The First Humans on Mars

louis · 2018-04-14 04:50:38

1G can be simulated during the day by weighted suits, in terms of muscle power. I was thinking more of other effects e.g. on the immune system, although the causality is as yet poorly understood.

Terraformer wrote:

I think a 1G centrifuge sleeping pod might provide an interim solution to the 0.38 G issue on Mars.
Louis, we use bed rest to simulate microgravity. Sleeping in a centrifuge isn't going to help much.

Oldfart1939 · 2018-04-14 09:07:43

I suspect that the effect observed, regarding the immune system, may be related to loss of bone marrow where the stem cells for blood cell replacement originate. In a way, this may be an important clue about the origin of "gravity receptors," which as now, we haven't a clue as to how all these effects observed are triggered. Somehow, we need to pay more attention to provision of some level of artificial gravity by centripetal acceleration--spin induced--for things to turn out well for the astronauts involved.

One of these early missions MUST include some type of "tether" system and attempt to use spin generated gravity.

SpaceNut · 2018-04-14 09:13:29

I am also wondering about the good bacteria that makes the human body work? Does it also change with the lack of gravity?

GW Johnson · 2018-04-14 09:57:28

Look, there will be some benefit to low gravity on Mars (0.38 gee) or the moon (0.16 gee). We just don't know what it will be, because policy-wise, we were just too stupid to have investigated it with a spinning space station all these decades.

What we know is restricted to 3 broad things: (1) we evolved and do as well as is possible at 1 gee, (2) we suffer serious problems exposed to 0 gee, with irreversibilities and accumulating damage the longer the exposure, and (3) bed rest about 3 or 4 degrees head-down can simulate some but not all of the effects of 0 gee. The rest is details, learned over decades of effort at only 1 and 0 gee.

A typical trip to and from Mars will be a few to several months in transit (most folks presume 0 gee for this), months to years on Mars at 0.38 gee, and a few to several months in transit coming home (again most folks presume 0 gee for this). Our experiences sending crews on extended space station missions ever since Skylab says a 0-gee weakened astronaut can survive a 4 gee reentry after missions ranging up to just over a year.

If (and only if) 0.38 gee at Mars is therapeutic enough to maintain a level of fitness comparable to 1 gee fitness, then a low-gee return reentry at Earth is feasible, for 0-gee transits home. But, free return at interplanetary trajectory speeds (about 17 km/s) is a very high-gee entry: nearer 12-15 gee, or perhaps even higher. Only full 1 gee fitness survives that!

What that is really telling you is that you must provide near 1 gee spin gravity on the trip home, even if the free-return is only an emergency bailout mode. Otherwise, you will kill your crew during the last 3 minutes to touchdown. And just how stupid would that be?

Now those are the facts, and no amount of wishful thinking is going to change them.

Not even NASA has faced up to that. Not yet, anyway.

Spacex is banking on 0.38 gee being fully therapeutic (when no one can yet know that), coupled with as short a ride home as they can achieve. But they are doing a free return. I have yet to see what their predicted reentry gees are at Earth from that trajectory. For a capsule, 12-15 gees scales fairly well from Apollo's 11 gee ride at 11 km/s entry speed.

GW

Last edited by GW Johnson (2018-04-14 10:03:59)

louis · 2018-04-14 12:53:06

Your suggestion about bone marrow is interesting.

But I can't imagine Space X are going to rush blindly into this. My expectation is that there will be a Mars simulation mission to the Moon. We will then see how well people can operate on such a mission. The alternative of building a spinning rocket carries its own risks, not least malfunction which could lead to a mission abort.

Oldfart1939 wrote:

I suspect that the effect observed, regarding the immune system, may be related to loss of bone marrow where the stem cells for blood cell replacement originate. In a way, this may be an important clue about the origin of "gravity receptors," which as now, we haven't a clue as to how all these effects observed are triggered. Somehow, we need to pay more attention to provision of some level of artificial gravity by centripetal acceleration--spin induced--for things to turn out well for the astronauts involved.
One of these early missions MUST include some type of "tether" system and attempt to use spin generated gravity.

Oldfart1939 · 2018-04-14 14:12:48

Louis-

The guys at SpaceX are almost all engineers, and are looking virtuall exclusively at the engineering problems involved in simply just getting a rocket to Mars. They are great, but aren't globally omniscient; they don't see all, and neither does NASA. I was professionally looking at the bone loss problem independently of any requests for proposals as early as 2007; only in the past year or so has NASA even started looking at this issue with issuance of requests for proposals. The bone loss under prolonged microgravity conditions was my initial clue about the potential relationship with bone marrow, which produces erythroblasts as stem cells for replacement of erythrocytes (red blood cells). There is also the source of osteoblasts (bone stem cells) in the marrow. This has caused me to focus on the biology and biochemistry of bone marrow in order to begin asking the right questions. My question is whether bone marrow houses the secretive "gravity receptors." Or something that acts as such.

Last edited by Oldfart1939 (2018-04-14 20:03:17)

RobertDyck · 2018-04-14 16:34:23

I also believe 38% gravity is sufficient to avoid clinical problems of 0G. I have suggested that some cellular chemical reactions require intra-cellular convection, which requires gravity. What is the right term, "endo-something"? Oldfart suggested some sort of "gravity receptors"; could be. But this means lunar gravity (16.54%) might be sufficient. The only difference being low load on muscle and bone causing muscle atrophy and bone loss, but only to the extent of adaptation to the new gravity. Exercise could alleviate that.

But my mission plan is a modification of Robert Zubrin's Mars Direct. I like his idea of artificial gravity in transit to Mars. My plan uses it for return as well. That means 6 months of fully immersed in 1g before landing on Earth. Astronauts should be reconditioned by then. While on Mars, between wearing the weight of a spacesuit and hikes out on the surface of Mars to explore, astronauts should receive sufficient exercise without requiring weighted suits.

Last edited by RobertDyck (2018-04-14 18:06:23)

louis · 2018-04-14 17:28:04

Another fact is isolation. It is known that socially isolated persons have weaker immune systems than people who are fully integrated into society. The assumption appears to be that is because of mind-body effects, negative emotional states affecting hormonal systems. But could it be that isolation simply restricts exposure to pathogens, so the immune response gets sluggish, just as our muscles get sluggish in 1G because they don't have work to do.

This paper suggests that people at Antarctic bases - in 1G environments obviously - suffer weakened immune systems and that this is partly to do with physical isolation plus the emotional stress of their social isolation. The same could certainly apply to ISS crew, but even more so as they are more isolated.

https://www.karger.com/Article/FullText/339512

Oldfart1939 wrote:

Louis-
The guys at SpaceX are almost all engineers, and are looking virtuall exclusively at the engineering problems involved in simply just getting a rocket to Mars. They are great, but aren't globally omniscient; they don't see all, and neither does NASA. I was professionally looking at the bone loss problem independently of any requests for proposals as early as 2007; only in the past year or so has NASA even started looking at this issue with issuance of requests for proposals. The bone loss under prolonged microgravity conditions was my initial clue about the potential relationship with bone marrow, which produces erythroblasts as stem cells for replacement of erythrocytes (red blood cells). There is also the source of osteoclasts (bone stem cells) in the marrow. This has caused me to focus on the biology and biochemistry of bone marrow in order to begin asking the right questions. My question is whether bone marrow houses the secretive "gravity receptors." Or something that acts as such.

SpaceNut · 2018-04-14 19:17:36

There is something else in the winter, that is seasonal depression and at appears to be a factor for those that come from a warm sunny climate to the station. The experiment can be altered since we have lights now for that seasonal depression due to the extended winter.

People use light therapy to treat seasonal affective disorder (SAD), which is depression related to shorter days and reduced sunlight exposure during the fall and winter months. Most people with SAD feel better after they use light therapy.

https://en.wikipedia.org/wiki/Seasonal_ … e_disorder

6 Types of Light Therapy for Seasonal Depression

louis · 2018-04-14 20:04:27

Multiple dawn/dusk in Earth orbital space must have some negative effect as well, being so unnatural...that wouldn't be a problem on the journey to Mars - we could create artificial night and day on Earth time.

SpaceNut wrote:

There is something else in the winter, that is seasonal depression and at appears to be a factor for those that come from a warm sunny climate to the station. The experiment can be altered since we have lights now for that seasonal depression due to the extended winter.
People use light therapy to treat seasonal affective disorder (SAD), which is depression related to shorter days and reduced sunlight exposure during the fall and winter months. Most people with SAD feel better after they use light therapy.
https://en.wikipedia.org/wiki/Seasonal_ … e_disorder
6 Types of Light Therapy for Seasonal Depression

elderflower · 2018-04-15 04:44:41

Transit ships using spin gravity have to be quite large to allow slow rotation. A small ship would have to spin fast which would generate considerable gyroscopic effects and probable sickness akin to sea sickness.

RobertDyck · 2018-04-15 07:11:15

elderflower wrote:

Transit ships using spin gravity have to be quite large to allow slow rotation. A small ship would have to spin fast which would generate considerable gyroscopic effects and probable sickness akin to sea sickness.

No
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GW Johnson · 2018-04-15 11:25:52

Don't get wrapped around the axle on how big or little long-term spin gravity designs can be. Those answers are already known. The equation (in consistent measure units) is a = R w^2, or acceleration (radial, not tangential) is proportional to spin radius and proportional to spin rate (angular velocity) squared. You get 1 gee at a 56 m radius at w = 4 rpm, which are not all consistent units.

For very long term exposures, the human balance organs in the ear imposes an angular rate maximum of something near 4 rpm. It's fuzzy, might be 3, might be 5. With training and acclimatization, certain individuals genetically endowed with the right characteristics might endure (long-term) almost twice that rate, maybe right near 8 rpm. But most people are limited nearer to 4 rpm, excepting only short exposures. Choosing the max 4 rpm sets your min spin radius requirement at 56 m. Period.

I'm not sure, but I think there might be a blood-pooling-in-the-legs head-to-toe pressure gradient problem leading to fainting at something around 12 rpm, but this is suitable only for short exposures. That would be for standing persons. Being seated relieves some of it, allowing higher spin rates, but again only for temporary exposures. Lying prone relieves that problem, allowing higher spin rates still, but again only for temporary exposure.

The one way trip is months long. Not "temporary exposure" at all. You are looking at max 4 rpm, and thus min 56 m spin radius, for one full gee. Why 1 full gee? That is what we evolved in, and thus it is the only level we ALREADY KNOW will work for long term health.

We CANNOT ETHICALLY LOWER THAT until we have gained the experience to actually know what benefits partial gee confers. Since we were too stupid to study this the last 4 decades in LEO, we have to learn while going to the moon and Mars. So we go at 1 gee. Nothing else is ethical at this time.

Now, the spin gravity vehicle design problem thus boils down to two choices: (1) do we use rigid spinning structures? or (2) do we do cable-connected spinning structures? The answer depends ONLY on how long a delay you want to tolerate, in order to develop the requisite flight hardware to the point where we can trust it outside of LEO. That is a high bar.

Cable-connected spinning structures have never before been done ROUTINELY except as a tether ball game. None have ever flown in space except as one experiment during the Gemini program that produced only ten-thousandths of a gee. This design approach is still utterly immature from a technological standpoint. No flying hardware, only papers in the literature. No reputable engineer would EVER recommend doing this without SOME YEARS of development in experimental flying hardware in LEO, where fast bailout is possible.

Rigid spinning structure dynamics are well-understood and well-defined, and supported by over two centuries of experience! This started with the flywheels, cranks, and connecting-rod structures of steam-powered equipment. Its widest routine application today is automotive wheels and the equipment that balances tires. THIS is a technology mature enough to support a rapid flight demonstration in LEO, in turn enough to support its use flying to Mars or anywhere else.

THAT is why I recommend rigid spin gravity structures over cable-connected spinning structures. I don't want to wait another 20 years or so, getting the technology mature enough to use outside LEO. Rigid stuff could be made ready in a year or three.

So how do you do 56 m radius rigid stuff without breaking the bank building "battlestar galacticas" over 100 m in diameter? Simple: don't spin about the long axis like a rifle bullet (what almost everybody envisions), spin about the shortest lateral dimension like a baton-twirler's baton. Both are quite stable.

And you don't have to build giant wheels, either (which is what most of the rest of folks envision). Most affordable structures tolerant of large applied thrust forces (unlike a space station !!!) are going to be roughly-cylindrical objects with a length to diameter ratio between 4 and 12.

4 is too small to benefit enough from the spinning baton effect, and 12 is getting too flimsy in bending strength to survive the spin-up and spin-down transients, without adding too much weight for extra structural beef. Something like 8-10 will probably prove out to be the best trade-off, but that's just my gut hunch.

It's those considerations that led me to the orbit-to-orbit transport design I posted about, over at "exrocketman" as "Mars Mission 2016". Spin gravity designs based on already-mature technology are inherently more compatible with mission designs based around an orbit-to-orbit transport, but you can do this in other mission design approaches. It's just not quite as easy. I like “easy” best of all, by the way.

Furthermore, Musk could easily do baton-type spin gravity by sending two BFS's on a mission (something he already plans to do), docked tail-to-tail like they already intend to do for refilling, and then spin this cluster end-over-end (something he hasn’t thought about yet, at least not publicly).

The BFS length dimensions are large enough to get near 1 gee in each passenger space, at less than 4 rpm spin. You could spin up and spin down with the attitude thrusters, although the propellant quantity is not insignificant to do so. That’s just the price you pay. So plan on it.

There is NO logical reason not to do this, for almost any Mars mission scenario. Ethics demands it.

GW

RobertDyck · 2018-04-15 12:10:22

Gemini 11. September 12 to 15, 1966.

Oldfart1939 · 2018-04-15 15:42:10

I'm going to agree in general principle that some form of gravity MUST be provided for the Marsonauts, although I somewhat disagree that we need a full 1 g on the outbound flight to Mars; in that case, I believe it would be ethically acceptable to utilize 0.38 g for adaptation to where they will be living for the next 18 months (or forever, in some cases). The gradual increase to 1 g on the return flight to satisfy the circulatory and respiratory systems ability to withstand the potential 11 g reentry to Earth is also prudent, not to mention having the ability to walk immediately upon return.

I'm not aware of any studies published on the short term effects of lunar gravity on the Apollo astronauts. This necessary study is probably one of the few justifications for having a lunar base, other than setup and operation of massive telescopes and radio telescopes on the reverse side of the Earth's only large natural satellite. The conjecture that having a lunar base as a stepping stone to Mars is preposterous, and fuel production utilizing "lunar water resources," those which are strictly based on indirect evidence, is equally questionable.

SpaceNut · 2018-04-15 16:45:35

We have also been on the ISS for a couple of decades now and we have not done the studies on how gravity effect virus or bacteria as well and these do have a huge impact on man's wellness..

Oldfart1939 · 2018-04-15 16:58:30

SpaceNut-

I suspect that the initial Mars research outpost will be similar to Antarctica, where common communicable diseases are almost unknown, due to the relative isolation and harsh outside environment.

louis · 2018-04-15 17:19:13

You make a good point SpaceNut, especially as we have probably at least the same number of bacteria inside and on us as the number of our own cells! There's likely a couple of kgs of bacteria in our gut and their disposition could well be affected by zero G.

Fact of the matter is there's a lot we don't know, but we do know that all astronauts make a pretty good recovery from prolonged zero G exposure.

SpaceNut wrote:

We have also been on the ISS for a couple of decades now and we have not done the studies on how gravity effect virus or bacteria as well and these do have a huge impact on man's wellness..

Oldfart1939 · 2018-04-15 22:37:30

A couple kgs of bacteria in our guts? Nope. Maybe a few grams in a room filled with people. I grew a 12 liter fermenter filled with bacteria that took 10 days before "harvesting" and it was only maybe 50 grams of solids. From that "harvest," we collected a few hundred milligrams of the desired enzyme. But to get an update, I'll ask my son, since he grows bacteria for his living, in the course of preparation of proteins for drug research.

Last edited by Oldfart1939 (2018-04-15 22:38:28)

louis · 2018-04-16 03:12:18

I should perhaps have put "up to"....

https://www.nih.gov/news-events/news-re … akeup-body

Some estimates suggest 1-3% of body weight is bacteria. So in a 200 pound adult 3% would be up to 6 pounds and from everything I have read, the vast majority would be in the digestive system. However, estimates vary a lot, so could be more or less.

Oldfart1939 wrote:

A couple kgs of bacteria in our guts? Nope. Maybe a few grams in a room filled with people. I grew a 12 liter fermenter filled with bacteria that took 10 days before "harvesting" and it was only maybe 50 grams of solids. From that "harvest," we collected a few hundred milligrams of the desired enzyme. But to get an update, I'll ask my son, since he grows bacteria for his living, in the course of preparation of proteins for drug research.

elderflower · 2018-04-16 05:03:42

I'm not sure you are talking about the same things. It sounds like Louis is referring to wet bacteria and Oldfart to dry matter.

louis · 2018-04-16 07:04:38

Well we weigh our "wet" selves, so yes, I guess wet bacteria!

elderflower wrote:

I'm not sure you are talking about the same things. It sounds like Louis is referring to wet bacteria and Oldfart to dry matter.

tahanson43206 · 2018-11-14 12:21:20

SearchTerm:SeasonalDepression

SpaceNut, a local radio station ran an interview with a doctor who recently published a book about depression, how to recognize it, and how to deal with it.
While the subject of the interview was seasonal depression due to the time change, it occurred to me that reduced sunlight might be a negative factor for susceptible human beings, and that countermeasures would seem advisable for Mars or any other location where "normal" sunlight patterns are not available.

I was reassured to see that you (and others on the forum) have already discussed this concern.

SpaceNut wrote:

There is something else in the winter, that is seasonal depression and at appears to be a factor for those that come from a warm sunny climate to the station. The experiment can be altered since we have lights now for that seasonal depression due to the extended winter.
People use light therapy to treat seasonal affective disorder (SAD), which is depression related to shorter days and reduced sunlight exposure during the fall and winter months. Most people with SAD feel better after they use light therapy.
https://en.wikipedia.org/wiki/Seasonal_ … e_disorder
6 Types of Light Therapy for Seasonal Depression

SpaceNut · 2018-11-14 18:26:48

We know that the maximum solar irradiance on Mars is about 590 W/m2 compared to about 1000 W/m2 at the Earth's as recieved on the surface from the sun for each. This does very over the length of mars elongated orbit.
If you are on earth at 36' you would be at the same light level as mars.

Mars_B4_Moon · 2022-05-03 09:45:03

Europe Cancels Joint Moon Missions with Russia
https://www.scientificamerican.com/arti … th-russia/

'The following is the prepared text for my address to the Oxford Union , Oxford UK, on the evening of 3 February in support of the proposition, This House Would Populate Mars. The Oxford Union is the world’s foremost debating society.'
https://www.forbes.com/sites/gregautry/ … on-debate/
“This House Would Populate Mars!” I doubt there has ever been a bolder proclamation made in this historic hall. I am so honored to be standing here in support of it!

tahanson43206 wrote:

SearchTerm:SeasonalDepression

I was reassured to see that you (and others on the forum) have already discussed this concern.

Now imagine a futurist 2001 Space Odyssey style mission to Europe or Titan, people are expected to spend 3-5 years in a large tin can

Mental Health, people who live on subs might have the right stuff? but when you are breaking down do you know it? would an AI doctor be useful to study a person, in Japanese society people sometimes live isolated hermit lives inside big cities, order pizza nododles, chat to their friends on some playstation gamer gizmo ap, some hold jobs, some work part time, some are out of work, maybe the lifestyle works in such a neo Tokyo concrete society and inside such crowded conditions?

When mental conditions break down so will the work and repair?
technicians working on a fire-suppression system at an Antarctica scientific station were found unconscious and died.
https://apnews.com/article/antarctica-f … b0c0a5eba5

Pilot error lack of sleep?

Bad Sleep? fatigue led to deadly Ga. jet crash
https://www.washingtontimes.com/news/20 … -to-crash/
Federal investigators say a pilot failed to follow procedures during landing, and that fatigue from lack of sleep contributed to a fiery jet crash
https://www.foxbusiness.com/markets/pil … ing-factor

and overseas Air France flight AF447 took a break, Error inputs on sensors? After waking the pilot from his sleep, the co-pilot remained at the controls and raised the angle of the plane's climb until it stalled three times and finally fell into the ocean

Murder on the Outpost
https://bookstr.com/article/scientist-i … k-endings/
Scientist in Antarctica Stabs Colleague for Spoiling Book?

https://www.mirror.co.uk/news/world-new … e-13470907
Russian researcher in Antarctica that snapped and stabbed and critically wounded a colleague. Claimed he was "Driven mad by living in confined space."

Last edited by Mars_B4_Moon (2022-05-03 09:57:48)

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