I feel like if anyone wanted to avoid spoilers they'd have stopped reading this thread by now, but still [SPOILERS]
Honestly I'm a bit conflicted on a "happy" ending. From a story standpoint the ending works nicely. Either we confide in Sam and we can say they Sam was able to live their last days however they wanted, or we hide things from Sam and they live their last days in blissful ignorance. It's bittersweet and sad, but as the story said we did all we could. We can't evacuate the planet and smuggling Sam would be near impossible given everything is in lockdown due to all the damage and low rations.
However from a gameplay standpoint it feels like it falls short. We go into this game under the impression that as a player we make choices that will change the story, only to find out that no matter what we do the ending is mostly the same. We can't save Arbor or even help Sam in any way. What was the point of kissing up to Dr. Laine to get him to believe us if it doesn't change anything? Why should I as a player care about the choices I make if at the end of the day it's not going to matter? Arbor blows up and Sam dies, the end.
If anything, the endings could differ as so:
If we hid our results from Dr. Laine, then after the supernova happens both of us are held guilty for letting the supernova happen without doing anything.
If we tried to prove that there was an error in the code but Dr. Laine doesn't believe us, then when the supernova happens we get an "I told you so" moment with Dr. Laine. Or maybe Dr. Laine is tried for severe negligence while we are awarded for correcting the error and preventing something like this from happening again. We get those riches and acclaim that we were talking about with Sam, but it's a hollow victory since Sam's gone now.
Things like that. There is this part of me that is saying "yes, let me at least save Sam if I can't do anything about Arbor." but it's your story. At the very least I feel that there should be different endings like the examples above that help from a gameplay standpoint that would give the choices we make more meaning.