SpaceX’s giant launch vehicle, the spacecraft, was fully assembled on the starbase launch pad. It is ready for its test flight, which will take place after two important tests. A one-time repeat of the take-off process and a static ignition of all 33 main stage engines.
On January 9, 2023, SpaceX assembled the two parts of the spacecraft, its future 120-meter-tall giant launch vehicle, on its launch pad! The upper stage, the transport vehicle, which bears the name Starship, was installed on top of the Super Heavy main stage, ie the booster needed to launch Starship.
This is the third time since August 2021 that the two parts of the launcher have been merged together, forming the Starship Launcher. The first two times they were placed on top of each other. This time they are assembled (or in the process of being assembled). The two parts of the launch vehicle were assembled using the “chopstick” arms of the giant crane, nicknamed Mechazilla, and built by SpaceX in two copies: one in Boca Chica, Texas, the other in Cape Canaveral, Florida.
Elon Musk expects the spacecraft’s maiden flight to take place within a few weeks, in March. Before that, two crucial main tests must be passed. A rehearsal of launch chronology with refilling (wet dress rehearsal in Nasa lingo) which consists of filling the tanks and completing all the phases before launch, but which will end before the end of the countdown. This is followed by a static ignition of the 33 Raptor engines on the main stage. This will be the first time all of the Super Heavy’s engines will be fired simultaneously. A previous test had been carried out with “only” 14 engines.
From Texas to the Hawaiian Islands
This first test flight should last about 90 minutes. The spacecraft will be placed in orbit about nine minutes after launch from the Super Heavy launch vehicle and fly to the Hawaiian archipelago, making a passage through space but without making a full orbit around Earth. If all goes according to plan, the Super Heavy’s main stage will be dry again, which will not be the case with the Starship. After an atmospheric re-entry, it was scheduled to sink after a controlled landing in the open sea off the coast of Hawaii. In early 2021, Elon Musk stated that “if he didn’t expect any particular problems with the launch of the Super Heavy and the spacecraft,” he on the other hand conceded that it will probably take “many iterations before SpaceX doesn’t perfect the reentry and landing maneuvers.” of the spaceship from orbit.
Fly a multi-engine launcher
To understand the difficulty of flying a multi-engine launch vehicle, it is necessary to know that the level of combustion from one engine to another is never the same and is very difficult to model, hence the importance of ground testing and the experience gained from Falcon 9 flights , whose main stage has nine engines, and the Falcon Heavy and its 3×9 engines – its main stage and consisting of three main stages of the Falcon 9.
The jet of each engine does not mean that these jets work together as if they were separate engines. These jets interact with each other and this can present numerous aerodynamic restrictions, particularly lateral ones, and therefore impede the machine’s climb. One of the jets can also shut down another engine’s jet! Another problem is the alignment of the motors. Of course it’s not the same to have three engines instead of just one! At such high flow rates, suction can occur in the skirt and create a vacuum effect.