SpaceX CEO Elon Musk gave an update yesterday that the Starship rocket Super Heavy Booster 4 prototype is going under installation of the Raptor engines. But it was not confirmed that how many rocket boosters were being installed on this Super Heavy prototype.
Now, earlier this morning, SpaceX officially confirmed that 29 Raptor engines have been installed on the Booster 4 prototype (previously called BN4). The space exploration company also shared a couple of pictures of the rocket booster’s forward fins and under the aft section where the installed engines can be seen.
This is the same Super Heavy Booster 4 prototype, of which, Elon Musk shared an image of the massive and complex fuel feed system for 29 Raptor engines last week.
Looking at the picture closely, I have found that SpaceX has installed 29 Raptors engines in a 20-8-1 configuration on this booster prototype. This config means that there are 20 fixed engines installed on the outer ring, 8 gimbal engines on the inner ring, and a single gimbal in the center.
Since there was already a road closure notice in place the Cameron County from 9:30 a.m. to 3:00 p.m. today. SpaceX has already moved the Super Heavy Booster 4 out of the High Bay to the launch pad at Boca Chica, Texas launch site around 11:30 a.m.
Elon Musk has just shared a short video of this Super Heavey Booster being moved to the orbital launch mount at the launch site.
In response to a question about the grid fins on the Booster 4 not being evenly spaced as they are on the Falcon 9 rockets, in response, Musk shed light on the function of the grid fins:
Pitch control requires more force than yaw & much more force than roll. Also, grid fins closer to or in the wake of the booster are less effective.
However, pretty good aero control can technically be achieved with only 2 grid fins, with some effect on accuracy.Elon Musk via Twitter.
Musk has just shared a few more stunning aerial photos of the Super Heavy Booster 4 from the orbital launch mount at Boca Chica, TX.
Moving this massive 72 meters tall stainless steel structure with 29 giant Raptor engines is a historical event in its own right. Landing it back after the first stage separation will be even more historic and intensely interesting to watch. But SpaceX has not yet confirmed the Starship orbital flight test date.