/sci/ - Science & Math

ATK’s bid for a EELV launcher from the mid 90/‘s. It lost to Delta IV and Atlas V. ATK’s EELV used the booster from a Titan IV as its first stage (SRMU), and had different variants
>Light
Used a Titan IV second stage on top of the SRMU and somethings a Star 48 solid rocket motor as a third stage to put 5 tons into LEO, 1.8 tons to GTO.
>Medium
Featured a new hydrogen oxygen second stage on top of the SRMU. The engine for that stage was the MB60, which was a derivative of the RL10 built by Mitsubishi in Japan. It could have a third stage; which was a Star 48 solid rocket motor. The medium variant could put 13.5 tons into LEO, and 4.5 tons into GTO
>Heavy
The biggest one. It used a trio of SRMUs as its first stage, although only the outer two would light on liftoff, and after their separation, the core SRMU would fire. It used the same hydrogen oxygen upper stage as the Medium variant. The Heavy could put 33 tons into LEO; and 14 tons into a GTO.