It starts out well, if you handwave the initial premise: the sun is dying, there's a crew piloting a ginormous bomb that's supposed to jump-start the sun again--the second one, after the first attempt failed for unknown reasons. The first, oh, twenty minutes or so are a pretty believable look at what it might be like to be stuck in a rather small space with a small number of people for years, knowing that you're humanity's last chance for survival. (Or something like that.)
And then they receive an automated distress signal from the first bomb/ship, and have the choice of trying to salvage the bomb. Which they do, but in the process there's a series of accidents, resulting in loss the oxygen garden and the captain. And when they arrive on board the first ship, they discover that it's been crippled, and they can't do anything with it.
(Apparently the captain of the first crew went crazy, and either killed his crew, or talked them into mass-suicide, which is believable, I suppose. Stuck out in space for that long, a man's liable to go a bit screwy.)
And there are more accidents, and a couple more people die. Still fairly believable, still fairly well-written. But it turns out that the crazy captain somehow survived, got onto the ship, and is trying to sabotage the mission and kill everybody. Basically, what starts out as a sci-fi psychological thriller turns into a slasher horror film.
So I was disappointed. Actually fast-forwarded through the last fifteen minutes or so, once it was obvious that they were going to die one by one.