Another study just confirmed how damaging is the lack of gravity for astronauts. It can disrupt the flow of blood in dangerous ways:
"Assessment of Jugular Venous Blood Flow Stasis and Thrombosis During Spaceflight"
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2755307I think that
SpaceX (with NASA jumping on board as soon as it realizes that Musk is really going to be able to send the first humans to Mars)
will indeed send the first humans to Mars, not on 2024-2025, as Musk is aspirationally wanting, but possible before 2030.
But they will reach Mars on a debilitated health condition, with their immune system and vision affected and probably also with some small mental problems because of radiation exposure during the voyage.
After 6 months on gravity 0, they will also have muscular and bone problems, but, actually, Mars will help them on this.
When returning Earth, after 6 months on International Space Station, astronauts normally can't even stand up, much less walk on their own.
But humans on Mars will have to deal with only a third of the normal gravity, thanks to the low gravity of Mars. So, probably, even if with some problems, they will be able to walk and work in Mars about one year until the next window of Mars-Earth proximity in order to return to Earth.
However, even if, on a technological level, everything works according to plans, they will arrive Earth with very serious health problems. Wouldn't be surprised that some of them would die or would have permanent health conditions because of the voyage, beside the very increased risk of cancer.
But I agree that Musk won't have a lack of voluntaries to go. He can pay with glory and money all their health problems.
And
Musk already left clear that the health of the first humans on Mars won't be a major concern."Elon Musk: First humans who journey to Mars must 'be prepared to die"
https://www.theverge.com/2016/9/27/13080836/elon-musk-spacex-mars-mission-death-riskAnd taking in account that we are talking about the most remarkable achieve on humankind history I have to agree with him. Their life must be a major concern, their health, not really.
By the way, for the reasons I wrote here
https://bitcointalksearch.org/topic/m.29108349, I have serious doubts that there are any technological developed alien civilizations on our Galaxy. Science fiction assumed we were common beings, but it seems
we are probably not only the most extraordinary being on the all of the galaxy, but the only real extraordinary being.So, no problems from this perspective. No alien first contacts, except with unicellular beings and the occasional planet with complex basic animals. The Milky Way will be our backyard for us to take.
If that wasn't the case, we would see traces of any alien civilization all over the galaxy.
And Starship will cross the Van Allen Belt very fast. This isn't the problem, as long as there is no solar storm, but the other 6 months of exposure during the voyage:
https://en.wikipedia.org/wiki/Van_Allen_radiation_belt#Implications_for_space_travelhttps://www.space.com/33948-van-allen-radiation-belts.html"The astronauts on the ISS do not regularly spend time inside the belts, but from time to time solar storms expand the belts to the orbit of the space station. In the 1960s, several Apollo crews went through the Van Allen belts on their way to and from the moon. Their time in that radiation-intensive region, however, was very short, in part because the trajectory was designed to pass through the thinnest known parts. With more study, astronauts can be better protected for long-term stays in Earth orbit."