This title needs a little clarification, since there are no less than four films from 2011/12 that tell the story about Japan's mission to send a probe to an asteroid, collect samples, and return it to Earth. This film is the one called just "Hayabusa" and shouldn't be confused with (take a deep breath now) "Hayabusa: Back to the Earth", "Okaeri Hayabusa", or "Hayabusa: Harukanaru Kikan". Three of them are feature films while "Back to the Earth" is a feature-length documentary.
I don't know if I'll watch any of the others because I suspect if you've seen one, you've almost certainly seen them all. And watching this film, I'm reminded of how sentimental Japanese films can be. The main character, Megumi Mizusawa, is an astronomer because of the influence of her deceased elder brother, and this is referenced several times throughout the film.
Meanwhile, the story is one of success against the odds. The space probe went through a number of technical problems during its journey, solved by an ingenious bit of reprogramming, or by simply spamming the probe on different radio frequencies until they get lucky and it responds.
Its a nice story, and it works well on the big screen. The project lasted many years, so people left and people died, which gives the writer plenty of opportunity for sad scenes. I suppose I should be surprised the film doesn't include a romance. Although it does hint at one. Luckily, all the names have been changed, so no one can sue over misrepresentation.
In fact, each film version of this story contains characters with different names. It's tempting to watch them, just to see how they differ. Not very tempting, though.