The rocket launched at the beginning of the movie is a Viking rocket. According to "The Viking Rocket Story" by Rosen, a static test - where the rocket engine is fired but the rocket remains on the pad - went bad when the rocket left the launch pad completely out of control. Housing for the families of the workers was close enough to be within range. Luckily the rocket landed in the desert and did not hurt anyone.
The $5,000 each man is to be paid would equate to over $51,000 in 2022.
The canvas bags hanging on the front bumper of the three trucks contain water for the engine's radiator, if needed.
The two tank trucks are Kenworth 900 series. The other truck is a Sterling with a modified cab.