It's not NASA though, it's Youtube. Why does this video have to come down when there are other unofficial versions of this song that are allowed to remain with money to be made from the ads.
I rather suspect that it's NASA who are taking down this video, going by the book in terms of the original agreement to have it up for a year. When other put it back, it is likely that some will get taken down, and some will remain with ads.
I don't think this video is for making profit, but maybe this is the problem, and is what prevents Youtube from using it to generate revenue from ads once the year is up - it's on an official NASA sponsored channel.
I would have thought that David Bowie would have made a different agreement as it is likely to be interpreted as he is forcing it to be taken down, whereas he turns a blind eye to all the other versions of this song, some of which are also amateur cover versions uploaded by amateur singers.
Copyright law does a good job of making artists and media companies look like arseholes that have double standards, going after ordinary folk, yet turning a blind eye to the REAL misusers of their content.
It also seems that copyright lawyers have a new worry with the prospect of private space trips (or of course, a whole new money making field of litigation). It seems the fate of this video is tied to which part of the space station it was performed in, so if it had been performed in, say, the Russian sector, it could not be forced off the internet by US copyright law. In a private space ship, the lawyers will be facing a huge hurdle just to determine which country's copyright laws apply, and it may well end up as being too difficult to enforce copyright in the case of private space flight, although I doubt this is going to present much of a problem given the cost of a ticket, so wide scale copyright infringement should not be a worry.