The short answer is, yes.
When International Space Station (ISS) crew members Matthew Dominick, Michael Barratt, Jeanette Epps, and Alexander Grebenkin returned from a 235-day mission on Friday, October 25, NASA officials decided to hospitalize them all in a Pensacola facility. One astronaut (not named for privacy reasons) stayed overnight, while the others were treated and released sooner, and they were all reunited the following day for what was called "normal post-flight reconditioning."
Because this item made the news, we can assume that hospitalizing ISS astronauts right after landing is not normal. And whatever the issues were, they were resolved fairly quickly. But this incident brings up a larger question: will humans ever be able to live "normal" lives in space for missions lasting years or even lifetimes?
A study published in Nature Communications last June shows that astronauts' kidneys may be a weak link in the plans to send humans on long space flights or residences in space. It has been known for some time that astronauts who spend weeks or months in space are especially prone to develop kidney stones. Anyone who has experienced the agonizing pain of this condition realizes that it's one of the last medical problems you want to encounter in a place where going down the street to the hospital is just not an option. If the stone is large enough, anuresis (inability to pee) can develop, leading to a fatal case of uremic poisoning.
If I had to guess (and bloggers exercise that privilege all the time), I would say that the brief hospital stays may have been kidney-related, although it could also have been balance issues or other effects of long-term residence in space. In space, kidney stones have no preferred location to drift to, but once you are standing upright on the ground, they will tend to head toward the exit, so to speak, which is just where you don't want them to go. A well-equipped hospital can use lithotripsy (non-invasive technology to break up kidney stones) or endoscopic methods to clear the obstruction. The procedure is uncomfortable but usually has a good outcome. However, I doubt that the ISS is equipped for such procedures.
Even if kidney stones can be prevented, the Nature study showed that both microgravity and the galactic cosmic radiation that can't be practically shielded from in space can damage kidney function in other ways. In the words of Dr. Keith Siew, one author of the study, "If we don't develop new ways to protect the kidneys, I'd say that while an astronaut could make it to Mars they might need dialysis on the way back." Not an encouraging prospect.
The study showed that microscopic changes occur in the kidney tubules that do the filtering so necessary to the body's proper functioning. It's not clear how much damage is due to radiation and how much to microgravity, but both are present in space and neither can be avoided.
Anything worth doing involves challenges, and the problems of kidneys in space is only one of the manifold issues that astronauts face, up to and including sudden death in a collision with a meteorite. And with proper planning, it's likely that this specific health issue will yield to either pharmaceutical treatment or some other workaround to enable astronauts to spend the several years in space needed to get to Mars, which seems to be the next goal of the humans-in-space race.
But it's possible that something like the old 2001: A Space Odyssey suspended-animation process might come back if we can't find a way to keep a fully functioning human body going in the harsh environment of space.
That doesn't matter to some people. In 2013, an outfit called Mars One started selling one-way tickets to the Red Planet, and a surprising number of people signed up and paid the nominal reservation fee. Apparently, there were enough folks here on Earth who saw getting away from it all as far as possible was a better option than what they were doing. Mars One went bankrupt in 2019, so I suppose those one-way tickets may show up now and then on eBay, but otherwise won't do anybody any good.
The point of that story is that some people would, in principle, take any risk in order to do a historic thing like land on Mars. But these folks are clearly in the minority.
There is a body of thought out there that our species' ultimate destiny is to migrate to other planets and basically keep doing what the Europeans did in the Age of Exploration: find and exploit new uninhabited places to live. And it's always a bad idea to underestimate the ingenuity of humankind. Perhaps with some yet-uninvented technology and bio-modification of the human body, we could fix it so that millions of—somethings—could live on Mars. I say "somethings" because if you modify the human form so that it can live on Mars, would these beings be capable of moving back to Earth? Would they be permanent Martians rather that Earthlings? It's hard to say.
The reader may be able to tell that I recently read a copy of Ray Bradbury's story collection The Illustrated Man. Bradbury was not the least bit interested in the actual nuts and bolts of how to get to Mars. I've even read one critic who said Bradbury "hated" technology, but I think that's an exaggeration. What Bradbury used the trope of space travel for was to examine human relations—questions of racial discrimination, government, politics, and love. And he probably did that better than any other science-fiction writer of his day.
He also realized that no matter how far humanity travels, we will carry the same old baggage of what the theologians call original sin with us. And if people think that we could solve all our cultural and political problems simply by starting over on Mars or some yet-to-be-found planet, instead of spending billions on preventing kidney problems in future astronaut populations, they should read The Illustrated Man and realize that whatever problems space travel will fix, original sin isn't one of them.
Sources: I referred to news items on the ISS astronauts' hospitalizations at https://apnews.com/article/nasa-astronauts-spacex-splashdown-f99e1724b4c131e68e0cf8c30274fc11, https://nypost.com/2024/11/02/us-news/nasa-spacex-must-maintain-focus-after-astronauts-hospitalized-safety-panel-says/, and https://nypost.com/2024/10/26/us-news/nasa-astronaut-remains-in-the-hospital-after-returning-from-an-extended-stay-in-space/. A University College London article describing the Nature Communications study is at https://www.ucl.ac.uk/news/2024/jun/would-astronauts-kidneys-survive-roundtrip-mars, and the Nature article is at https://www.nature.com/articles/s41467-024-49212-1. The news of Mars One's bankruptcy is at https://www.theverge.com/2019/2/11/18220153/mars-one-bankruptcy-bas-lansdorp-human-settlement.
