Both exhaust velocity (Isp) and mass ratio drive the rocket equation. Also thrust/mass matters a lot for Oberth effect. Delta upper stage Isp is good, but mass ratio and thrust are not.— Elon Musk (@elonmusk) February 12, 2018
Both exhaust velocity (Isp) and mass ratio drive the rocket equation. Also thrust/mass matters a lot for Oberth effect. Delta upper stage Isp is good, but mass ratio and thrust are not.