After a few false starts and some small delays, SpaceX’s 11th starship prototype (SN11) underwent two of the three main tests between it and takeoff.
SpaceX rolled the Starship SN11 from the factory onto the launch pad on March 8, just five days after the Starship SN10 briefly became the first prototype of its kind to land entirely. One or two problems with Raptor’s final landing burn caused the SN11 to land faster than expected and eventually led to the rocket’s explosive death 15 minutes later. Still, the test flight was an almost unequivocal success and apparently left SpaceX with more than enough confidence to speed up preparations for the next flight test.
The next day, SpaceX hoped to start cryogenic testing, but Starship SN11 demanded a little more attention than expected and unknown bugs ultimately meant that only a pressure test at room temperature could be completed by the end of the test window. These problems appeared to persist until the end of March 10, preventing any kind of proof test attempt.
On March 11, the SN11 starship was able to make its first real attempt at a cryogenic test and was charged with liquid nitrogen (LN2), a cryogenic fluid with a density and temperature similar to the starship’s liquid oxygen and methane propellant, but without the risk of a catastrophic fire or explosion. Over the course of about three hours, SpaceX did not appear to fully load the SN11 with LN2, a possible sign of a technical bug that could easily be an intentional part of the test design.
Strangely, parts of the night tests were different from previous cryogenic tests and there is a small chance that the activity was actually an attempted static fire rubbed well before ignition, although it is impossible to say without official confirmation.
Otherwise, the most notable part of the cryogenic test was a test of the attitude control system (ACS) of the starship SN11, which involved firing each of the various cold nitrogen propellants at least 5-10 times to a total of several dozen explosions. The current generation of Starships primarily uses these thrusters to increase their flaps and perform flip maneuvers during suborbital launch and landing attempts, while early orbital class prototypes can use the same propulsion system to control their attitude in the vacuum of space. .
If the previous night’s cryogenic-proof test was successful and gave SpaceX the data it needs to give the SN11 a good clean bill of health, the starship could potentially try its first static Raptor engine fire on Friday , March 12. Historically, SpaceX has never statically fired a prototype starship less than 12 days after its arrival at the launch site, meaning that a static fire tomorrow would break the previous record by a factor of three. As such, the SN11 is more likely to need a day or two and is ready for a static fire attempt as early as Monday, March 15.
Anyway, Starship SN11 is undeniably on a faster track than any of its three-engine predecessors and a clean static fire on Friday or Monday would leave a launch next week – SpaceX’s current goal – well within reach .