Solid Rocket Motors
Atlas V Launch Vehicle, Solid Rocket Motors
Used to increase engine thrust; 4 total on Mars Science Laboratory's Atlas V Launch Vehicle.
Four solid rocket boosters strapped onto the common core booster add to the thrust that will be produced by the first stage. Each of these boosters is 64 feet (19.5 meters) long and 61 inches (155 centimeters) in diameter, and delivers about 306,000 pounds (1.36 million newtons) of thrust.