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SpaceX hits new Falcon 9 reusability milestone, retracts all four landing legs

SpaceX appears to have selected Falcon 9 B1056 to become the first booster to have all four landing legs retracted and stowed. While relatively minor in the scope full Falcon 9 booster reuse, in-situ leg retraction could save SpaceX days of recovery and preflight work, a big help for truly rapid reusability.

A handful of prior retraction attempts have been made on Block 5 boosters but unknown issues prevented the process from taking hold. With some modifications to the legs and their deployment/retraction mechanisms, SpaceX seems to have solved those issues and is ready to graduate to a new level of rapid and easy rocket reusability. Teslarati photographer Tom Cross was on site in Port Canaveral, Florida when SpaceX began its first operational leg retractions and was able to capture photos and videos of the process.

The crux of the need for a relatively complex crane-and-jig method of leg retraction rests on SpaceX's landing leg design. Put simply, after rapidly deploying with a combination of gravity and hydraulics, Falcon 9 landing legs have no built-in way to return to their stowed state. Each of the four legs are quite large, weighing around 600 kg (1300 lb) and stretching about 10m (33 ft) from hinge to tip. They use an intricate telescoping carbon fiber deployment mechanism to give the legs enough strength to stand up to the forces of Falcon 9 booster landings.

Combined, the legs' size and telescoping mechanism makes the addition of an onboard retraction mechanism impractical. All the needed hardware would struggle to find a good place for installation and would quite literally be dead weight during launches and landings, stealing from Falcon 9/Heavy payload capacity and generally serving no purpose until a booster has been lifted off the ground with a giant crane.

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