Very unprofessional for a >1 trillion dollar expedition

Rating: 6/10 (11 August 2013)

I've watched this movie a few times. Visually, it is stunning. But the plot has so many holes it gives me a headache.
I think that a professionally run expedition would first orbit the planet for a while, collect data and plan their landing. But no, these guys descend to the planet immediately and take off for the alien spaceship. Once inside, one of the crew members takes off his helmet ignoring the fact that alien bacteria or viruses might be circulating in the air. Then, amazingly, the rest of the crew copy this stupid behavior.
David, the android in the crew, has no self-control, no judgment and is allowed to wander around unsupervised. Does the Weyland Corporation have any kind of quality control when building these androids? David causes the death of one of the crew by poisoning his drink with the alien DNA. He fiddles around with alien technology without any permission or supervision. He's so arrogant and foolish when dealing with the alien engineer that he gets his head ripped off.
The crew opens the door of the spaceship to any homicidal alien who happens to show up. This seems like poor security. It results in three or four deaths.
Two of the idiot crew members get lost in the alien spaceship and have to stay in it overnight until the weather outside gets better. During their sleep-over they encounter alien snake-like beings. But instead of running for their lives like people of ordinary intelligence, they decide to play pet the alien snake. They both die.
The geriatric corporate executive, Weyland, had developed the idea that the alien engineers can restore his youth even though there is no evidence whatever that they could or would. Weyland gets killed during his first encounter with an alien engineer.
Also, and this is typical of scifi movies, the aliens are very uncommunicative. But how can that be? Aren't they supposed to be an extremely advanced race? Couldn't they figure out how to talk to the Prometheus crew? Maybe they thought it was beneath them considering that the Prometheus crew seemed to be composed exclusively of morons.