/sci/ - Science & Math

>>15237061
Yeah. Centaur V is just a bigger version of the Centaur III. It's very efficient but it's under powered for its weight, so it has to stage at a much higher speed a lot further downrange. That's one of the big reasons why they have to use Smart recovery instead of something propulsive.

>>11135110
>>11135137
ULA’s choice of SMART over retro propulsion has got nothing to do with Vulcan’s diameter or number of engines and everything to do with it’s performance: Rockets that use retro propulsion impose large performance penalties on their first-stages because they have to stage early and preserve fuel for landing. Their are ways to mitigate this problem e.g. New Glenn first-stage’s planned gliding trajectory will allow it to stage at a higher velocity and carry relatively less fuel for landing than a Falcon, meaning less of a performance penalty due to reusability than the latter. SMART completely sidesteps this problem by ditching the 1st stage all together and preserving just the engine segment with parachute recovery. Therefore, SMART allows a partially reusable Vulcan to get the exact same performance as an expendable one because no fuel needs to be preserved and the NASA-derived heat shield allows the engine segment to be recovered at much higher velocities than a booster can withstand. SMART is particularly useful to ULA due to their use of the Centaur second-stage, which has unparalleled efficiency but low thrust; this means ULA’s vehicles have to stage at really high velocities, too high for booster recovery, to yeet Centaur far enough to reach orbit. Retro propulsive landing which requires slow, early staging, is therefore incompatible with ULA’s golden goose, making it a non-option for ULA.