Starship Flight 3 Fully Stacked for WDR testing

by Ryan Weber

SpaceX is making good progress on Flight 3 readiness with a full stack on the pad and road closures coming up for a possible Wet Dress Rehearsal (WDR) for Booster 10 and Ship 28. SpaceX continues to work on future flight vehicles, on the path towards achieving operational status with Starship.

Flight 3 Full Stack

SpaceX rolled out Booster 10 and Ship 28 for what is hoped to be the final time before launch.

Booster 10 was rolled out on Feb. 8 during the day and stacked later that night. Ship 28 was then rolled out on Feb. 10 in the middle of the night and stacked the early morning of Feb. 11.

Even with the delay during the day, between Booster 10 entering the launch site and Ship 28 settling down, SpaceX managed to complete the entire operation in under 56 hours. This rapid pace will be required in the coming years as SpaceX attempts to ramp up its flight cadence for Starship.

While Booster 10 was in the Mega Bay, SpaceX appears to have made some changes to the bottom of the Liquid Oxygen (LOX) tank.

It is now observed there are two sets of new weld lines that appear to be for a set of slosh baffles at the bottom of the tank. Slosh baffles are used to help prevent the liquid propellant from sloshing around the tank.

These additions could be in response to the Booster 9 failure during flip and boost back burn, although SpaceX hasn’t officially said what the cause of the failure was.

Booster 10 Rollout (Credit: Mary (@bocachicagal) For NSF)

For this week, there are currently three closures, running from Feb. 12 through 14. All three days run from 8:00 am to 8:00 pm CST.

During these windows, Booster 10 and Ship 28 are set to perform a partial Wet Dress Rehearsal (WDR) and then a full WDR probably a day or so later. For a partial, SpaceX is expected to only load the booster and ship to possibly around half full or less, testing all of the new systems and changes to the Orbital Launch Pad (OLP).

A WDR is where SpaceX and other launch companies test a rocket and its countdown. During a WDR, the vehicle is fully loaded with propellants, in the case of SpaceX’s Starship, it is LOX and Liquid Methane (LCH4).
While it is loaded, the full launch countdown is run through right up to engine ignition. However, the engines aren’t ignited, and after the countdown and other testing is completed, the vehicle is detanked.

SpaceX has completed a WDR for the past two flights, Jan. 23, 2023 for Booster 7 and Ship 24, then Oct. 24, 2023 for Booster 9 and Ship 25. In this case, teams will be testing several changes to the tank farm, including the addition of four more subcoolers on the LOX side plus two pumps and one more subcooler and pump on the LCH4 side. Along with that, teams removed the old water shell tank and the repurposed CH4 tank that became a water tank. 

With all of these changes, SpaceX should be able to have a shorter countdown for propellant load, where instead of 97 mins to load all of the LOX and LCH4, it could be reduced to around 50 mins.

After completing a partial and full WDR, the plans for this stack are unknown. Teams have yet to install the S28 and SpaceX decals on Ship 28. While it was on the engine install stand, teams may have swapped some Raptors.

During the lift onto Booster 10, however, no stiffener rings were installed on the Raptor vacuum engines. The stiffeners are required in order to static fire the Raptor Vacuum engines on the ground.

However, that doesn’t fully rule out a static fire since teams can reinstall the rings if needed, and the sea-level raptors can still be static-fired.

Although in the early morning of Feb. 12th SpaceX destacked Ship 28 from Booster 10 after crews had a lift up looking at one of the ship clamps.

After destack, teams spent the day working on the clamps on the hot stage ring and on the ship side. This destack could be because during stack the clamps might have been damaged and require repair.

By Tuesday morning, Ship 28 was restacked, allowing SpaceX to return to the configuration that will allow for the WDR test campaign.

Launch Pad

The OLP has been receiving some finishing touches as SpaceX continued to prep the pad for Flight 3. All of the scaffolding, plus an alignment rig used to align the hold-down arms and clamps, was removed shortly before Booster 10 rolled to the pad.

Cleaned up OLM ahead of Booster 10 Rollout (Credit: Mary (@bocachicagal) For NSF)

Teams have also continued to add the final pieces of shielding to the tower’s concrete base, which will help prevent erosion on the concrete. Along with that, there have been several small things SpaceX continues to finish up as Flight 3 gets stacked for the first time. 

Work is also taking place on the new blast wall that protects the LOX tank farm components and the communication bunker at the Orbital Tank Farm (OTF), as well as painting the new stiffener bars that were placed on the exposed cryo shells.

FAA Update

NSF received a statement from the Federal Aviation Administration (FAA) on the current status for the launch modification for Flight 3 of Starship.

The FAA said that the mishap investigation for OFT-2 is still open, pending more information from SpaceX. The license modification requires all needed information to be submitted and reviewed, and the investigation needs to be closed before Starship returns to flight.

SpaceX and FAA are working together to resolve the investigation, and Starship returned to flight. 

Vehicle Update

After Flight 3, Booster 11 and Ship 29 are slated for Flight 4. Currently, based on a SpaceX post on X last week, Booster 11 may have all of its engines installed and could be very close to being ready for a static fire.

Ship 29 should also be getting its engines – if it already doesn’t have them all – as Raptors have been seen going into Mega Bay 2. If Flight 3 goes well and the pad is in good shape, Booster 11 and Ship 29 could roll out relatively shortly after launch.

Booster 12 (Left) and Booster 11 (Right) in the Mega Bay (Credit: Sean Doherty for NSF)

For Flight 5, there is Booster 12 and Ship 30. Booster 12 is currently sitting on the center work stand in the Mega Bay, getting fitted with engines ahead of static fire testing. Ship 30 is in the High Bay, slowly getting ready to take the second ship work stand recently installed in Mega Bay 2.

Flight 6 has gotten a big update in the past few weeks, as Booster 13 is fully stacked and will be completed ahead of cryo-proof for the next few months. Ship 31 is having its crane lift points tiled over and general heat shield work ahead of cryo testing.

With a full stack for Flight 3 at the pad, a possible WDR on the horizon, and an update from the FAA, Flight 3 is getting closer and closer to launch.

Lead photo via Mary (@bocachicagal) for NSF.

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