Starship Flight 4 milestones make changes to Flight 5’s ship – NASASpaceFlight.com

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Following the highly successful milestones achieved by Booster 11 and Ship 29 on Flight 4 of SpaceX’s spaceship, engineers are already implementing the lessons learned leading up to the next flight, including large-scale changes to the Thermal Protection System (TPS). Although Elon Musk believes the next flight will take place in a month, Flight 5’s docking will require reapplication of stronger tiles prior to the mission.

Spaceship Flight 4 Overview

Expectations on launch day were high, as SpaceX hoped for a soft landing of Booster 11 and surviving the peak heat upon ship 29’s return. The road closure and tank farm cool-down went as planned, and the weather was nearly perfect for a launch.

Ship 29 and Booster 11 departed at 7:50 a.m. Central Time. Booster 11 immediately shut down Engine 15, which is in the outer ring, a departure from the past two flights, in which all 33 were running. However, this did not affect the booster’s ascent, with the booster completing the uphill journey without any other problems.

Then came the staging, with Ship 29 seamlessly fleeing from Booster 11 in a hot stage. Just seconds later, Booster 11 turned around and restarted the inner ten engines for the boost-back burn.

Unlike the last flight, all 13 engines ran for the entire duration of the fire before being shut down. SpaceX does this to return to the launch site for a catch, but in this case the target was 12 miles offshore in the Gulf of Mexico.

Shortly after the boost backburn, SpaceX debuted a new step in the launch: Teams jettisoned the hot staging atop Booster 11. This was probably done to reduce the mass at the top of the vehicle so that the vehicle could slide backwards more smoothly. To aid this process, SpaceX has installed a number of pneumatic pushers to push the ring away from the booster. It works similarly to the push system in the Falcon 9 intermediate stage to push the second stage away before igniting Merlin Vacuum.

Then a ship’s engine would shut down and a nominal Suborbital insertion, meaning ship 29 would follow the correct trajectory. Shortly afterwards, Booster 11 would fire up the inner 13 engines for an initial landing burn before switching to the inner three.

However, shortly after ignition, Engine 8 exploded in the inner ring of 10, but the booster continued to run. Subsequently, Booster 11 cemented itself in history as the first Super Heavy Booster in the Starship Program to complete a landing in the Gulf of Mexico. After the engine was shut down, Booster 11 overturned and was lost in the sea.

Looking back, ship 29, which was in the shore phase, had problems with the camera downlink, but these were resolved in time for return. After the shore phase, the ship oriented for reentry, which appeared to have a high angle of attack, like the Space Shuttle. This begins to slowly lose speed with the ship’s hull before tipping over and losing even more speed.

This was the beginning of the questions: will the heat shield hold up? Will the ship be able to maintain control during the return? Will Starlink provide an uninterrupted signal via reentry?

Slowly, like Ship 28, Ship 29 began to take on the glow of plasma as the ship entered the atmosphere at over 16,000 miles per hour. This happens because the air heats up so much due to friction that it creates another state of matter called plasma, which is made up of charged particles caused by the incredible energy around the vehicle.

As ship 29 moves through the atmosphere, the plasma continues to build up. This is the first time humanity has seen live plasma from remote cameras. Ship 29 would survive peak heating, achieving one of its most important objectives. However, during reentry, the lower control arm of the starboard forward hatch, as seen on the remote camera, had completely melted away, and the plasma ate a good chunk of it out as well.

However, despite the damage to the valve and other systems, Ship 29 would successfully survive the reentry. Then, even after all it had been through, Ship 29 performed a flip-and-burn maneuver, marking the first time a ship had done so since SN15, over three years ago. The maneuver was a success: the ship landed on the ocean and overturned intact.

Flight 4 problems and what this means for Flight 5

Looking ahead to Flight 5, SpaceX likely won’t need to make any significant changes to the booster as it successfully landed on target, as confirmed by SpaceX CEO Elon Musk. With this success, SpaceX will attempt a capture of Booster 12 during Flight 5. The engine failure during takeoff and the engine exploding during landing will be internally investigated for the causes.

Booster 12, which has been in Mega Bay 1 since January 23, 2024, awaits its turn for a static fire. Currently, there is no timetable for when this could be rolled out, as SpaceX has once again begun removing the hold-down clamps on the Orbital Launch Mount (OLM).

Ship 29 to ship 30 is a completely different matter. Although Ship 29 survived the re-entry and completed the flip and burn, many issues had to be addressed. First the plasma burned through the valve seals and almost cut off a flap. SpaceX will have to find a way to strengthen these areas for future flights. Second, although the heat shield allowed the ship to survive, there are still significant issues that need to be corrected.

Because of these problems, ship 30’s heat shield tiles and underlying blankets are already being removed and eventually replaced. The underlying blankets would be replaced with a new ablative material that may have been first introduced on Ship 29. As Elon Musk has stated, the tiles are being upgraded to a newer, much stronger design. Although ship 29 completed the flip-and-burn maneuver, it was several kilometers off target due to flap damage.

NSF’s Adrian Beil received a response from the Federal Aviation Administration (FAA) regarding a possible Flight 4 accident investigation: “The FAA has reviewed the operations of the SpaceX Starship Flight 4 mission. All flight events for both Starship and Super Heavy appear to have occurred within the scope of planned and authorized activities.” Without an accident investigation, SpaceX can proceed with Flight 5, but there’s no word on whether or not the current license can be used for a booster catch.

Overall, the preparations for the launch of Flight 5 will be interesting to watch as SpaceX gears up for a catch and aims for much better performance during the reentry.

Removal of 30 tiles along the way (Credit: Mary/BocaChicaGal for NSF)

Orbital launch pad B

The construction of the next Orbital Launch Pad (OLP) is gaining speed. SpaceX has the final two sections, along with the chopstick arms and carriage, on their way from Florida. Now that these parts are arriving, SpaceX is only missing a Ship Quick Disconnect Arm. There’s another one on Roberts Road, where SpaceX built OLP parts. However, this arm may need updating and will likely be built from scratch at Sanchez’s location.

As for when the tower could begin stacking, teams have made significant progress on the foundation: the tower’s pile cap has been poured and the crane parts needed to stack the tower are arriving. Unlike the last two towers, SpaceX will not use the Liebherr LR11350 crane, but a Demag CC 8800-1, which has more lifting capacity.

Orbital Launch Pad B Pile Cap Pour (Credit: Mary/BocaChicaGal for NSF)

A new interesting note about this tower is that the foundation will have hollow steel columns filled with concrete instead of concrete to which a steel shield must be added. The Orbital Launch Mount (OLM) will be located to the south, providing incredible views once a vehicle is stacked onto this new launch pad.

Main image: Ship 29 and Booster take off for Starship Flight 4. Credit: Mary/BocaChicaGal for NSF

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