I've heard a few complaints about present tense and while I agree for the most part, I want to point out some possible situations when it might be appropriate.
Personal Logs - If a character is keeping an ongoing personal log, they MIGHT use present tense. this is not the writer's doing, but the character's choice of writing her log.
Desperation - When a character is in a situation where death is assured, they MIGHT move from the death-confirming tone of past to the "I'm still alive" tone of present... just to give them hope and confidence.
Digital Action Recording - Ok, I just made this up. But if a character is implanted with a thought/action recording device (hey, this IS a sci-fi forum) then their notation MIGHT be present tense by default based on the chip manufacturer.
Just my thoughts.