Scott in Houston wrote:C-dub wrote:
Cooling, isn't it pretty cold in space? Why would heat build up be an issue?
This is one thing people don't realize about space. Yes, it's cold, but there's very little heat transference. You need contact for that. Heat would actually leave an object much quicker in ice water than in space due to contact and heat transference. In space, an object actually retains its heat fairly well relatively speaking.
I'm no engineer/physicist, but I think it would be a matter of
how hot the barrel was, wouldn't it? Machine gun barrels can glow red under extreme use, and they give off part of that heat energy as light. Stars give off part of
their heat energy as light, and that doesn't need contact with a substrate to transfer, does it? The light from stars transfers without there being any atmosphere between the star and earth. In fact, we experience
some of that transfer as heat. So here is my hypothesis:
- A red-hot gun barrel would cool in space at a relatively rapid rate until it had given off enough energy to stop emitting light, at which point the rate of cooling would be greatly reduced as the heat transfers through the bearer's hands and is dealt with by the spacesuit's cooling apparatus. The problem of course is that the insulating layers of spacesuits would impede that heat transference.
Like I said, I'm no rocket scientist, so I'd be interested to know from someone better informed if my guess is correct or not.
Steve133 wrote:Of course, just making sure the cartridge propellant burns is only part of it - most lubricants aren't vacuum-rated, so there's a chance that whatever was used on that gun would boil off or flash-freeze, so the action could lock up..
As far as the effectiveness of lubricants in space, I have an anecdotal but I'm-pretty-sure-it's-true story to offer. As some of you know, my family was part of the Caltech/JPL community. My parents were professors there, and my father in law was a JPL engineer who designed and built guidance packages for a number of spacecraft. One of my good friends who was one of my racetrack pit-partners was also a technician at the Carnegie Institute facility on the Caltech campus, and they were building a gyroscope to be used in one of these guidance packages that was to be sent into space—I think it might have been the Hubble Telescope. The problem was how to lubricate the bearing points of the spinning gyroscope's axis. This is less of a critical issue for a gyroscope that is going to return to earth because of the sheer length of time the lubricant will have to hold up for one that is not going to return. They had a meeting about how to procure a lubricant with the properties of tackiness so that it would adhere well to the parts to be lubricated without migrating to places that did not need it, low volatility so that it would not evaporate away, the ability to absorb tremendous shearing forces, and yet the ability to maintain a thin film at the points of contact between moving parts. Brian got up, left the meeting, went out to the parking lot, and retrieved the can of Bel-Ray motorcycle chain lube from under the seat of his motorcycle. He brought it into the meeting, explained its properties, demonstrated it, and—according to what he told me—the decision was reached to use tiny amounts of motorcycle chain lube at the points of contact. Instead of spending thousands of dollars on research and sophisticated materials, a $3.95 can of chain lube saved the day.
I love those kinds of stories, and I have another one involving my father in law, who saved the government from spending a million dollars on a spacecraft part with a $1.98 piece of wood.
“Hard times create strong men. Strong men create good times. Good times create weak men. And, weak men create hard times.”
― G. Michael Hopf, "Those Who Remain"
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