson to quite a bit higher risk than the crew sitting inside the ISS experience.  You don't just go outside for fun.

All of manned spaceflight is risky, and what they do is based on a risk vs. reward calculation.  The reward to be gained from a given EVA has to be worth the extra risk of putting people out into little human-shaped spacecraft and trusting that no flecks of paint from some old satellite will strike them at several thousand kph in a vulnerable spot (like in the helmet), no leak of the cooling system will threaten to drown them, no vertiginous spacewalker will puke into his helmet and choking to death, no sudden failure of a wrist wring will expose them to vacuum suddenly... etc., etc.

It's not something to be done for kicks.  Especially since, unlike some damnfool risking his life by jumping out of an airplane, or climbing up into an abandoned grain silo (like someone did last night here in Minneapolis, killing himself), etc., losing an EVA crewman on ISS has a much more far-reaching impact.  It would reflect on the entire manned space flight effort around the world, and could conceivably cause the abandonment of the ISS.

It's not safe out there -- not safe enough to do it just for fun.
-Doug  (With my shield, not yet upon it)

Online Bob Shaw

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Re: EVA Q&A
« Reply #46 on: 06/27/2015 01:00 am »
What's the betting that the Russians will allow one of their guests to take a wholly recreational spacewalk, if paid to do so?
 
Having said that, however, most of their 'guests' would be likely to spend their time working during such an EVA, though perhaps not on engineering tasks. And some of the tasks performed by professional astronauts during EVAs have not been exactly, er, professional - look at some of the Russian EVA stunts.

Look back too at the early US EVAs on MIR, and ask what the NASA guys actually did. Taping off controls in the airlock implies a tourist status to me!

And as for a certain Lunar golfer...

Offline nadreck

Re: EVA Q&A
« Reply #47 on: 06/27/2015 01:04 am »
What's the betting that the Russians will allow one of their guests to take a wholly recreational spacewalk, if paid to do so?
 
Having said that, however, most of their 'guests' would be likely to spend their time working during such an EVA, though perhaps not on engineering tasks. And some of the tasks performed by professional astronauts during EVAs have not been exactly, er, professional - look at some of the Russian EVA stunts.

Look back too at the early US EVAs on MIR, and ask what the NASA guys actually did. Taping off controls in the airlock implies a tourist status to me!

And as for a certain Lunar golfer...

Not the same thing, and it would still be planned, probably within an inch of its life. Loosing the tourist is just bad press, doesn't risk the mission. However, the fair price to add on this optional adventure extra to your $60M ISS package is probably another $10M for the suit and the extra training.  BTW if I were the guest I would WANT to do some grunt work on the EVA (as well as some lollygagging)
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Online Bob Shaw

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Re: EVA Q&A
« Reply #48 on: 06/27/2015 01:13 am »
Actually, the Russian attitude towards EVA planning is: 'We trained you, here are the tools, do it' - unlike the step-by-step NASA style. It is entirely within reason that they would say 'We trained you, go float, take pictures, don't interfere'. The Russian way, eventually, is the right way, but even in the meantime would cope easily with a tourist.

Online AnalogMan

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Re: EVA Q&A
« Reply #49 on: 06/27/2015 10:35 am »
For an idea of how well planned US EVAs are see these timelines for EVA 22 and EVA 23:

http://www.nasa.gov/sites/default/files/files/US_EVA_22_Timeline.pdf        [6.7 Mb]
http://www.nasa.gov/sites/default/files/files/us_eva23_timeline2(1).pdf     [4.2 Mb]

Offline mtakala24

Re: EVA Q&A
« Reply #50 on: 06/27/2015 05:09 pm »
Not to mention that there are limited resources onboard the space station. An EVA consumes CO2 scrubbing consumables (well, some can be regenerated), and high pressure oxygen from tanks. Those are very, very expensive to launch.

I once saw a chart showing that for every 1 hour of EVA time, there has been 100 hours of training time with the crew. Plus additional training for skill-based emergency tasks for the contingency "must fix" EVAs.

BTW, I wonder what the FinnishArmy -nick background story is... if any :)

Offline Phillip Clark

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Re: EVA Q&A
« Reply #51 on: 06/27/2015 05:31 pm »
And some of the tasks performed by professional astronauts during EVAs have not been exactly, er, professional - look at some of the Russian EVA stunts.

Which "stunts" are you thinking of?
I've always been crazy but it's kept me from going insane - WJ.

Offline the_other_Doug

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Re: EVA Q&A
« Reply #52 on: 06/27/2015 06:33 pm »
And some of the tasks performed by professional astronauts during EVAs have not been exactly, er, professional - look at some of the Russian EVA stunts.

Which "stunts" are you thinking of?

I'd be thinking of Romanov and Grechko nearly floating out of Salyut 6's airlock and away from the station -- untethered.  Or whatever undisclosed accident left Mir's airlock outer hatch in a state where it would only hold pressure with the help of a handy C-clamp.

Those come to mind quickly.  I'm sure there are others.
-Doug  (With my shield, not yet upon it)

Online Bob Shaw

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Re: EVA Q&A
« Reply #53 on: 08/09/2015 12:58 am »
And some of the tasks performed by professional astronauts during EVAs have not been exactly, er, professional - look at some of the Russian EVA stunts.

Which "stunts" are you thinking of?

Golf.

Offline kevin-rf

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Re: EVA Q&A
« Reply #54 on: 08/10/2015 12:31 pm »
Or whatever undisclosed accident left Mir's airlock outer hatch in a state where it would only hold pressure with the help of a handy C-clamp.
I thought that was them forgetting to seat/insert the O ring in the hatch when they put it back in place. Or maybe I am thinking of a different incident.
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Offline Nicolas PILLET

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Re: EVA Q&A
« Reply #55 on: 08/10/2015 05:13 pm »
I'd be thinking of Romanov and Grechko nearly floating out of Salyut 6's airlock and away from the station -- untethered.

They were both tethered. There are many myths about this spacewalk...
Nicolas PILLET
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Offline Nicolas PILLET

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Re: EVA Q&A
« Reply #56 on: 08/10/2015 05:14 pm »
And some of the tasks performed by professional astronauts during EVAs have not been exactly, er, professional - look at some of the Russian EVA stunts.

Which "stunts" are you thinking of?

Golf.

Of course, US astronaut never played golf during an extra-vehicular activity... :D
Nicolas PILLET
Kosmonavtika : The French site on Russian Space

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