Delta IV Heavy Upgrade 53 t

American orbital launch vehicle. Proposed upgrade to Delta IV Heavy by clustering five common booster modules, using 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. Payload fairings over 6.5 m diameter could be accommodated. Introduction would require new launch pads and booster assembly infrastructure.

LEO Payload: 48,000 kg (105,000 lb) to a 407 km orbit at 28.50 degrees. Payload: 18,000 kg (39,000 lb) to a earth escape.