The syndrome impairing astronauts’ eyesight • Hacker News Board

Re: The syndrome impairing astronauts’ eyesight

#21

Post by imaginenore » Sun, Jul 10, 2016, 3:15 AM UTC

wolf550e wrote: post #9

andrewtbham wrote: post #2

It will not prevent travel to Mars. It's effects can likely be countered. Perhaps by artificial gravity. https://en.wikipedia.org/wiki/Artificial_gravity

Yes, Zubrin has been advocating for this since 1990. https://www.youtube.com/watch?v=3UChuIqIKF4&t=1722 His explanation about the real situation with NASA and why the human spaceflight program has not accomplished anything is extremely disheartening. https://www.youtube.com/watch?v=3UChuIqIKF4&t=417

The real problem is you need to deliver so much material to orbit to create artificial gravity (a rotating space station) it's very expensive.

We could create a simple rotating system with two pods connected by a long cable, but then it's not easy to dock to it, and there are balancing issues.

Re: The syndrome impairing astronauts’ eyesight

#22

Post by lttlrck » Sun, Jul 10, 2016, 3:35 AM UTC

jfoutz wrote: post #11

jerf wrote: post #8

Earlier quoted context omitted.

Artificial gravity is easy. You "just" spin things. The tricky bit is being able to launch enough mass to build something safe and comfortable to spin; there's a limit to how small you can make your spinning habitat before the difference between "centrifugal force" and gravity is too pronounced for our long term comfort. That's part of why making it cheaper to launch per unit mass is so important. If we could put ten…

Two skylabs and a really long rope seems pretty achievable. The full wheel from 60's sci fi looks very cool, but two weights on opposite sides of a string seems so much simpler.

This idea is used in Seveneves

https://en.m.wikipedia.org/wiki/Seveneves

Re: The syndrome impairing astronauts’ eyesight

#23

Post by nxzero » Sun, Jul 10, 2016, 3:50 AM UTC

JoeAltmaier wrote: post #18

ams6110 wrote: post #17

Earlier quoted context omitted.

Now all your space vehicles need to be able to hold together under 1G of force. That means a lot more structure and mass and the cost goes way up.

How about sleeping in a centrifuge? No need for the entire spaceship to spin.

If it was possible to build a gravity sleep chamber, it's very possible that exposing the human body to gravity and zero-gravity on a daily basis would be put more, not less stress on a body than zero-gravity alone.

Re: The syndrome impairing astronauts’ eyesight

#24

Post by nxzero » Sun, Jul 10, 2016, 3:54 AM UTC

jerf wrote: post #14

hoorayimhelping wrote: post #12

Earlier quoted context omitted.

> The tricky bit is being able to launch enough mass to build something safe and comfortable to spin; Is it? I might have a completely busted mental model, but I thought you only need a module-sized mass on one end of a rod the length of things we've already assembled in space (e.g. an ISS truss) and a motor to spin it.

It gets complicated, and the mass budget starts going up fast, if you want other things to be able to dock to it. Two space stations on the opposite side of a long rope (per the other reply) is also not a very compelling story to tell to Congress when you have to admit that astronauts won't be able to travel between those two space stations to speak of, unless, again, you really up the mass budget. We're space-poor.…

What about grabbing mass from the surface of the moon, junk that's floating around, etc.?

Seems like this might be cheaper than getting it off Earth, right?

Re: The syndrome impairing astronauts’ eyesight

#25

Post by ekianjo » Sun, Jul 10, 2016, 4:06 AM UTC

imaginenore wrote: post #21

wolf550e wrote: post #9

Earlier quoted context omitted.

Yes, Zubrin has been advocating for this since 1990. https://www.youtube.com/watch?v=3UChuIqIKF4&t=1722 His explanation about the real situation with NASA and why the human spaceflight program has not accomplished anything is extremely disheartening. https://www.youtube.com/watch?v=3UChuIqIKF4&t=417

The real problem is you need to deliver so much material to orbit to create artificial gravity (a rotating space station) it's very expensive. We could create a simple rotating system with two pods connected by a long cable, but then it's not easy to dock to it, and there are balancing issues.

That should get much cheaper once spacex gets things right.

Re: The syndrome impairing astronauts’ eyesight

#26

Post by wizardhat » Sun, Jul 10, 2016, 4:54 AM UTC

Studies going as far back as the 80s show that people in submarines develop myopia:

http://www.ncbi.nlm.nih.gov/pubmed/7457562

The leading theory is that being in a confined space causes the eye to adapt to viewing things up close rather than at a distance.

Re: The syndrome impairing astronauts’ eyesight

#27

Post by Gracana » Sun, Jul 10, 2016, 5:17 AM UTC

"The only proven methods of measuring intracranial pressure are invasive: the spinal tap or drilling a hole into the skull."

Sounds like we need to test/prove something new. I did some searching for a wireless intracranial pressure sensor and didn't find anything, but I bet you could make one. The sensor could be a pair of capacitor plates on the inside of a sealed cavity in a flexible material, with an antenna attached, such that the capacitance changes as the cavity is squeezed by the pressure around it.

To make a measurement, you'd use an external antenna to hit the sensor antenna with an impulse, which would cause it to ring at a frequency proportional to the pressure it's monitoring.

Very simple, no batteries, could be made very small...

[edit] Oh hey, they mention implanted devices. I guess I should have finished reading the article before posting.

Re: The syndrome impairing astronauts’ eyesight

#28

Post by JoeAltmaier » Sun, Jul 10, 2016, 5:21 AM UTC

nxzero wrote: post #23

JoeAltmaier wrote: post #18

Earlier quoted context omitted.

How about sleeping in a centrifuge? No need for the entire spaceship to spin.

If it was possible to build a gravity sleep chamber, it's very possible that exposing the human body to gravity and zero-gravity on a daily basis would be put more, not less stress on a body than zero-gravity alone.

That's just a random guess. We already lay down for 8 hours and stand up for 16. My random guess is, our fluids would recover with at least some artificial acceleration and why not when sleeping?

Re: The syndrome impairing astronauts’ eyesight

#29

Post by wlievens » Sun, Jul 10, 2016, 6:18 AM UTC

thaumasiotes wrote: post #16

jerf wrote: post #14

Earlier quoted context omitted.

It gets complicated, and the mass budget starts going up fast, if you want other things to be able to dock to it. Two space stations on the opposite side of a long rope (per the other reply) is also not a very compelling story to tell to Congress when you have to admit that astronauts won't be able to travel between those two space stations to speak of, unless, again, you really up the mass budget. We're space-poor.…

> Two space stations on the opposite side of a long rope (per the other reply) is also not a very compelling story to tell to Congress when you have to admit that astronauts won't be able to travel between those two space stations to speak of I don't get the complaint. Assuming travel from one station to the other is impossible, what's supposed to be wrong with having two smaller stations that don't cripple the healt…

Still can't dock. You need to be able to dock in the stationar center module.

Re: The syndrome impairing astronauts’ eyesight

#30

Post by akiselev » Sun, Jul 10, 2016, 7:11 AM UTC

ekianjo wrote: post #25

imaginenore wrote: post #21

Earlier quoted context omitted.

The real problem is you need to deliver so much material to orbit to create artificial gravity (a rotating space station) it's very expensive. We could create a simple rotating system with two pods connected by a long cable, but then it's not easy to dock to it, and there are balancing issues.

That should get much cheaper once spacex gets things right.

Even if SpaceX made the launch costs a hundred times cheaper than the shuttle, it would still cost over $500 million and that would only launch a tiny fraction of the mass needed for a full artifical gravity space station. The estimated cost of the International Space Station so far is over $100 billion not including launch costs so even if another company cut costs there by a factor of ten, thats $10 billion, again a small fraction of what you would need. You can cut out bureaucracy and save money with a private company instead of government agencies but this would be a one off design made for space habitation so there really isn't much room to drastically reduce costs. If you want this thing to also travel around the solar system, you'd need to complicate the design even more because the ISS is solar based and has only orbital correction propulsion which is much cheaper.

It's possible but I don't think it will be economical or practical for a long time.