"It! The Terror From Beyond Space". From Wikipedia: "The plot involves a rescue mission to Mars that finds the sole survivor of a previous Earth expedition. The survivor, the expedition's former commander, claims that his crew were killed by a hostile Martian life form. The rescue ship's captain does not believe him, surmising that they were actually killed for their provisions so that the commander could survive. He confines the commander to quarters after the rescue ship launches for Earth. The same hostile Martian creature, now a stowaway and immune to the crew's ... weapons, begins another human hunting spree.
The premise of a hostile alien creature hunting a spaceship's crew as it returns to Earth was the inspiration for screenwriter Dan O'Bannon's screenplay for Ridley Scott's 1979 film 'Alien'."
One member of this second Mars mission's crew is named Bob. His efforts to deal with the alien threat place him in harm's way. At one point in the movie, one of the crew members asks, "What about Bob?" Of course, this is also a level name in Marathon 2.
The link is to a trailer. I recommend that you buy the movie on the cheep or rent it online. Its cheesy, but with the right combination of friends or family, popcorn or other treats and beverages, its guaranteed to entertain someone.