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The Russians have been using GoPros during the last couple of spacewalks they did (to install the earth observation cameras on the ISS). They have the regular h

by Luc 13y ago

The Russians have been using GoPros during the last couple of spacewalks they did (to install the earth observation cameras on the ISS). They have the regular helmet cams, but also a GoPro around their wrist in a little white box. I'm not sure if they're 'stock' GoPro cameras. The temperature extremes are nothing to sniff at.

IgorPartola 13y ago
But... there is no temperature in space: http://www.universetoday.com/77070/how-cold-is-space/ http://www.universetoday.com/77070/how-cold-is-space/
- lutusp 13y ago
  > But... there is no temperature in space ... That's misleading (and the linked article offers no support for your claim). A vacuum has no temperature, but objects in space certainly do have a temperature and all the normal thermodynamic rules apply. If what you said were true, you could safely approach the sun as long as you didn't come into contact with it. But that's not true. In the neighborhood of the non-planet Pluto, the median temperature is just 33 Kelvins. In the extremes of space, between the stars, the temperature of an object falls to the CMB (http://en.wikipedia.org/wiki/Cosmic_microwave_background http://en.wikipedia.org/wiki/Cosmic_microwave_background), about 2.7 Kelvins. The linked article makes the same points.
  - IgorPartola 13y ago
    Of course. The way I think about it is this: when you go for a space walk, first you are inside the airlock where the temperature is about our usual 293 K or so. Now, you suck all the air out and are in a vacuum. You are insulated, except if you are touching another object, and the heat you are losing through radiating it. So the question is: given a GoPro camera strapped to your wrist, and say, a 30 minute space walk, what temperature will it be once you are back in the airlock and before you pump all the air back in? My hunch is that it will be pretty darn high. After all, it is connected to your wrist, and the inside of your space suite must be at least above 273 K for you to be able to do anything.
    - lutusp 13y ago
      > So the question is: given a GoPro camera strapped to your wrist, and say, a 30 minute space walk, what temperature will it be once you are back in the airlock and before you pump all the air back in? My hunch is that it will be pretty darn high. Think about this. One of a spacesuit's key features is that it uses insulation to protect the astronaut from the temperature of space (meaning those objects, however distant, that exchange heat energy with the spacesuit via radiation). This means the spacesuit's exterior will quickly rise or fall to the temperature of its environment. That, in turn, means the GoPro camera will also rise or fall to the temperature extremes of its environment. So, if the astronaut is located in a shadowed environment -- let's say on the moon -- the spacesuit exterior and the GoPro camera will fall close to the temperature of space, or the temperature of the shadowed areas of the moon: http://www.nature.com/news/2009/091217/full/news.2009.1149.html http://www.nature.com/news/2009/091217/full/news.2009.1149.h... Quote: "Previous findings had identified the Moon as the coldest place in the Solar System, but the latest results push the temperature even lower, all the way to 26 kelvin ..." The above refers to the shadowed areas of the moon. Pretty damn cold. :) But -- if the astronaut walks around in the sunlit parts of the moon, the temperature will be very high. My point is the astronaut's temperature inside the suit isn't the issue, and the more efficient the suit, the less its external temperature reflects that of its occupant. So the GoPro camera would have to tolerate a very wide temperature range. > After all, it is connected to your wrist, and the inside of your space suite must be at least above 273 K for you to be able to do anything. A spacesuit that externally radiated any significant energy at room temperature would be a very poor design indeed. And the GoPro camera isn't attached to the astronaut's wrist, it's attached to the spacesuit wrist area.
      - IgorPartola 13y ago
        I understand what you are saying about things like the Moon, Pluto, etc. If a bury a thermometer on the moon, and dig it up 5 minutes later, it will be very cold. But we are talking about a space walk here. Let's phrase the question this way: if I have a 1 kg mass of plastic and metal in some proportion and I throw it out of the airlock with the initial temperature of 293 K, what will its temperature be 30 minutes later if it was (a) in the shadow and (b) in the sunlight? This is a different case than being in contact with a hot or cold satellite or planet. It's a rate problem. If we assume a near-perfect vacuum, the only heat going in and out is via radiation. So the question is, how fast does a hunk of metal/plastic radiate heat at 293 K. Now, the radiation heat transfer out of a black body will be: q = σ T^4 A, where q is the Watts of heat transferred, σ is the Boltzman constant, T is the temperature in Kelvin, and A is the surface area. Roughly: 5.6703e-8 x 293 x 0.1 for a GoPro camera. That's 1.66e-6 Watts, or 1.66 microwatts. That's a pretty damn low transfer rate: we are talking about roughly 3 mJ of energy lost over 30 minutes. Now, the delta T here is equal to Q/(mC), where Q is our 0.003 Joules, m is the mass, 0.135 kilograms, and C is the specific heat. The specific heat is tricky but let's assume this thing is made out of copper: 390 J/(K kg). That gives us a delta T of, drum roll please, 5.7e-5 degrees. So assuming we are in the shade and are not touching cold objects, the GoPro will come back at the exact temperature it left after a 30 minute space walk. We can of course figure out what it will be in the sun, where I expect it'll heat up quite a bit, which is probably the more dangerous thing for a piece of equipment. The equations are nearly the same.

by Luc 13y ago

IgorPartola 13y ago

But... there is no temperature in space: http://www.universetoday.com/77070/how-cold-is-space/ http://www.universetoday.com/77070/how-cold-is-space/

lutusp 13y ago
> But... there is no temperature in space ... That's misleading (and the linked article offers no support for your claim). A vacuum has no temperature, but objects in space certainly do have a temperature and all the normal thermodynamic rules apply. If what you said were true, you could safely approach the sun as long as you didn't come into contact with it. But that's not true. In the neighborhood of the non-planet Pluto, the median temperature is just 33 Kelvins. In the extremes of space, between the stars, the temperature of an object falls to the CMB (http://en.wikipedia.org/wiki/Cosmic_microwave_background http://en.wikipedia.org/wiki/Cosmic_microwave_background), about 2.7 Kelvins. The linked article makes the same points.
- IgorPartola 13y ago
  Of course. The way I think about it is this: when you go for a space walk, first you are inside the airlock where the temperature is about our usual 293 K or so. Now, you suck all the air out and are in a vacuum. You are insulated, except if you are touching another object, and the heat you are losing through radiating it. So the question is: given a GoPro camera strapped to your wrist, and say, a 30 minute space walk, what temperature will it be once you are back in the airlock and before you pump all the air back in? My hunch is that it will be pretty darn high. After all, it is connected to your wrist, and the inside of your space suite must be at least above 273 K for you to be able to do anything.
  - lutusp 13y ago
    > So the question is: given a GoPro camera strapped to your wrist, and say, a 30 minute space walk, what temperature will it be once you are back in the airlock and before you pump all the air back in? My hunch is that it will be pretty darn high. Think about this. One of a spacesuit's key features is that it uses insulation to protect the astronaut from the temperature of space (meaning those objects, however distant, that exchange heat energy with the spacesuit via radiation). This means the spacesuit's exterior will quickly rise or fall to the temperature of its environment. That, in turn, means the GoPro camera will also rise or fall to the temperature extremes of its environment. So, if the astronaut is located in a shadowed environment -- let's say on the moon -- the spacesuit exterior and the GoPro camera will fall close to the temperature of space, or the temperature of the shadowed areas of the moon: http://www.nature.com/news/2009/091217/full/news.2009.1149.html http://www.nature.com/news/2009/091217/full/news.2009.1149.h... Quote: "Previous findings had identified the Moon as the coldest place in the Solar System, but the latest results push the temperature even lower, all the way to 26 kelvin ..." The above refers to the shadowed areas of the moon. Pretty damn cold. :) But -- if the astronaut walks around in the sunlit parts of the moon, the temperature will be very high. My point is the astronaut's temperature inside the suit isn't the issue, and the more efficient the suit, the less its external temperature reflects that of its occupant. So the GoPro camera would have to tolerate a very wide temperature range. > After all, it is connected to your wrist, and the inside of your space suite must be at least above 273 K for you to be able to do anything. A spacesuit that externally radiated any significant energy at room temperature would be a very poor design indeed. And the GoPro camera isn't attached to the astronaut's wrist, it's attached to the spacesuit wrist area.
    - IgorPartola 13y ago
      I understand what you are saying about things like the Moon, Pluto, etc. If a bury a thermometer on the moon, and dig it up 5 minutes later, it will be very cold. But we are talking about a space walk here. Let's phrase the question this way: if I have a 1 kg mass of plastic and metal in some proportion and I throw it out of the airlock with the initial temperature of 293 K, what will its temperature be 30 minutes later if it was (a) in the shadow and (b) in the sunlight? This is a different case than being in contact with a hot or cold satellite or planet. It's a rate problem. If we assume a near-perfect vacuum, the only heat going in and out is via radiation. So the question is, how fast does a hunk of metal/plastic radiate heat at 293 K. Now, the radiation heat transfer out of a black body will be: q = σ T^4 A, where q is the Watts of heat transferred, σ is the Boltzman constant, T is the temperature in Kelvin, and A is the surface area. Roughly: 5.6703e-8 x 293 x 0.1 for a GoPro camera. That's 1.66e-6 Watts, or 1.66 microwatts. That's a pretty damn low transfer rate: we are talking about roughly 3 mJ of energy lost over 30 minutes. Now, the delta T here is equal to Q/(mC), where Q is our 0.003 Joules, m is the mass, 0.135 kilograms, and C is the specific heat. The specific heat is tricky but let's assume this thing is made out of copper: 390 J/(K kg). That gives us a delta T of, drum roll please, 5.7e-5 degrees. So assuming we are in the shade and are not touching cold objects, the GoPro will come back at the exact temperature it left after a 30 minute space walk. We can of course figure out what it will be in the sun, where I expect it'll heat up quite a bit, which is probably the more dangerous thing for a piece of equipment. The equations are nearly the same.