SpaceX has the first grid fin for the next generation Super Heavy booster. The redesigned grid fins are 50% larger and higher strength, moving from four fins to three for vehicle control while enabling the booster to descend at higher angles of attack.
They’ll also be used for vehicle lift and catch, made possible by a new catch point addition and a lower positioning on the booster to align with the tower catch arms. Moving lower reduces the heat they receive from Starship’s engines at hot-staging and places the fin shaft, actuator, and fixed structure inside the booster’s main fuel tank.
New SpaceX Grid Fins Design
The redesigned grid fins for the next-generation Super Heavy booster (version 3) represent a significant evolution from previous versions.
Key technical details include:
– Reduction in number of fins: From four fins to three, arranged in a T-shape configuration (positioned at 90/90/180 degrees apart, with fins on the port, starboard, and non-tower/heat shield sides). Each grid fin weighs about 3 tons.
– Size and strength increase: 50% larger surface area and higher structural strength compared to prior designs.
– Relocation and integration: Moved from the interstage to the liquid methane (LCH4) tank, housed in pods welded to the tank wall. The fins are positioned lower on the booster to align with the tower’s catch as, with the fin shaft, actuators, and fixed structure now placed inside the booster’s main fuel tank. This also includes a new catch point addition for vehicle lift and catch operations.
– Slightly modified design for improved aerodynamics.
These changes enable:
– Enhanced descent control: The booster can descend at higher angles of attack (AoA), improving stability and precision during reentry and landing phases.
– Weight reduction: Eliminating one fin deletes unnecessary mass while ensuring all three fins remain in the airflow during glide-back and descent, optimizing aerodynamic efficiency.
– Improved reusability and catch mechanics: The lower positioning reduces heat exposure from Starship’s engines during hot-staging and facilitates direct catching by the launch tower’s “chopstick” arms, eliminating the need for landing legs and enabling rapid turnaround (booster can be immediately placed back on the launch stand).
– By offloading final velocity attenuation to the tower, the design increases payload capacity and launch cadence.
New SpaceX Super Heavy Booster V3 Design
The overall Super Heavy booster design for Block 3 incorporates broader upgrades beyond the grid fins, focusing on performance, reliability, and reusability.
Key technical details include:
– Slightly taller profile with an integrated hot-stage forward dome (inspired by N-1 and R-7 rocket truss designs), eliminating the need for a separate hot-stage ring installation and jettison. The liquid oxygen (LOX) tank features a revised chine setup with chines spaced farther apart for better glide-back lift.
– Switch to Raptor 3 engines (which have undergone ~300 tests and 16,000 seconds of firing time, addressing Raptor 2 issues). Center engines are clocked at 108/108/140 degrees for an asymmetrical layout to protect the flame diverter. Includes a redesigned fuel transfer tube (roughly the size of a Falcon 9 first stage) for channeling cryogenic fuel to the 33 Raptor engines, vacuum jacketing of feedlines, a new fuel feedline system for Raptor vacuum engines, and an improved propulsion avionics module. Propellant volume increased by 25%.
– Adopts a Falcon 9-style approach with two booster quick disconnects (one for LOX, one for LCH4) and removal of Raptor quick disconnects for easier refurbishment. Uses metallic tiles for heat protection instead of traditional shielding, plus a redesigned clamp and hold-down system for better alignment on the launch mount.
– A docking system for on-orbit refueling using a probe-and-drogue mechanism, with a second quick disconnect for fuel transfer. Reduced shielding on engines, except for thrust vector control actuators and gimbal mounts.
These changes enable:
– Performance boosts: Faster and more reliable flip maneuvers, simultaneous engine startups, and additional vehicle performance for longer missions. Payload capacity increases by ~40 tons to over 100 tons in reusable mode, with potential for 200 tons using nine engines (initially six: three Raptor Vacuum and three Raptor Sea Level, expandable to add three more Vacuum engines).
– Simplified refurbishment, improved glide-back lift, and on-orbit refueling capabilities, supporting rapid reuse and higher launch rates.
– Enables complex operations like Mars landings, with enhanced heat shield designs (latest-generation tiles with backup layers) suitable for Earth and Mars reentries.
Near-term Earth-based timelines include FAA approval for the next Starship flight test following the March 2025 eighth flight (with mitigations for engine issues), though the June anomaly may delay this. Expansion to Kennedy Space Center’s LC-39A and Cape Canaveral’s SLC-37 is targeted for completion in 2025 to boost flight rates. There will soon be four Starship launch towers.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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Actually–this is Jigsaw’s death machine for Elon
Great in depth review of Space X upgrades on V3… can’t wait until Felix (WAI) and Marcus House get this info, and do a deeper dive, with video, in the next week or so.
This is of course amazing work being done. But we need to be asking about the lunar landing system, which we’ve seen nothing about. This is a technology that has not been developed or proven since the 1970s, and that landing technology was with a vehicle that was a tiny fraction of the size and mass of this company’s massive rocket. The landing on the moon can end the mission in seconds. What is SpaceX doing to prove the moon landing is safe and reliable to a very high statistical probability?
Well, of course they won’t have any statistics until they’re actually flying it. But nobody has more experience with retropropulsive landing than SpaceX, and the fact that they managed to nail the tower landing really suggests that they’ll have no trouble landing on the Moon, where the gravity is much lower, and there’s no wind to deal with. The biggest question is actually landing on an unimproved surface, which calls for the lander to have actual landing legs.
All their development issues so far have been with things other than the actual landing.
If I had to fault SpaceX for anything, I’d say they lean too hard into being the opposite of Blue Origin.
Blue Origin has been so afraid to have failures that they’ve been trying to get everything right before actually testing hardware, and the result is that, despite starting before SpaceX, they only put their first payload into orbit this year.
SpaceX, by contrast, is so unafraid of failures that they’re maybe a little too aggressive about risk; I suspect they’d already be flying Starship with paying payloads if they’d been a tiny bit more risk adverse.
Under a different regulatory regime, their approach would probably have worked fine, but it gave the regulators too many excuses to keep shutting them down, which slowed them down.