You have still failed to backup your assertations - please simply state what extremes of heat and cold they can endure. I seriously doubt they can survive the extremes temperature fluctuations required for space travel.
I think it's beyond argument that with enough "insulation" it should be possible for other forms of life to do so, especially mindless, soulless, Godless, pitiful, helpless little ol' archaebacter that can live on rocks!
I would direct your attention to spore forming bacilli that can endure hundreds of years at absolute zero (and temperatures of up to 212 degrees) in spore form and be restored to viability once conditions become suitable.