Long term space travel is hazardous to your health.  The destruction of red blood cells is a problem that will have to be solved before long term space living or missions to Mars and beyond are planned.

The human body evolved over a long period of time to live on this planet.  It wasn't made to live a long time in space.  So even if we can do it, should we do it?  Undoubtedly there will be volunteers to do it.  But enough to colonize Mars?

https://arstechnica.com/science/2022/01/we-dont-know-why-but-being-in-space-causes-us-to-destroy-our-blood/

Noel

I think that for longer stays in space there needs to be artificial gravity.  The lack of gravity may be what is causing the effect of more red blood cells being lost. 

In many sci-fi movies and tv shows you see spacecraft with a rotating section which produces centrifugal force to mimic gravity.

Dave

The concept of a spinning wheel space station was thought of a long time ago!

https://en.wikipedia.org/wiki/Rotating_wheel_space_station 

Didn't we have a spinning space wheel about 20 years ago for both astronauts and tourists?  Ya know, 2001: A Space Odyssey😏

10 hours ago, dave2013 said:

I think that for longer stays in space there needs to be artificial gravity.

One question might be "how much gravity do you need?" Is there a threshold or do you need full Earth gravity? Maybe Mars has enough gravity to avoid the problem.

11 hours ago, dave2013 said:

I think that for longer stays in space there needs to be artificial gravity.  The lack of gravity may be what is causing the effect of more red blood cells being lost. 

 

Very long stays in space yes, then there's an advantage to something like rotating crew quarters.  It is likely the lack of gravity that impacts blood vessels. Not required for a trip to Mars. 

We do stay on the ISS for months without long term issues. Longest is almost a year. 

With nuclear thermal propulsion and nuclear electric propulsion travel time is minimised. 3 months or less to mars. Or one month with nuclear electric. So impact on blood vessels and other physiological effects would be trivial. And of course medical science continues to advance and no doubt there will be therapies to assist. 

On something like Musk's Spaceship travel time is around 5 - 6 months. So again, not in zero G long enough to worry about blood vessels.

On Mars there is indeed a gravitational field, 38% of gravity on Earth. So I don't think cardiovascular and blood vessel issues would be too much of a problem if at all. 

Edited January 15, 20224 yr by martin-w

13 minutes ago, dmwalker said:

One question might be "how much gravity do you need?" Is there a threshold or do you need full Earth gravity? Maybe Mars has enough gravity to avoid the problem.

 

We don't have definitive data on that until we send people to Mars.

We can live for up to a year on the ISS without long term issues, so most experts are of the opinion that 38%  Earth gravity on mars should be sufficient.

Something like 21 months will be the initial duration for the first Mars visitors, in that time we should be able to gather enough data to make more definitive statements. 

4 minutes ago, martin-w said:

We do stay on the ISS for months without long term issues. Longest is almost a year. 

These published results are based on a six month period on the ISS so we need to confirm them and establish if there is a full recovery on return to Earth. So far, it seems that, even if full recovery occurs, it takes a very long time.

1 hour ago, charliearon said:

The concept of a spinning wheel space station was thought of a long time ago!

https://en.wikipedia.org/wiki/Rotating_wheel_space_station 

 

Yep, not a new idea at all. Certainly will be required for very long term (greater than a year) in space/orbit. One issue is nausea, in that a small centrifuge tends to be uncomfortable. We would need a very sizable rotating space station for maximum comfort in orbit. 

Incidentally, for long duration flights in Musk's Spaceship tethering two together a distance apart and rotating them is a concept under consideration. 

7 minutes ago, martin-w said:

We would need a very sizable rotating space station for maximum comfort in orbit. 

Perhaps, rather than a giant wheel design, as in 2001: A Space Odyssey, it could be a more compact cylindrical shape.

15 minutes ago, dmwalker said:

These published results are based on a six month period on the ISS so we need to confirm them and establish if there is a full recovery on return to Earth. So far, it seems that, even if full recovery occurs, it takes a very long time.

 

Yeah, back in 1987 two Russian cosmonauts spent 365 days in orbit, and they are still alive and kicking today. In fact I think all of the Russians who have spent 6 months to a year in space are alive and well. The famous Scott Kelly of course did, if I recall correctly, 350 says in 2015 with no long term issues. 

This is one research paper of course, so interesting, but research needs to be replicated, repeatable, a body of research before we can draw any meaningful conclusions. 

Edited January 15, 20224 yr by martin-w

4 minutes ago, dmwalker said:

Perhaps, rather than a giant wheel design, as in 2001: A Space Odyssey, it could be a more compact cylindrical shape.

 

Not sure if that would be feasible. In a cylinder the diameter is relatively small compared to the length of the structure. Ideally it would need to be more of a ring. Wide diameter and narrow. 

It doesn't have to be too complicated. Two spaceships tethered together and rotating would do the trick. 

https://www.techtimes.com/articles/262561/20210707/spacex-starship-two-tethered-spacecraft-launch-artificial-gravity-musk-reveals-purposes.htm

20 minutes ago, martin-w said:

Two spaceships tethered together and rotating would do the trick.

The word "tether" implies something flexible. Do you think that's what they mean?

1 hour ago, martin-w said:

if I recall correctly, 350 says in 2015 with no long term issues. 

That was only 6 or 7 years ago.  To determine long term effects you have study the astronaut's physicals for at least a couple of years.

I had a pulmonary embolism three years ago and my doctor orders a scan each year as well as an ultrasound of my upper thigh to check that there are no lingering blood clots and my lungs are still clear.

Noel

Edited January 15, 20224 yr by birdguy

43 minutes ago, dmwalker said:

The word "tether" implies something flexible. Do you think that's what they mean?

 

Yep. The centrifugal force keeps the tether taught.