SpaceX CEO Elon Musk says that Starship’s Super Heavy boosters could forgo landings altogether, relying instead on a wild crane-based solution to recover the world’s largest rocket stage.
As discussed earlier in Teslarati, the Super Heavy Booster charged with carrying a ~ 1400 ton (~ 300,000 lb) starship around 25% of the way into orbit will be the largest rocket stage ever built – and by a wide margin.
“At the same height as an entire two-stage Falcon 9 rocket at 70 meters (230 feet) end to tail, the Super Heavy booster charged with placing the starship about a quarter of the way into orbit will be the biggest stage of rocket already built. Equipped with up to 28 Raptors capable of producing more than ~ 7,300 metric tons (~ 16.2 million lbf) of lift-off thrust, the Super Heavy will also be the most powerful rocket ever built, outperforming the Saturn V and Falcon Heavy respectively. SpaceX by a factor of more than two and three. “
Teslarati.com – December 29, 2020
Before today, December 30, SpaceX’s plan was to retrieve more or less Super Heavy boosters in a similar way to Falcon 9 and Falcon Heavy, landing them on an ocean platform or returning to land as close to the platform as possible. launch. Since the first iteration of SpaceX’s Mars rocket was made public in 2016, SpaceX and CEO Elon Musk have also maintained a consistent desire to land Super Heavy Boosters directly on top of the launch assembly after much refinement.
Recovering the launch assembly would require unprecedented precision and accuracy and add a new element of risk or the need for extraordinarily strong cushion hardware. However, the benefits would be equally significant, entirely eliminating the need for expensive recovery assets, time-consuming transportation and even the time it would take to hoist Super Heavy boosters back into the launch assembly of a landing zone adjacent to a platform. .
Instead, Musk says that SpaceX may be able to literally take Super Heavy in the air, grabbing the booster before it touches the ground, somehow fitting an elaborate “launch tower arm” under its steel grid fins. While such a solution seems as complex and risky as it may seem, it would technically make it impossible for any reinforcement recovery infrastructure to be needed – even including the legs that the Super Heavy would otherwise need.
Saves mass and cost of legs and allows immediate repositioning of the booster in the launch assembly – ready to refly in less than an hour
– Elon Musk (@elonmusk) December 30, 2020
While it is true, capturing the Super Heavy by its grid fins would likely require that the control surfaces and structures they attach to are substantially over-built – especially if Musk means that the crane arm mechanism would be able to pick up anywhere along of 7 m (23 feet) of the implanted fins) length. Even more importantly, it seems extraordinarily unlikely that such a complex and unproven recovery method can work reliably in the first or several attempts, implying that the first reinforcements will still need some kind of rudimentary landing pad.
In other words, much like direct mount landings for launch, recovery from overhead crane capture is likely not a feature that should debut in Super Heavy v1.0.