SpaceX
SpaceX is targeting June 5 for the next flight of its massive Starship rocket, the company said Friday.
The much-anticipated test flight – the fourth in a program aimed at bringing the Starship into operational readiness and making progress towards its eventual reuse – will seek to demonstrate the ability of the Super Heavy first stage to perform a soft landing in the Gulf of Mexico and for the Starship’s Upper Stage to made a controlled reentry through Earth’s atmosphere before falling into the Indian Ocean.
This mission will carry no payload as SpaceX seeks additional flight data on the performance of the complex Starship vehicle. It is both the largest and most powerful rocket ever built and the first launch system ever to be fully and rapidly reusable.
As part of its flight date announcement, SpaceX provided some information about its findings from its latest flight test, Flight 3, which launched on March 14, 2024.
Dissecting flight 3
During this flight, SpaceX also attempted a soft landing of the Super Heavy first stage. After its separation from the starship’s upper stage as intended, 13 of the Raptor Super Heavy’s 33 engines successfully re-ignited to perform controlled flight through the lower atmosphere. However, six of these engines shut down prematurely during this boostback burn. Later in the descent, as the rocket approached sea level, the rocket was to use the same 13 engines to burn up on the final landing.
“The six engines that shut down prematurely during the afterburner were prevented from attempting to start on landing, so seven engines were commanded to fire and two successfully achieved main stage ignition,” the company said in its flight summary. “The booster had lower than expected landing thrust when contact was lost approximately 462 meters above the Gulf of Mexico and less than seven minutes into the mission.”
The cause of this failure was traced to a clogged filter where liquid oxygen flows into the Raptor engines. Notably, a similar problem occurred during Starship’s second test flight in November 2023. SpaceX says it implemented “hardware changes” to resolve the stalling issue for the third test flight. Now the company has said, “Super heavy boosters for Flight 4 and beyond will get additional hardware in the oxygen tanks to further improve fuel filtration capabilities.” It will be interesting to see if the company’s engineers successfully tackle this problem.
As for the upper stage of the starship, the vehicle began to lose its ability to control its position during the coast phase in space. This was found to be caused by clogged valves used to control the reaction in the upper stage. A company update notes that “SpaceX has since added additional spin control thrusters on upcoming starships.” But it’s not clear that they will be available for Flight 4. The fact that SpaceX No an attempt to re-ignite the Raptor engines in flight on the starship’s upper stage suggests that these new pitch-control thrusters are not yet in place.
Ultimately, this lack of attitude control during Flight 3 resulted in a non-nominal reentry into Earth’s atmosphere. SpaceX was able to maintain contact with the vehicle up to an altitude of 40 miles (65 km) before losing telemetry due to excessive heating.
Back to basics
During Flight 3, SpaceX achieved some important milestones, including the opening of the starship’s cargo bay door in space and a small fuel transfer demonstration. However, due to the loss of attitude control, the planned re-ignition test of the Raptor rocket engine was not carried out. This is an important test because igniting the Raptor is necessary to perform a controlled reentry—essentially making sure the starship returns to a remote part of the ocean, not land.
For the next flight, SpaceX will focus on solving the technical problems observed in Flight 3: filter clogging observed during the Super Heavy boostback and landing burns, controlling the position of the starship during its coastal phase, and managing the return of this vehicle from orbital velocity.
Once those issues are resolved, the company can move on to more advanced tests, including landing the Super Heavy shuttle back to the South Texas launch site, deploying the Starlink satellites, and additional propellant transfer tests necessary for NASA’s Artemis program to land humans on board. Moon.