Delta IV Heavy Upgrade 42 t

American orbital launch vehicle. Proposed upgrade to Delta IV Heavy by adding new RS-800 engines to the core vehicles, an AUS-60 upper stage powered by 2 MB-60 or RL-60 27 metric ton thrust LOx/LH2 engines, and aluminum-lithium lightweight alloy in place of the existing aluminum in all stages. 6.5 m diameter payload fairing. Introduction would require modifications to existing launch pads.

LEO Payload: 38,000 kg (83,000 lb) to a 407 km orbit at 28.50 degrees. Payload: 14,000 kg (30,000 lb) to a earth escape.