Can humans ACTUALLY survive off-planet? What exactly is "space medicine"?

Ideas of space travel and colonies on the moon or Mars have gone from the realm of science fiction to possible reality as technology continues to advance.
But what if space kills? Mounting evidence shows that microgravity and cosmic radiation do serious damage to every aspect of our biology, damage that appears to be irreversible. Would the first humans headed to Mars arrive dead? Are we actually TRAPPED on Earth, so well adapted to its environment that we simply can't survive elsewhere? Is cryogenic hibernation the solution or just a desperate attempt to solve an unsolvable biological problem? Let's discuss! Readings to come!

An overview of the field
An overview of space medicine - British Journal of Anaesthesia

An overview of the effects of microgravity
The Effects of Zero Gravity

Living in zero gravity causes many changes to body | UCLA Health

And cosmic radiation isn't fun:
The Impact of Space Radiation on Brains of Future Martian and Lunar Explorers - Li - 2023 - Space Weather - Wiley Online Library

Radiation & Health: Humans in Space | American Council on Science and Health

The Cosmic Threat: How Cosmic Rays Affect Life in Space – Space Mesmerise