Ideally, a rocket wants high thrust RP-1/LOX engines to lift off the ground and efficienct H2/LOX engines to accelerate into orbit. The MAKs Spaceplane got both in the RD-701, a rocket that used three propellants and five turbopumps for 350/460s Isp, https://t.co/ZxHqqISyA9 pic.twitter.com/s7kHShhqHb

— ToughSF (@ToughSf) April 24, 2019