SpaceX assembles Ship 25 and Booster 9, and gets ready to fly

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SpaceX has sent Ship 25 to the launch site and placed it on top of Super Heavy Booster 9, returning the fully stacked Starship rocket to Starbase since April 20th.

Several significant additions were made to the Ship 25 prior to this assembly and should make the vehicle ready to fly. SpaceX is now looking forward to the last few days of preparations before the Starship’s second test flight, pending regulatory approval.

The ship receives 25 upgrades, and is stacked to Booster 9

Ship 25 has remained at Starbase’s Rocket Garden for the past month, after it was returned from the launch site on Aug. 5.

Since then, not only has the car undergone final preparations for flight with the addition of TPS tiles to the front and new livery, but it has also undergone a number of other changes as well.

Its long stay and slow installation of TPS tiles suggests that there is more work to be done than originally thought. Close-ups of the leeward side of the ship show that SpaceX has been pretty busy introducing a series of last-minute changes to its latest Starship prototype.

A view of the ship’s common dome section 25 showing the new set of tolls added to the vehicle prior to the voyage. (Credit: Jack Baer for NSF)

One of these upgrades includes the addition of a Vehicle Trip Termination System (FTS) surcharge. During the Starship’s maiden flight, the automated FTS system was triggered in both stages after the missile lost control and drifted off course.

However, as CEO Elon Musk stated a few days after the launch, the accusations were not strong enough to unravel each stage as they were supposed to. This new upgrade was already implemented on Booster 9 a few months ago, and it is hoped that by adding additional explosive charges on each vehicle, these charges will actually disintegrate if this system needs to be activated on the fly.

The teams also added what appears to be a new set of hatches or air vents in the aft section of the 25 directly above the vehicle’s engine shield. The location of these air vents is similar to the Booster 9 ventilation system at the rear end of the vehicle. These vents on the Booster 9 are believed to be part of the carbon dioxide (CO2) purge system that prevents fires from starting and spreading throughout the engine section of the vehicle.

This is another problem that may have been encountered on Starship’s maiden voyage, as fires were clearly seen between the booster engines. This fire may have been caused in part by the loss of control of the vehicle less than two minutes into the flight.

View of the stern section 25 showing the new row of hatches above the engine shields that should provide ventilation to these cavities. The reinforced welds and the new set of tubes can also be seen in this photo (Credit: Jack Beyer for NSF)

With these new nozzles now also on Ship 25, SpaceX likely wants to ensure that no control of the craft is lost during flight due to any engine fire and that all critical instrumentation in the engine section remains as intact as possible.

In this engine section, a new set of tubes were added to the port and starboard leeward side of the ship. These look similar to the engine coolant tubes already in the car and are where gaseous oxygen is vented outside so that it does not collect inside the engine section.

These engine coolant tubes have an extension on the booster side where they connect to allow this oxygen to be vented much further down the rocket than anything else. However, the new tube set recently added to Ship 25 will not experience a similar stretch on the booster side.
At the moment it is not clear what they might be for, but the absence of these extensions could mean that whatever is vented through these tubes may not be vented during first-stage flight as gaseous oxygen but only while the engines are ignited.

The aft end of the 25 also saw reinforcements added to the seams between the rings at and below the umbilical plate. This is not a new upgrade, it is an upgrade that has already been implemented on Ship 24 for its own flight and SpaceX seems to have fallen behind on Ship 25.

It is believed that it had to be fitted to the Ship 24 due to structural tests which revealed problems with this part of the vehicle. However, these changes have now been implemented on Ship 25, and it should be ready for its next voyage.

The ship’s stacking of 25 on September 5 gave observers the perfect opportunity to look down on the engine section of the ship. Each of the ship’s 25 engines can now be seen fully protected, and its turbine machinery well protected from possible damage.

While Booster 9 will feature the first of the new electric propulsion control (TVC) system, Ship 25 will still have the older hydraulically actuated TVC system, which involves using a hydraulic power unit (HPU) to drive that system.

This HPU is located inside the motor section and is surrounded by the same heavy armor that protects the motors. This should avoid issues encountered during the Starship’s maiden voyage, where Booster 7’s HPUs were seen to catch fire during the ascent portion.

The stacking Tuesday also marked the first time a booster with the new hot grading ring has carried a ship on top of it. The delicate lift of Ship 25 lasted over an hour and ended with the vehicle being placed on Booster 9 at approximately 2:20 PM CST. This was made noticeable by the sudden jolting of the entire rocket as the ship’s weight rested on the booster.

With this extra ring on the booster adding an additional six feet (1.8 meters) to the overall height of the rocket, SpaceX’s Starship broke its own record for the world’s tallest rocket, previously held by Ship 24 and Booster 7. Stack.

The company’s CEO, Elon Musk, stated on Twitter that the vehicles are ready for launch and that only FAA approval still awaits them. This may mean that SpaceX will not perform major rocket tests until launch. Depending on how long it takes for the FAA to get approval, the company may decide to run some tests to gather additional data before the flight.

While this full stack is the first since April 20th, it likely won’t be the last before the next launch. The ship is expected to be dismantled 25 days before launch in order to prepare its flight termination system for flight.

This will involve teams boarding each of the vehicle’s FTS control boxes and removing the physical safety pins that prevent accidental release of explosives.

This is expected to happen shortly after SpaceX received approval from the Federal Aviation Administration (FAA) for this second flight of the Starship, in a similar way to what happened on the first flight.

(TOP PHOTO: Ship 25 and Poster 9 at sunrise on Sept. 6. Image credit: Jack Beyer for NSF)

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