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There was an ongoing discussion on how fisher pen was invented independently for safer writing method.

I was just wondering weather we can use chalk and blackboard in space?

Also if there are challenges in making regular use of it, what are the solutions to the challenges.

Talk is Cheap Show me Code
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There's no scientific reason against using a chalkboard, zero gravity isn't an impediment as making a mark is dependent on pressure between the chalk and the board. The reasons for not using chalk are all practical:

  • Chalk boards are bulky and heavy
  • Chalk marks are not fine, you have to write large which is impractical in cramped conditions
  • Getting enough pressure on the board may be tricky in zero gravity
  • Chalk creates dust, this is a problem for a number of reasons
    • Chalk dust will get sucked into the fans that cool computers and other machinery, possibly causing component failure in the future
    • Chalk dust will clog air filters, or at least reduce their useful life
    • Most of all, chalk creates dust which is a throat and eye irritant
GdD
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    The dust issue is also why most places I know have already eliminated or are in the process of phasing out chalk boards in favor of white boards and dry erase markers even down here on Earth. – Darrel Hoffman Sep 07 '21 at 15:40
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    Also: erasing chalk requires considerable amount of water. – pabouk - Ukraine stay strong Sep 08 '21 at 08:30
  • I'd hesitate to put that down @pabouk, I'm sure space agencies could engineer a way around that if they wanted to. – GdD Sep 08 '21 at 10:06
  • @pabouk Erasing chalk marks requires no water. You need only a tool that can get into the rough crevices of the chalkboard surface and keep hold of the chalk marks it lifts. A cloth with a low-tack adhesive would work. – Suncat2000 Sep 08 '21 at 16:20
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    The reason dust is a problem in space but not in a classroom is because in a classroom dust falls down into the tray under the chalkboard and stays there. In space there is no down. – candied_orange Sep 08 '21 at 21:03
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    That's true to a point @candied_orange, on earth fine dust stays in the air and irritates eyes and noses, that's why blackboards have been phased out. – GdD Sep 09 '21 at 07:40
  • @GdD I'm not going to presume to know the primary reason they were phased out but in my experience the only time flying dust was a problem was when you beat the erasers to clean them. I always assumed people simply preferred the higher contrast. – candied_orange Sep 09 '21 at 14:14
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    @candied_orange There's also the noise issue. "Nails on a chalkboard" is synonymous with painful sound for a reason. – Darrel Hoffman Sep 09 '21 at 20:10
  • That sets my teeth on edge just thinking about it @DarrelHoffman! – GdD Sep 10 '21 at 06:52
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@GdD's answer is complete, but I'll elaborate on the chalk dust.

They pretty much can't even have bread or cake on the ISS due to the crumb production; a manual chalk-dust generator would be a nightmare in comparison.

And the work involved in going outside to banging the erasers together to clean them is more trouble than it's worth. I predict that if there were chalk boards and erasers on the ISS they'd just put the dirty erasers in the trash like they do towels and used clothes, and get new ones each time.

lower volume first:

crust-encapsulated, bite-sized "space breadlet" one can pop in one's mouth to avoid making crumbs, from https://space.stackexchange.com/a/42071

space breadlet

uhoh
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    Banging the erasers wouldn't be that big a problem--build something that can do it outside. The rest of it, though--nobody's flying chalk! – Loren Pechtel Sep 07 '21 at 03:18
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    @Loren Good point! Gee, the automatic orbital eraser-banger and associated feedthrough port sounds like a great phase II SBIR contract – uhoh Sep 07 '21 at 03:50
  • Wouldn’t the air filters take care of the chalk dust? – Michael Sep 07 '21 at 06:51
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    @Michael - of course they would. And then, they'd need cleaning out or replacing far more often. – Tim Sep 07 '21 at 07:31
  • @LorenPechtel, then you just build up a cloud of chalk dust that stays in orbit around your craft. No wind to blow it away, no gravity for it fall to the ground like it does on Earth. It's just going to stay there. That's going to create other problems. – Seth R Sep 07 '21 at 14:45
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    @SethR But the drag-to-mass ratio of chalk dust will be very different than that of the ISS, so it would not just 'hang around' – Mr47 Sep 07 '21 at 14:56
  • @Mr47 Not just drag. TESS is in a cislunar orbit, beyond the residual atmosphere the ISS experiences. Solar wind is the fluid medium, but the dominant force on dust is light pressure. We occasionally see dusty debris from micrometeorite impacts in the field of view. It accelerates away due to light pressure. – John Doty Sep 07 '21 at 15:36
  • While an external chalk dust cloud would likely eventually drift away, it could likely cover important systems on the outside of the spacecraft. – BillThePlatypus Sep 07 '21 at 15:49
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    There's the risk of potato chips. – Pete Becker Sep 07 '21 at 16:15
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    @SethR It's going to have some initial velocity, it will depart. So long as you have a shield (it can be very lightweight material) that keeps dust from heading towards any other part of the ISS it will be fine. The danger is chalk inside. – Loren Pechtel Sep 08 '21 at 01:31
  • @PcMan The pneumatic effect is significant but inertia is also a significant factor in dislodging the dust from the erasers. It would be productive, but still messy. As for "breadlets", maybe the next module launched can include an Auntie Anne's soft pretzel stand. – Suncat2000 Sep 08 '21 at 16:26
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    Bang erasers to clean?.. I always washed them with water and cleaned the blackboard with a wet eraser. This takes time to dry, but doesn't leave too much residual graphics. This isn't too easy in space either though, but definitely doesn't produce as much dust as banging. – Ruslan Sep 08 '21 at 20:52
  • @PcMan where does this theory of pneumatic eraser cleaning come from? If you can expand on it and add some combination of physics, math and source citations it can be posted as an answer. – uhoh Sep 08 '21 at 23:39
  • @Ruslan I'd never thought of that nor seen it done, but it certainly sounds like a great idea/better solution! – uhoh Sep 08 '21 at 23:40
  • @PcMan I was hoping some bored physics graduate students had done an experiment with some erasers and a vacuum chamber and published it somewhere :-) – uhoh Sep 09 '21 at 00:40
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What hasn't been mentioned yet is the problem Fisher solved with the "Space Pen": Normal ball point pens need gravity to pull the ink down towards the ball at the bottom; they would not write for extended periods of time against or even without gravity. According to the Wikipedia page ball point pens were popularized in the U.S. only in the 1950s by Marcel Bich through the now ubiquitous Bic brand. They were as much bleeding (or hopefully not bleeding!) edge technology as space travel itself. The "Space Pen" had a pump mechanism which could pressurize the ink reservoir, thus forcing the ink towards the ball.

Of course, chalk is not subject to the complications of fluid dynamics under zero gravity ; there is no flow of substance but just abrasion, which works under about all conditions which does not melt, evaporate or otherwise compromise the two surfaces involved.

Peter - Reinstate Monica
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    I seem to recall there was a test of this, and regular old cheap ballpoints worked perfectly fine in zero G, as they operate mainly by capillary action rather than gravity. You can test this on Earth by using a regular pen while writing on paper against the ceiling (or some other surface above you). The actual problem solved by the space pen is one of ink leakage under pressure/temperature differentials and outgassing of the ink. (Also most astronauts were perfectly happy using pencils before that - often grease pencils designed to not create dust or shavings.) – Darrel Hoffman Sep 09 '21 at 14:21
  • @DarrelHoffman I believe you're correct on that regular ballpoints work fine in zero G, but trying to write on the ceiling in one G will quickly show that capillary action in ballpoints is insufficient to overpower Earth's surface gravity. – 8bittree Sep 13 '21 at 20:02
  • @8bittree A better test might be to use the wall? With the pen perfectly horizontal, the effect of gravity on the ink should be basically nil. I do remember seeing someone do the ceiling test on YouTube somewhere, and it seemed to mostly work, but it might depend on the pen. – Darrel Hoffman Sep 13 '21 at 20:18