So one person is left to calculate a course change and it's implemented with zero x-checking by his team mates. I accept that this is a mcguffin to get people in to space suites but it's jarringly, blatantly stupid. Absolutely nothing would be done without following some procedure that required a sign-off by someone else. Or perhaps I'm just taking this too seriously?
First off, that's not what a McGuffin is. The word you were looking for is, simply, "plot device".
Secondly, Trey's team mates couldn't cross-check his calculations, because it's not their field of expertise. I guess in "normal" situations the procedure would have been that the crew would have consulted with the mission directors back on Earth, who (in case of agreement with the new plan) would have forwarded the calculation task to a dedicated team of specialised engineers/scientists on Earth, who in turn would have communicated their findings and calculation results back to Icarus; Trey would only have to implement the new settings into the ship's computer. However, since the Icarus had already come so close to the Sun that communication with Earth was not possible anymore (due to background noise/bad signal), they couldn't consult with Earth and hence Trey had to do the task alone, which task he accepted reluctantly (he was not happy with the decision to deviate from the original mission).
If there was any "blatant stupidity" in the movie, it was the captain's decision to stray from the original mission program and to spread their bets on two horses instead, because "two is better than one". But then again, hindsight is always 20/20.
hmmmm, perhaps I am a little lose in my use of the term McGuffin. Even though it seems to be defined as a plot device it should perhaps be more part of a story line than a single event. However I still think leaving one person to calculate the course change is wrong. Someone else would have reviewed the work or at least had him explain it to them - just as process to remove oversights. Also I would expect there to be a manual with a check list of all the steps required to make a course change - even if such an action was never planned. We've all seen so many movies and documentaries where there are always technical and procedural documents as actual printed manuals to be consulted. I bet even the Enterprise had a little library tucked away just off the command bridge in case of emergency.
A McGuffin is a particular type of plot device, not just any plot device. There are many types of plot device; for example, a deus ex machina is also a plot device.
I'd think it's better to leave the calculation to one specialist (or one specialist team) than to two non-specialists. And as already said, in normal situations, a team on Earth would be reviewing the work (made by a specialist or another team on Earth), but in this case the communication line with Earth was broken off.
Bear in mind, the other crew members had their own tasks and responsibilities that demanded their attention, they don't have time to get educated in Trey's field of expertise to the level that they could review and correct his work. Should Cora also have asked the others to check her (flawed) expert conclusion that there wouldn't be enough oxygen to complete the mission? Should Capa have asked the others to check his (flawed) expert conclusion that "two payloads are better than one"?
Yes, we've all seen so many movies and documentaries where there are always technical and procedural documents as actual printed manuals to be consulted, and surely the Icarus wouldn't have been any different. However, we've also seen many movies and documentaries of real-life events where technical procedures and checklists failed in some manner, either because the procedures/checklists fell short in detecting a certain fault/defect, or because human error simply "overruled"/"bypassed" the checklists (such as an airplane pilot checking off a certain item on a list, without actually checking the meter). In other words, a fault like Trey's isn't unrealistic at all, after all he and the crew are just human.
It makes a little more sense if you read the backstories that Danny Boyle wrote out for all the characters. Trey was a child prodigy who became an expert hacker - able to disable 12% of the world's computers for a day when he was only a teenager. He's also a control freak who opts to do everything himself rather than letting the Icarus computer do it. Trey was just overconfident and forgot one small detail - which is a very human thing to do. Humans make mistakes, even if they're on a spaceship. And that is why he's so horrified at it - because it's such a simple thing.
Agreed- the captain of the ship or his second in command should have enough knowledge to go over the calculations- after all that's why they were there! Kaneda should be expert enough to check wings with Trey, rather than leave him on his own. If anything, person in charge of mission should ALWAYS be the one signing things off, not letting everyone do whatever.
In the beginning there was nothing, and it exploded.