Alejandro, I'm glad you are enjoying these as much as I enjoy making them for you. I apologize that they moved to another channel on KZfaq and sort of became hidden. The original sponsor of the videos put them on "hiatus" during the pandemic, but I personally wanted to continue producing them, hence they are now on my personal channel. More to come! Ron

[DATA EXPUNGED] , Thanks! Hopefully lots more to come. I try to keep the visuals coming at a pace that will hold viewers' interest. All done in Apple Keynote with the exception of a few movies where Keynote can't do want I want (which are few and far between!) If all you use presentation software for are bullet lists, you've lost the audience within minutes. Oh, yes, I also make extensive use of Affinity Photo to isolate objects from backgrounds, and generally improve images - great software - and unlike Photoshop, you don't have to rent it! Ron

Iophat, Check out the Wikipedia article on ion thrusters: en.wikipedia.org/wiki/Ion_thruster Yes, Iodine can be used and avoids all the cryogenic difficulties, but for some reason, it looks like Xenon is still the reaction-mass of choice (9 of 11 built so far). It looks like they are looking at other elements like Bismuth for future thruster technologies. I think that Xenon (and Krypton, and even Argon) is used because it doesn't mess up the engine being an inert gas. Thanks for the comment! I got to explore ion engines some more and learned new things. Ron