Radiation Medicine

Void · 2015-08-21 17:43:54

Traveling in space is not the same as surviving a nuclear war, but perhaps this article has merit for space travel anyway, perhaps especially if people experience high radiation from a solar flare.

http://medicalxpress.com/news/2015-08-d … hours.html

New drug protects against the deadly effects of nuclear radiation 24 hours after exposure

louis · 2015-08-21 20:00:16

One thing you can be sure of - the various space agencies are not telling all they know about protecting against space radiation through medication.

RobertDyck · 2015-08-21 22:19:00

Well, one of the radiation effects from Hiroshima and Chernobyl was not direct exposure, but rather drinking contaminated water. Radioactive isotopes taken by the body cause much more damage. One particular isotope is iodine. (Don't know the radioactive isotope atomic mass number). A prophylactic is to take iodine pills with regular, non-radioactive iodine. The usual pill is potassium iodide. When the body is saturated, it won't absorb any more. So any radioactive iodine in water or food will just go right through you. Of course too much potassium or iodine can be harmful, so only take it when you know you're about to be exposed.

That's the one I read about. But years ago there was some talk of strontium-90. The body needs strontium for an enzyme that builds bone. It's usually ingested as green vegetables. Every molecule of chlorophyll contains one atom of magnesium, and bones are an alloy of calcium and magnesium. Bones are a composite, a mineral for compressive strength reinforced with a very strong fibre that acts like rebar in concrete. Human bone is carbonated hydroxyapatite, which is hydrated calcium phosphate. The fibre is a protein called collagen. But magnesium is part of the mineral, so you need green vegetables for strong bones. But there are a couple enzymes that aren't part of bone, but are necessary to build bone. These enzymes require strontium and silicon. You normally get these in digestible form from green vegetables. So you need vegetables for a few ingredients, all needed for bones. In the 1970s, the worry was nuclear fall-out would include strontium-90, which would get into your body and cause on-going radiation exposure like iodine.

But those are radioactive isotopes from nuclear weapons. I don't think they're an issue for space. In space you have to deal with direct radiation. Studies by nuclear weapons guys showed insects survive radiation much better than humans. The reason is insects don't have the delicate membranes that we do. The membranes break down. So how do you repair or prevent damage to membranes from radiation? And when membranes are stressed, inflammation can cause further damage resulting in internal hemorrhage and more inflammation. With too much damage to membranes, inflammation and internal hemorrhage will cascade. Sounds like this drug works on the inflammation. Sounds good.

Last edited by RobertDyck (2015-08-22 11:38:47)

GW Johnson · 2015-08-22 08:27:42

Treatment is good, prevention is better. 15-20 cm water is a decent shield for anything the sun has ever been known to throw, and a really good shield for the usual solar flare stuff. That water can be potable, can be wastewater, can even be water content in stored fresh or frozen food.

If you are living in a space vehicle, you have to have some or all of those things on board just to stay alive. Wrap them around a designated shelter space and make them serve as your flare shield, too. If you get caught and exposed outside the shelter, then that's what the drug is for.

GW

RobertDyck · 2015-08-22 12:08:09

That was part of Robert Zubrin's original design for Mars Direct. The air lock was on the upper floor, surrounded by food and water storage. Later designs moved the air lock to the lower floor. It's more convenient to have a stairway lead from ground to an exterior door, and that door lead directly into the airlock. But that means the hab needs an airlock-size room with food and water storage in the walls. A closet would do.

I've also emphasized the lower floor of the hab requires room for landing rocket engines, propellant tanks for the rockets, garage for the rover with a garage door the folds down to act as a ramp, life support, and batteries. And of course the airlock. Remember the hab is powered by solar panels. There's sunlight 24/7 in space during transit, but Mars has night just like Earth. Batteries have to be charged during the day, then large enough to power life support all night. Based on ISS equipment, life support will be as large as 5 refrigerators. The battery would be the same size as a Tesla Powerwall: mounted on a wall 33.9" wide x 51.2" high x 7.1" deep. Designs for MDRS and FMARS do not take any of this into account.

Void · 2015-08-22 13:11:17

This thread is doing much more that I thought it would. Yes, since you need water, and eliminate watery fluids, why not use that as shielding also.

For the design Robert, will the information I have referred to below seem to reduce the overall weight needed? NASA appears to be working on some very interesting things according to what I read.

http://www.projectrho.com/public_html/r … iation.php
http://www.nasa.gov/vision/space/travel … lding.html

Polyethylene is a good shielding material because it has high hydrogen content, and hydrogen atoms are good at absorbing and dispersing radiation. In fact, researchers have been studying the use of polyethylene as a shielding material for some time. One of several novel material developments that the team is testing is reinforced polyethylene. Raj Kaul, a scientist in the Marshall Center's Engineering Directorate, previously has worked with this material on protective armor for helicopters.

The combination of heat and pressure causes the chemical reaction that bonds the layers together to form a brick weighing about half as much as a similar piece of aluminum.

So, maybe it is a magic material for building things on Mars, a desired primary technology for Mars.

Last edited by Void (2015-08-22 13:16:16)

RobertDyck · 2015-08-22 14:14:52

So you're proposing thick polyethylene walls around a radiation shelter? Remember, you want the spacecraft to be light weight, so you don't want heavy shielding around the entire craft. It's primarily hydrogen in water that provides shielding. Water is H2O; each hydrogen atom has an atomic mass of 1.00794, each oxygen 15.9994, total molecular weight 18.01528. Polyethylene has chemical formula (H2C)n where "n" is a large number. Oxygen is replaced by carbon, which has atomic mass 12.0107, total molecular weight for each unit is 14.02658. So polyethylene with the same amount of hydrogen is actually a little lighter. For the same radiation shielding 1 kg water could be replaced with 14.02658/18.01528 = 0.7785935 kg polyethylene. That sounds like a weight saving, until you realize you still need the water anyway. Life support requires water. The logical solution is to shape the water storage tanks as a wall with the thickness GW Johnson specified. You would want ceiling and floors covered by water tanks as well. Food storage would be in cupboards on the inside of this shelter. So consider the shelter to be a food storage closet, aka pantry. You could even use the closet for storage during normal operation, but not so cluttered that you can't get at the food cupboard. And astronauts would have to be able to empty out this closet quickly to use it as a radiation shelter.

Light weight polyethylene door for normal operation? But a sliding door that's actually a water tank, perhaps with flexible bladder inside a hollow door so there's no air in the water storage bladder. That's for zero-G operation. With a hose connecting this door bladder to the rest of the shelter water tank. Say a thin sliding door that slides into a pocket on one side of the shelter, with a thick heavy door that slides into a pocket on the other side. The pocket would be outside the shelter's tank wall to ensure all cupboards inside are accessible.

RobertDyck · 2015-08-22 14:20:43

This thread started as space medicine. The problem is most people here are not medical experts. My first post was on-topic, but can anyone add to that?

Void · 2015-08-22 14:57:48

Some additional topics here:
https://en.wikipedia.org/wiki/Space_medicine

A bit more on radiation:
https://en.wikipedia.org/wiki/Space_med … on_effects

For radiation, though, that's about it.
But An ounce of prevention is worth a pound of cure" it is said, so, I think that actually you could call radiation shielding preventative medicine.

Sleep disorders:
https://en.wikipedia.org/wiki/Space_med … _disorders

I am thinking a temperature controlled chamber of a hydrocarbon liquid (Which can also be a fuel). Actually a tank with an opening the body can be inserted into, with a liquid tight sack that might serve like a sleeping bag. A domed hinged lid over the entrance port. A sensory depravation chamber so to speak.

If that doesn't work then; A soothing quiet music, may help to prevent the mind from ruminating which is usually what keeps me up.

And in spite of what the article says, as a last resort; If that doesn't work, then resort to a movie you have seen 20 times, or something like last of the summer wine, which also can put me to sleep.

RobertDyck · 2015-08-22 18:19:35

Did a quick power calculation. Based on the life support equipment for ISS, detailed in the thread Light weight nuclear reactor, updating Mars Direct, it would require 73 kWh per solar day (24 hours 39 minutes 35.244 seconds) for 4 astronauts. The Tesla Powerwall has two models, one rated for 10 kWh weekly cycle, the other 7 kWh daily cycle. The Mars hab would need the daily cycle, but that means 10 of them. The Tesla site says batteries can be connected for a maximum of 63 kWh for the daily cycle battery. Um, that's 9 Powerwall modules. And power calculation was just life support, not including lighting, computers, communication, lab equipment, heating/cooling. Ok, this is a rough calculation. The Mars version may be different.

Last edited by RobertDyck (2015-08-22 19:04:56)

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Radiation Medicine

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