Maxim Brajlovsky: Easy as cake, huh?
Walter Curnow: Pie. Easy as pie.
Dimitri Moisevitch: I want to play a game with you, Dr. Floyd.
Dr. Heywood Floyd: I don't have time for games.
Dimitri Moisevitch: This is a good game. It's called "The Truth." For two minutes, I will tell only the truth, and so will you.
Dr. Heywood Floyd: Two minutes?
Dimitri Moisevitch: Two minutes.
Dr. Heywood Floyd: Make it a minute and a half.
Dimitri Moisevitch: One minute and three quarters.
Dr. Heywood Floyd: You start.
HAL-9000: What is going to happen?
Dave: Something wonderful.
HAL-9000: I'm afraid.
Dave: Don't be. We'll be together.
HAL-9000: Where will we be?
Dave: Where I am now.
Answer: If they didn't, any further manoeuvring would require much more fuel. They would be moving the mass of two ships.