Atlas V 421

EELV

Mission Profile

The Atlas V 421 is a two-stage American medium-heavy lift launch vehicle featuring four solid rocket strap-on boosters and a single-engine Centaur upper stage with a 4-meter payload fairing, providing intermediate performance between the 401 and 431 configurations. Standing 58.3 m tall with a 3.8 m diameter and a liftoff mass of 408 tonnes, it generates 6,323 kN of combined liftoff thrust and can deliver 12,510 kg to low Earth orbit. First flying in October 2007, the Atlas V 421 has served national security and scientific missions requiring payload capacity between the standard single-booster and three-booster configurations, including the Mars Reconnaissance Orbiter's launch trajectory.