This is the place where this draft of the story is going to be most different from the last one. Having created a new main character and put him in the same situation, his crisis is different and the resolution has to be different as well. This character simply doesn't care about the things that were important to the previous one. But his problem is the same: Earth is threatened, but he has more important things to defend.
Last time I came >this close< to destroying the Earth at the end of the story. It could still happen.
I wrote up a thousand words of notes about what might happen at the climax. A key piece of broken equipment could be repairable or not, and there are two separate pieces of information the character could choose to lie or tell the truth about, which creates eight possibilities. I wrote up a paragraph or two about each possibility and the most dramatic things that could happen as a result. (Yes, this is how I write. Could have been worse -- I seriously considered drawing up a decision tree.)
Several of the possibilities make no sense. One leads to a straightforward heroic ending, which is satisfying in a conventional way but I want more moral complexity from this story. Two lead to ironic downer endings, which I don't want either. But two of them lead to unconventional endings with a twist in the tail, one of them more straightforward than the other. That's the one I'm now driving toward. However, I may change course as the climax shapes up. (And I can go back and change the lead-in if that would make a better ending.)
A snippet: "I tried to place an urgent call to Merganther, on Funnel One, but the quantar link was down again -- it had become more and more cranky as years wore on without proper replacement parts -- and the radio was even more badly shredded than usual by Earth's magnetic fields. All I could hear was the roar of static and occasional snatches of words."
Oh, also: today's email brought a rejection from Fantasy, and a note from the editor at Tor that he has no idea how long it will take the publisher to come to a decision about my novel. The rejected story will go right back in the mail just as soon as I decide where to send it next; the nails will continue to be bitten.