One thing just hit me after three viewings and one reading: Grace didn't even think to ask Rocky if there was anyway he could survive on his planet.

I always thought it was a little weird that Grace didn't ask Rocky if he had some spare fuel in that giant ship that he could have. But I just now thought: he knew Rocky was a brilliant engineer, he didn't even think (unless I missed it) to ask "Just wondering, you think I can stay over at your place for a while?"