I was wondering if the human body could withstand long term (as in months, years) of more than 1g accleration to speed up crewed missions to planets in our solar system. It turns out that its extremely harsh on our bodies and ages them significantly (see below). What methods could be used to alleviate this problem, could you be protected by being submerged in water for example.

• The human body can tolerate violent accelerations for short periods, i ncluding the prolonged high-g acceleration necessary to reach Earth orbit. However very prolonged periods of high-g acceleration during travel between planets would be very harmful to the body, and therefore out of the question *

• Imagine traveling to Mars, accelerating all the way at 3 gravities. You would weight three times your normal weight for the duration of the trip and would barely be able to move, but what would the unrelenting acceleration be doing to your body? Heavy acceleration is a speeded-up aging process. Tissues break down, capillaries break down and the heart has to do many times its proper work. You could not count on being in good shape when you arrived *

Cymek said:

I was wondering if the human body could withstand long term (as in months, years) of more than 1g accleration to speed up crewed missions to planets in our solar system. It turns out that its extremely harsh on our bodies and ages them significantly (see below). What methods could be used to alleviate this problem, could you be protected by being submerged in water for example.

• The human body can tolerate violent accelerations for short periods, i ncluding the prolonged high-g acceleration necessary to reach Earth orbit. However very prolonged periods of high-g acceleration during travel between planets would be very harmful to the body, and therefore out of the question *

• Imagine traveling to Mars, accelerating all the way at 3 gravities. You would weight three times your normal weight for the duration of the trip and would barely be able to move, but what would the unrelenting acceleration be doing to your body? Heavy acceleration is a speeded-up aging process. Tissues break down, capillaries break down and the heart has to do many times its proper work. You could not count on being in good shape when you arrived *

Conversely long periods of near zero g would be beneficial?

You wouldn’t need to accelerate much more than 1g. Maybe do a quick burst higher than that to start off with but even accelerating at 1g you would be going pretty fast before too long…

furious said:

You wouldn’t need to accelerate much more than 1g. Maybe do a quick burst higher than that to start off with but even accelerating at 1g you would be going pretty fast before too long…

Yes, if you accelerated at 1g for 1 year, you would end up at just over the speed of light, if it wasn’t for those damned relativistic effects.

The Rev Dodgson said:

furious said:

You wouldn’t need to accelerate much more than 1g. Maybe do a quick burst higher than that to start off with but even accelerating at 1g you would be going pretty fast before too long…

Yes, if you accelerated at 1g for 1 year, you would end up at just over the speed of light, if it wasn’t for those damned relativistic effects.

You can accelerated at 1 g for 1 year (or indefinitely).

Your speed relative to any other FoR will never exceed c.

Cymek said:

I was wondering if the human body could withstand long term (as in months, years) of more than 1g. It turns out that its extremely harsh on our bodies and ages them significantly (see below). What methods could be used to alleviate this problem, could you be protected by being submerged in water for example.

• The human body can tolerate violent accelerations for short periods, i ncluding the prolonged high-g acceleration necessary to reach Earth orbit. However very prolonged periods of high-g acceleration during travel between planets would be very harmful to the body, and therefore out of the question *
  

The real issue here is living on a super-Earth type planet. Science fiction authors have considered this many times. For example from “First Lensman” by E.E.(Doc) Smith

“Funny about Valeria, isn’t it … But wherever diamonds are, there go Dutchmen. And Dutch women go wherever their men do. And, in spite of medical advice, Dutch babies arrive. Although a lot of the adults died, three G’s is no joke, practically all of the babies keep on living. Developing bones and muscles to fit, walking at a year and a half old, living normally, they say that the third generation will be perfectly at home there. Which shows that the human animal is more adaptable than some ranking medicos had believed.”

In the shorter term, a few months or so, three G’s can be handled by people lying down easily, sitting with more difficulty. For standing and walking, a powered exoskeleton would be needed. Preparation in the form of weightlifting would be a very big help. This would also include wearing a weight belt when going about normal tasks before flight. Training will increase bone mass and muscle strength.

“A G-suit is worn by aviators and astronauts who are subject to high levels of acceleration (‘G’). It is designed to prevent a black-out and g-LOC (gravity-induced Loss Of Consciousness), due to the blood pooling in the lower part of the body when under G, thus depriving the brain of blood. The resting g-tolerance of a typical person is anywhere from 3-5 g depending on the person. A g-suit will typically add 1 g of tolerance to that limit.”

Perhaps over-simplistic, but the variation in body mass for people with similar skeleton size probably exceeds a factor of 3, so the people at the light end of the range could presumably withstand long-term 3g with no more ill effects than those experienced by people at the heavy end under 1g.

The Rev Dodgson said:

… with no more ill effects than those experienced by people at the heavy end under 1g.

And also no less ill effects.

The Rev Dodgson said:

The Rev Dodgson said:

… with no more ill effects than those experienced by people at the heavy end under 1g.

And also no less ill effects.

With a lot more muscle growth stimulation.

The Rev Dodgson said:

Perhaps over-simplistic, but the variation in body mass for people with similar skeleton size probably exceeds a factor of 3, so the people at the light end of the range could presumably withstand long-term 3g with no more ill effects than those experienced by people at the heavy end under 1g.

I don’t think so. Your retinas will be damaged, your internal organs will start to separate. People can stand 3 g for a short period, lying down.

dv said:

I don’t think so. Your retinas will be damaged, your internal organs will start to separate.

Do we have good evidence of these effects, or are they hypothesised based on extrapolated data or similar?

A detailed structural analysis of the human body under 3g would be QI.

dv said:

People can stand 3 g for a short period, lying down.

But can they lie 3g for a short period, standing up?

The Rev Dodgson said:

dv said:

I don’t think so. Your retinas will be damaged, your internal organs will start to separate.

Do we have good evidence of these effects, or are they hypothesised based on extrapolated data or similar?

A detailed structural analysis of the human body under 3g would be QI.

dv said:

People can stand 3 g for a short period, lying down.

But can they lie 3g for a short period, standing up?

Ha ha

The human body can withstand high gs for very short periods of time..

Explosive seat ejection from aircraft… 15g

In a crash… 100g

https://en.m.wikipedia.org/wiki/Orders_of_magnitude_(acceleration)

too much stress on the heart id say

I’d give you a few weeks