For the second time, SpaceX has removed the first potentially flightworthy Super Heavy from Starbase’s orbital launch mount – this time to reportedly make room for the installation of a pair of huge ‘Mechazilla’ arms.
Designed with three primary purposes in mind, SpaceX has decided to outfit Starbase’s Starship launch tower – an almost 500 ft (150m) tall framework – with three massive arms that CEO Elon Musk has informally deemed “Mechazilla.” The first of those arms is a relatively simple swinging structure that has already been installed on the tower and outfitted with a giant claw-like appendage. Once a few more parts are installed and a bit more plumbing completed, that “quick disconnect arm” or QD arm will help stabilize Super Heavy during Starship installation and connect the massive reusable upper stage to the pad’s tank farm and power supplies while still on the ground.
The star of the show, though, has always been a pair of even larger arms that are hoped to one day all SpaceX to catch Super Heavy boosters and Starships out of the air.
Of course, those catcher arms – deemed chopsticks by SpaceX employees – have more than one purpose. Likely explaining why they were ever considered in the first place, SpaceX’s Starbase launch site – situated walking distance from the Gulf of Mexico on the South Texas coast – was always going to have to deal with extreme weather and high winds on a practically daily basis. Additionally, conditions that are already disruptive at sea level become a near-constant nightmare for vertical launch vehicle integration, where Starship and Super Heavy are effectively hollow cylinders with extensive surface areas that need to be regularly and precisely manipulated 50-150m (200-450 ft) above the ground.
Already, SpaceX regularly has to halt work involving cranes and boom lifts at Starbase. For Starbase (Boca Chica) to ever be able to support regular orbital Starship launches, let alone the dozens to hundreds per year Musk has hinted at, cranes were never going to be a viable long-term solution for the all-weather capabilities and rapid reusability SpaceX requires. In other words, whether SpaceX ever actually manages to routinely ‘catch’ the world’s largest rocket booster and upper stage in the future, a tower with giant arms (or some other exotic crane-free solution) was always going to be needed at Starbase.
Mauricio, thanks for the shout-out. I got some great feedback from folks and updated this diagram once more. Added another @NicAnsuini photo to show the scale of these parts! pic.twitter.com/o54hdBITfL— LunarCaveman (@LunarCaveman) September 16, 2021
This is all to say that the Starship launch tower’s massive pair of arms – (in)famous for Musk’s plans to catch rockets – have a more immediate and guaranteed purpose: lifting, stacking, and otherwise manipulating Starship and Super Heavy in almost all weather conditions. Using tiny hardpoints located just under Super Heavy’s grid fins and (once installed) under Starship’s forward flaps, the chopstick arms will be mounted on a carriage that will attach to rails installed on the exterior of three of the tower’s arms. A complex system of cables, winches, motors, and pulleys will then attach to that carriage, giving the carriage and its arms the ability to move up and down the tower.
In theory, that means that the launch tower arms will be able to drop down, grab Super Heavy off of a SpaceX transporter, and lift it onto the orbital launch mount. Then, once the quick disconnect arm has swung into place and ‘grabbed’ Super Heavy’s interstage to secure it, the main arms will again drop down, grab Starship off of another transporter, and raise the 50m (~165 ft) rocket around 100m off the ground to install it on top of Super Heavy. Finally, the QD arm can then connect Starship to the pad systems.
SpaceX has been working around the clock on those chopstick arms for months. However, thanks to information shared by a forum member who visited Starbase and briefly chatted with one of the SpaceX technicians on-site, they might be almost finished. According to the employee they spoke with, SpaceX planned to temporarily remove Super Heavy Booster 4 from the orbital launch mount to make room for Mechazilla chopstick arm installation as early as this weekend (now come and gone) or next week. Mere days later, SpaceX returned B4 to a transport stand and moved the booster out of the way. In other words, having already been proven right with Super Heavy, it appears that SpaceX really does intend to install the Starship launch tower’s chopstick arms and carriage as early as this week. Stay tuned for more!