Status: Study 1961. Payload: 520 kg (1,140 lb). Gross mass: 10,624 kg (23,421 lb). Unfuelled mass: 1,784 kg (3,933 lb). Height: 2.60 m (8.50 ft). Diameter: 2.85 m (9.35 ft).
It also provided the propulsion requirements for lunar launch through transearth midcourse corrections. The same basic engine would used as on the terminal landing module with the throttling feature removed and a radiation cooled skirt added to provide an expansion ratio of 40:1.