I like it! But the ACTION in the second half can be stronger. Right now it only gives us her psychological growth, not a visible (filmable) action. Of course, short films are more flexible, and perhaps the climactic scene is about just that: her acceptance...
In any case, try the Logline Generator (link above), and you'll see that the better version of this logline might be along the lines of:
When sent a package containing her boyfriend’s belongings, a conflicted lover must uncover the cause of his disappearance; but when she learns he willingly vanished to pursue space travel, she must embrace selflessness and accept his decision BEFORE [Final Action].
I still think that there could be a final action that SHOWS her transformation.