Model of the National Launch System (NLS) heavy-lift vehicles, ca. 1989. This model was made for DoD by NASA Marshall Space Flight Center model shop (Huntsville, Alabama).
Variants shown are NLS-1 (left) and NLS-2 (right). The STS model is included for scale.
NLS-1 would be equipped with (Qty.4) STME liquid-fueled engines and (Qty.2) SRBs. Payload capacity: 100,000 lbs to a 220 nautical-mile orbit (as anticipated for Space Station Freedom).
NLS-2 would be equipped with (Qty.6) STME liquid-fueled engines only. Payload capacity: 50,000 lbs to LEO as required by DoD for NRO missions.
Estimated development cost for the NLS was $10.5 to $12 billion, including new launch pads and $2 billion for the STME (Space Transportation Main Engine, 650,000 lbs of thrust). The NLS program (a.k.a. New Launch System) was terminated in 1991. Replaced by Boeing EELV, which used SSMEs.