SpaceX published the analysis of the third Starship flight, which took place on March 14, 2024. Along with this, it announced that the fourth flight will take place NET June 5. This means that the launch will be no earlier than June 5th, but not necessarily on that day. The date, as well as any technical delays, it will also depend on the arrival of launch permitswhich have not yet been released by the FAA.
The third Starship flight was a big step forward for SpaceX compared to the previous one, but as emerged from the analysis there are still many phases and operations to be perfected. Recently, both Musk and Lisa Watson-Morgan, manager of NASA’s human landing system, said that the goals of the fourth flight will be less ambitious than expected.
The main purpose will overcome the heat peak experienced during the Starship’s re-entry into the atmosphere and complete the Super Heavy’s descent by ditching.
On June 5th, or one of the following days, we will follow the launch of Starship together on the Astrospace YouTube channel:
Analysis of the third flight – The Super Heavy
SpaceX said that after separating from Starship, 13 of the Super Heavy’s engines fired simultaneously and then six of those shut down prematurely, but without causing damage.
The booster then continued to descend until the moment it was supposed to re-ignite the same 13 engines as before. However, the six engines mentioned above, the ones that were shut down prematurely, did not restart, leaving the final maneuver to the remaining seven, of which only two started correctly. SpaceX confirmed that contacts were lost 462 meters above the surface of the Atlantic Ocean, as they had already announced after the flight.
The most likely cause of these late-stage engine ignition problems appears to be blockage of the filters where liquid oxygen is supplied to the engines, and this led to a loss of pressure in the Raptor’s oxygen turbopumps.
SpaceX stated that hardware changes had already been made before the third flight to resolve this problem, but not enough. The Super Heavy which will be used for the fourth flight, will have additional modifications to improve propellant filtration.
The analysis of the third flight – The Ship
SpaceX confirmed that the test of transferring propellant, specifically liquid oxygen from a main tank to a header tank, was successful. It was also confirmed that the Ship lost control of its attitude a few minutes after separating from the Super Heavy, and this automatically triggered a command to block the Raptor engine’s ignition test.
The main cause of this loss of attitude appears to be the clogging of some valves in the roll control system. SpaceX stated that in the next Ships thrusters have been added and the hardware (valves) have been updated and improved.
SpaceX finally confirmed that the flight permit for the fourth launch has not yet arrived from the FAA, but that it may be issued even before the formal closure of the investigation into flight number 3. This is because no flight termination system has been activated ( the FTS) and no debris from the Super Heavy or the Ship was detected outside the previously predicted areas. The investigation into SpaceX’s flights is being conducted by the FAA, with participation from NASA and the National Transportation and Safety Board (NTSB).
SpaceX’s statement on the analysis of the third flight can be found here.
The fourth flight
The launch window for the fourth flight will open at 07 AM local time, i.e. 2pm Italian time. The trajectory will be similar to that of the third launch, with a landing of Starship in the Indian Ocean. The confirmed objective is the return of the Booster and that of the Ship.
This time however, with the Ship it seems that they will want to perform a landing burn, i.e. ignition of the Ship’s engines immediately before touching the water. This maneuver is indicated in the official launch timeline, but has not yet been confirmed by SpaceX. In fact, performing a landing burn would mean righting the Ship and not performing a side ditching, as planned for the third flight.
One of the confirmed updates for the fourth flight will be the expulsion of the upper ring of the Super Heavy, used to protect it during the hot staging phase. This ring will be ejected shortly after the two stages separate, to decrease the mass of the booster during descent.
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