How to make a realistic Artificial Gravity for spacecraft?

Hi guys,

I proceed working on a hard sci-fi video game concept. The game takes place in XXII century aboard the "Daedalus" Venus Space Station. I try to achieve the hard sci-fi realism in various details about the setting to make space studies more popular among the audience.

My today’s set of questions is about gravity: zero gravity and artificial gravity for the terms of spacecraft.

PART I: ZERO GRAVITY KILLS

So, according the NASA Office of Inspector General report from October 2015 (http://ift.tt/1qVkhst), one of the major obstacles for the long-term stay in space is zero gravity (or weightlessness) which cause following serious deleterious effects on human health:

1. Loss of Bone Mass (or Spaceflight Osteopenia) – modern astronauts lose 1-2% bone mass per month spent in space. That inflicts critical negative effect on human health. Excessive bone loss and the associated increase in serum calcium ion levels will interfere with execution of mission tasks and result in irreversible skeletal damage. Current countermeasures (increasing dietary calcium, vitamin D, clay eating) can only slow down the process. Though, the only achievable future solution is artificial gravity.

2. Loss of Muscle Mass – another critical negative effect involves the loss of muscle mass. Without the effects of gravity, skeletal muscle is no longer required to maintain posture and the muscle groups used in moving around in a weightless environment differ from those required in terrestrial locomotion. The muscles start to weaken and eventually get smaller. Consequently, some muscles atrophy rapidly, and without regular exercise astronauts can lose up to 20% of their muscle mass in just 5 to 11 days. The types of muscle fiber prominent in muscles also change. Slow twitch endurance fibers used to maintain posture are replaced by fast twitch rapidly contracting fibers that are insufficient for any heavy toil. Despite nowadays each astronaut spends at least two hours per day exercising on the equipment, various treadmills (like COLBERT), the aREDs (advanced Resistive Exercise Device), stationary bicycles can only slow down the process. The only achievable future solution is artificial gravity.

3. Fluid Redistribution – in space the autonomic reactions of the body to maintain blood pressure are not required and fluid is distributed more widely around the whole body. This results in a decrease in plasma volume of around 22%. Because it has less blood to pump, the heart will atrophy. A weakened heart results in low blood pressure and can produce a problem with "orthostatic tolerance," or the body’s ability to send enough oxygen to the brain without the astronaut's fainting or becoming dizzy. Upon return to earth, the blood begins to pool in the lower extremities again, resulting in orthostatic hypotension. Because weightlessness increases the amount of fluid in the upper part of the body, astronauts experience increased intracranial pressure. Beyond that, due to increases pressure on the backs of the eyeballs, it affects their shape and slightly crushing the optic nerve. No cure exists; the only achievable future solution is artificial gravity.

4. Motion Sickness (or Space Adaptation Syndrome) – not very pleasant but for up to 52h human brain adapts. Caused by the conflict between what the body expects and what the body actually perceives. Can be easily surprised by transdermal dimenhydrinate anti-nausea patches (which are usually used nowadays whenever space suits are worn because vomiting into a space suit could be fatal).

Am I correct?

PART II. ARTIFICIAL GRAVITY DRAFT

Okay, based on the Nautilus-X drafts (http://ift.tt/1MHFUAq) let’s imagine such centrifuge (c-Gravity Ring, as it is called on Daedalus). Artificial gravity, here is a result of the use of particularly centripetal force. The only (but decent) issue to make such structure nowadays is the size (hence, the cost) of the spacecraft required to produce centripetal acceleration.

But we’re speaking about realistic 2100+ with all resources of NASA, ESA, Roskosmos, CNSA, ISRO, JAXA, CSA, UKSA, CSAE, CSIRO and ISA combined...

1. Dimensions of the Universal Node: I’ve made the first schemes of the universal modules such c-Gravity Ring might be constructed from (marked them as “colored Nodes”): Blue Node (with 3 gateways), Red Node (with 2 gateways and one “window”), Black Node (with 2 gateways): As they are almost cylindrical, each module is: Length: 16m; Height: 10m; Width 3m. With Pressurized Height: 12m; Pressurized Radius: 2m. Hence, its Pressurized Volume: V = πr²h = 3.14412 = 150m3. // N.B. The ISS’ PV is 916m3.

2. c-Gravity Ring Radius: Than we need to attach those universal modules into regular 16-gon (I tried various modules size combination and came to that 16-gon for the colored modules above as the most realistic) “ring” and calculate the radius of the proper c-Gravity Ring, where S is the length of any side, n is the number of sides: c-Gravity Ring Radius = S / ( 2sin(180/n) ), = 16 / (2sin11.25) = 16 / (2*0.195) = 16 / 0.39 = 41m. // N.B. Nautilus-X’s centrifuge has R of 14m.

3. c-Gravity Ring Rotation Speed: As we want to make Centrifugal Force (F = mw²Radius) be equal to the Gravity Force on Earth surface (F = mg), that leads to w²Radius = g, where g = 9,8m/s2 and Radius we already calculated above (Radius = 41m). Thus: c-Gravity Ring Rotation Speed = sqrt (g/Radius) = sqrt (9.8/41) = sqrt(0.239) = 0.489 rad/s = 4.67 rev/min. // N.B. Nautilus-X’s centrifuge has RS of 10 rev/min.

Does my rough calculations looks realistic?

PART III. GYROSCOPE AXIS STABILIZATION IN SPACE

Well, the rotation of Nautilus-X’s centrifuge as well as the rotation of the c-Gravity Ring turns the whole spacecraft into a huge gyroscope in space. That is definitely good because it helps to fix the VSS on the exact position above the Venus surface. Rotation of the ring is provided by the drives situated on the c-G Ring surface opposite each other.

http://ift.tt/1qVkjjR ; http://afterreset.com/Daedalus/daedalus_colornodes.png

Though, having studied gyroscope in space behavior I didn’t get it: how could we stabilized the axis of the spacecraft so that it doesn’t rotate with the c-G Ring (Nautilus-X’s centrifuge)? Should additionally drives be placed on the axis to compensate the Ring’s rotation? If so, wouldn’t it break the gyroscope effect of the whole construct?

Thank you, for all cool thing you’ve made a reality and for the guidance in advance :)

Submitted April 19, 2016 at 12:56AM by MrNixonOnReddit http://ift.tt/1TghJhN