ISS emergency spacewalk to repair ammonia leak [live video] | Hacker News Reader

ISS emergency spacewalk to repair ammonia leak [live video]

nasa.gov

57 points6ren13 comments

First the trailer for Gravity comes out and then this happens. It's almost as if real life decided space needed a marketing stunt.

http://www.youtube.com/watch?v=ufsrgE0BYf0

And now fixed! Only 48 hours after the leak was detected.

Interesting that they hook-up the "broken" module back into the system for diagnostics.

Probably too dangerous to bring back inside with several pounds of ammonia in it. Might as well just let it RIP outside.

The protocols for space walks are also very similar to deep sea divers. The suits have an internal air pressure lower than the space station (for many good reasons). In order to avoid getting symptoms similar to the bends, they have to spend several hours pre-breathing pure oxygen etc. This means they can't just put on a suit and go outside in an emergency - it takes planning and time.

Could you explain why this is the case?

My guess would be that full pressurization makes the suit too rigid.

The ISS is pressurized to match Earth at sea level (it's designed for long-term habitation), and the pressurized modules are built to withstand that pressure.

Making a spacesuit that could handle the same pressure would require it to be much heavier and more rigid. Cutting the pressure makes it much easier to work in.

This section explains pressures: http://en.wikipedia.org/wiki/Space_suit#Operating_pressure

This 4 minute 1987 NASA video explains suit history: https://www.youtube.com/watch?v=X4WK6IUQ7QU

This page explains the protocol and over two hours of pre-breathe: http://spaceflight.nasa.gov/station/eva/outside.html

This section (4th paragraph) explains what happens when a space suit is pressurized: http://en.wikipedia.org/wiki/Gemini_9A#Objectives

Quote: After pumping up his pressure suit to three and one half pounds of pressure per square inch, "the suit took on a life of its own and became so stiff that it didn't want to bend at all." He struggled to move inside his stiff suit.

Very informative, thanks!

Since it's not so easy to take it down to the shop to check it out, that's probably the only way they can find out what went wrong with it.

The ustream link seems to be the one that works on Android. The HTML 5 one just tells me that I should be using an iOS device.

Does anyone know what technology is being used in the suit cameras and why it is so different from the ISS cameras? The former seem to have far greater interference.

I don't know the details and also I don't know to which ISS cameras you compare, but those suit cameras have to be robust, flexible, likely low power consuming and bring a good reception. The interference with this analog technology isn't that bad. A human viewer can filter those troubles in real time. Compared to a digital video stream, we would have had green blocks, frozen images, delays etc. at least when using the same bandwidth. There could be improvements for sure, but maybe it isn't worth the effort.

Thank you for the post. Been transfixed for more than an hour.

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