[codewritinfool]

Well yeah, but it goes even deeper than that, IMO, since the domes could have just stayed on Earth. Why launch them into space and return them later? They're terrariums with all of the life support and lighting that they need.

[imglorp]

If you're making a backup ecosystem, you want it off planet in case the primary meets a nuke, asteroid, virus, etc. You could also park it in a stable solar orbit so it gets the right sun for its biostuff.

It seems there's no point sending it to deep space unless you're going to transplant it all on a new planet.