The BoeingDelta II family of launch vehicles has been in service for over 10 years and has successfully launched 90 projects including the last six NASA missions to Mars:
Deltas are expendable launch vehicles (ELVs), which means they are only used once. Each launch vehicle consists of:
Solid rocket motors: Used to increase engine thrust; 9 total, 6 of which are lit at liftoff, 3 a minute into flight
Stage I: Fuel and oxygen tanks that feed an engine for the ascent
Stage II: Fuel and oxidizer and the vehicle's "brains"; fires twice, once to insert the vehicle-spacecraft stack into low Earth orbit and then again to orient the third stage prior to it firing
Stage III: Solid rocket motor provides the majority of the velocity change needed to leave Earth orbit and inject the spacecraft on a trajectory to Mars; connected to the spacecraft until done firing, then separates
Payload fairing: Thin metal shroud or nose cone to protect the spacecraft during the ascent through Earth's atmosphere
