Why can't you light a candle in a spaceship?

1. 69

   Nose-in-the-Newsposted 10 years ago

   Why can't you light a candle in a spaceship?

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2. 74

   Wakerraposted 10 years ago

   I would imagine it would have to do with the oxygen that is available.  Fire needs oxygen to burn, Space is devoid of Oxygen, so the amount of Oxygen on a spaceship is limited, and probably highly controlled depending on how many astronauts are on board.  I'm sure they have a filtration system set up somehow, but again, its probably finely tuned to basic need/use, so any fires could disrupt that

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   1. 69

      Nose-in-the-Newsposted 10 years agoin reply to this

      Space is a vacuum, but spaceships have a controlled atmosphere that would be similar to that of Earth. Therefore, it would contain sufficient oxygen, so why wouldn't a candle light?

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   2. 74

      Wakerraposted 10 years agoin reply to this

      It would light, just burn out the oxygen quicker.  I believe there are filters on ships to help with the CO2 problem, but I'm imagining its all very calculated and specific for money costs etc.  Just a speculation

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3. 85

   Laura Schneiderposted 10 years ago

   As far as I know there is no scientific reason why one couldn't light a candle in a spaceship because, as you and Wakerra commented above, a manned spaceship is designed to have a similar atmosphere to that on earth to support the humans onboard. I think, however, that the close quarters of a spaceship--meaning you are within close proximity to many things like oxygen tanks that can explode--is the main reason why you can't light a candle in a spaceship. A close secondary reason is as Wakerra said: the amount of oxygen on a spaceship is limited, and candles would use that supply up quickly and needlessly as well as mess up the air filtration systems.
   
   Yet another reason is that, without gravity and with the constant atmosphere on a spaceship, I think it would be hard/impossible to extinguish a candle, let alone safely. You would either have to pinch it off with your fingers or cut off the wick and wait until that wick has burned itself out.
   
   If fire is to be used inside a spacecraft, such as to perform a scientific experiment, I imagine it would need to be done within a closed box, much like an incubator.
   
   Also, because the Apollo 1 mission burned up and killed all of the crew on the launchpad in early 1967, I think NASA is particularly sensitive to this subject. Conditions inside the cockpit are totally different now, mimicking the earth's atmosphere and not pure oxygen as they were in Apollo 1, yet that specter haunts us and the space program today: three heroic astronauts died that day. The American people have essentially a zero-tolerance for death and failures in the space program; an unrealistic expectation, in my opinion, that is holding us back greatly.
   
   Note that welding and soldering torches can be used outside the spacecraft because the source of gas is provided and can be turned off with a valve to extinguish the flame. That is how the space shuttles were repaired in space and how the international space station is being built: with real welds, not SuperGlue. ;-)

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   1. 69

      Nose-in-the-Newsposted 10 years agoin reply to this

      Fantastic answer! Thank you for your efforts!

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   2. 85

      Laura Schneiderposted 10 years agoin reply to this

      You're welcome! I had fun thinking through what would and wouldn't be possible or practical, and going into space has been my dream for as long as I can remember so I read a lot about it. (Thanks for voting this Best Answer!)

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