At SpaceX Starbase, Booster 4 and Ship 20 continue processing operations for their test flight from a launch site that is now receiving its Mechazilla hardware.
The Quick Disconnect (QD) arm was installed on the Launch Tower, with the two “chopstick” arms now in the final stages of fabrication ahead of joining the QD arm on the Tower. This will create the combined Mechazilla system to be used for stacking and catching the vehicles.
Starbase Round-up:
While the focus remains on Booster 4 and Ship 20’s path to launch, Starbase continues to provide reminders of what is yet to come.
Extra welding robots were delivered to Starbase at the start of the week, ready to get involved with creating future Starships.
New nosecones and barrel sections being prepared inside Tent 3 were first seen by Mary (@bocachicagal), while another new design nosecone was also being fabricated.
Last week saw the rollout of a small Ground Support Equipment (GSE) Test Tank for a test later that week.
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Another road trip down Highway 4 in the coming days will be Booster 4, which is expected to depart the High Bay to return to the launch site for its own pre-launch campaign.
The vehicle has been undergoing – what Elon Musk described as – minor plumbing and wiring work since it first stood proudly on the Orbital Launch Mount before returning to the Production Site.
Signs that the return rollout is closing in include the re-installation of its RBoost Raptor engines, this time with the set expected to launch with Booster 4 during the milestone test later this year.
Additional pointers towards Booster 4’s upcoming rollout readiness revolved around the installation of its COPVs (Composite Overwrapped Pressure Vessels), which provide helium pressurization to spin-start the Raptor engines.
Those tanks will be fed from the Tank Farm, with the rolled-out Test Tank likely used to produce data on how the GSE tanks cope under cryogenic conditions.
The small GSE test tank, placed near the remains of Booster 3, followed a similar testing pattern to that seen with Starship test tanks, as its steel skin was covered in frost as liquid nitrogen filled the tank.
During the test, venting from its top valves ceased, a sign that pressurization was taking place. At this point, the tank would either survive or pop. With the tank remaining in one piece, the pressure was then released and the road opened, marking what can be presumed to be a successful test.
The readiness of the OLS (Orbital Launch Site) Tank Farm is just one part of the puzzle toward the historic test flight of Booster 4 and Ship 20. The Launch Tower and Mount will once again host the world’s tallest rocket, this time for pre-launch preparations as opposed to fit checks.
Although the Mount successfully held the rocket in place during the fit checks, it now needs to be ready to cope with a booster set to fire up 29 Raptors at T0.
It also needs to be the point of contact with the booster during propellant loading operations, as the Liquid Oxygen and Liquid Methane are supplied from the Tank Farm through the Mount and into the Booster’s tankage.
Preparations for that requirement took a step forward as the Propellant Loading Umbilical was installed on the Mount.
Other related elements, such as the propellant subcoolers, are also being worked on ahead of the milestone fuel loading event before launch.
While the Mount will provide the propellent loading requirements for the booster, the stacked Ship will be high off the ground. As such, it will require its own arm high up on the tower, providing propellants to the aft of the vehicle.
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Known as the Quick Disconnect (QD) Arm, this huge hardware was assembled at the launch site ahead of its installation onto the Tower.
Once in operation, it will also provide stability for the stack on the mount while being able to rotate quickly away from the vehicle ahead of launch, thus the term “Quick Disconnect.” This approach is used by a variety of vehicles and pads around the world.
Friday, Aug. 27 saw more work towards completing the OLS Tank Farm, with GSE-7 rolled out of the Mid Bay. Normally occupied by Starships ahead of nosecone installation, GSE-7 – which is effectively a “dumb Starship” – was built up inside the bay in preparation for its rollout to the launch site and eventual sleeving with a cryoshell.
GSE-7 made the trip to the launch site Tuesday, Aug. 30 with the small test tank moving in the opposite direction.
Meanwhile, Ship 20 continues to patiently sit out at the launch site, with the vast majority of work relating to replacing TPS (Thermal Protection System) tiles.
As seen before and after the short time it spent back at the Production Site, hundreds of tiles received markers, not unlike those seen during the Shuttle era with the Orbiter belly TPS.
However, now back at the launch site, the amount of markers is clearly being reduced as tile replacement efforts continue at pace.
Ship 20’s TPS being worked on, via Mary (@bocachcagal) for NSF
Meanwhile, the weekend finally saw the QD arm installed on the Launch Tower, with the huge structure initially moved into place on Saturday before being attached to the crane lines of the LR 11350 – nicknamed “Frankencrane” by SpaceX employees.
This set the stage for Sunday morning’s big lift, but not before an impressive display of formation flying from the Inspiration4 crew, who performed flybys of the Starbase facilities.
The crew are set to fly out of the Cape next month on a Crew Dragon but have been taking a keen interest in Starbase activities, with Dr. Sian “Leo” Proctor having already previously visited the launch site.
With its ever-changing skyline, the huge 145-meter tall Launch Tower finally received its QD arm via lift operations Sunday morning (Aug. 29), a process that appeared to go smoothly despite the challenge of gently installing it on the top half of the tower truss.
This arm is a key requirement of the full stack Starship, with fluid and electrical lines allowing the Ship to be fueled while atop Super Heavy.
However, it will also provide a role as a stabilizing arm for the booster during Starship stacking operations at the pad before continuing that role for the integrated stack.
As such, the QD arm is effectively one part of the “Mechazilla” system, as Elon has called it, given the stacking process will also include two “chopstick” arms that will remove the need for a crane – as seen during the fit check stacking operation – to lift the stages on to the launch mount.
Working through the night on Mechazilla – via Nic Ansuini (@NicAnsuini) for NSF
These fascinating arms will also be used to catch the vehicles as they return to the launch site, a role that gained them the most interest from the public since first being noted by Musk when he initially cited this approach as a way of deleting the landing legs from the booster.
Fabrication of the Mechazilla chopsticks is near completion, again – as with the QD arm – a process that is taking place at the launch site.
One central element to the catch arms – via Mary (@bocachicgal) for NSF
Their installation onto the Launch Tower could take place in September, allowing for checkout operations ahead of being put into operation.
Booster 4 and Ship 20 won’t be returning to the launch site at the conclusion of their test, but Mechazilla may be used to stack the vehicle ahead of the flight.
On when the first catch attempt could occur, Musk confirmed that the following mission is the current hope.
That is likely to be a decision based on how Booster 4 performs during its return for a soft splashdown off the coast of Texas, an objective not unlike the early Falcon 9 landings to prove the accuracy of the approach and touchdown.
Should Booster 4 prove the controllability of reaching a pinpoint landing on the ocean, it’s likely Musk will push on with the Return To Launch Site (RTLS) attempt, with the booster conducting the landing burn near the tower before being caught and gently lowered back on to the mount by the chopstick arms.
With hardware preparations proceeding at pace, the launch date is most likely to be a situation of awaiting clearance and final approval. There is currently no timeline for such a process, including the final green light which will come from the FAA (Federal Aviation Administration).
Photos and videos provided by Mary (@bocachicagal) and Nic Ansuini (@nicansuini). Additional information and article assistance provided by the NSF (L2 Level) Discord.
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