1K is not absolute zero, 0K is. 420K is 150°C, barely above boiling.

In space, your temperature may range from 0.01K to over 2000K depending on solar radiation levels over the spectrum.

You're exposed to higher levels of radiation and vacuum will tear at organic structures.

A tradigrade can probably survive a trip to mars if they're very lucky. Better to send a huge amount of them, maybe one makes it.

But interstellar distances are too vast and the time taken is too long. The DNA within tradigrades, even when hibernating, will have been torn to shreds and with no energy to repair there is no way back to life from that.

I will quote form the article:

> Back on Earth, over 68% of the subjects protected from solar UV radiation were reanimated within 30 minutes following rehydration, although subsequent mortality was high; many of these produced viable embryos.

And that is after 10 days of exposure. If it was 400 years, it's unlikely that even 1 is able to reanimate.

The hydrates species fared much worse and hydrated is more likely the state of the tardigrade when they are blown into space, rather than carefully dehydrated.

Woops:

> Some of them can withstand extremely cold temperatures down to 1 K (−458 °F; −272 °C) (close to absolute zero), while others can withstand extremely hot temperatures up to 420 K (300 °F; 150 °C)[36] for several minutes, pressures about six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human, and the vacuum of outer space.[37] Tardigrades that live in harsh conditions undergo an annual process of cyclomorphosis, allowing for survival in sub-zero temperatures.

And we're not even talking about 400 years, we're often talking about tens of thousands