Note: this question uses third party worlds and species to illustrate the point, but it is not in any way about them, therefore this question is not off-topic. I checked.
I have just finished watching the new series Resident Alien, when a sudden thought hit me. That cold-blooded alien is standing completely naked in an environment that was cold enough to refreeze broken ice.
I thought it was odd until I realized this was not the first time something like this has happened. We have seen other aliens with reptilian or amphibian features and probably less than warm blood survive frigid climates that would naturally freeze a human seemingly unscathed, and a lot of the time without so much as a stitch of an environmental suit to offer any form of protection. Now once you take into account the dozens of icy moons and cold planets in our own solar system, it would seem that any cold-blooded traveler would need something to keep themselves warm if they land on the wrong kind of planet, since to do otherwise is a death sentence.
So here is my question: What technological solutions would a cold-blooded race of interstellar explorers use to keep themselves warm?