I researched this a few years back, but memory is foggy.
IIRC, 24 humans have penetrated the Van Allen Belt to space and have been exposed to not only the trapped particles surrounding the Earth, but cosmic & solar radiation alike.
Not for weeks or months, but merely ‘days’. Researchers are devoid of any data whatsoever on the effects of long term exposure to solar & cosmic radiation, save for the experience of the Apollo missions (the oft-repeated citation, “They didn’t die.”).
From a scientific standpoint, it’s rather pathetic.
I still want to read the protocol and the results.
Do you know how much money was spent on this, and whose money it was?