SpaceX is busy preparing for the orbital launch of its next-generation Starship rocket, but the company’s rocket factory in South Texas is also working around the clock to prepare several other sets of ships and boosters for testing in flight that will follow.
That was more evident than usual on Nov. 8, when SpaceX took steps to prepare its two finished ships for further phases of testing. SpaceX kicked off the eventful day by removing Starship S25 – a newer prototype that arrived at the launch site just three weeks prior – a stand dedicated to proof test ships. Three hours later, after spending three of the last four weeks sitting on top of Super Heavy Booster 7, Starship S24 was “unstacked” (raised from the B7 and lowered onto a ground support) in the early afternoon. .
Booster 7, Ship 24 and Ship 25 have all been occupied since mid-October. SpaceX stacked Booster 7 and Ship 24 for the first time on October 11, then attempted to test the fully stacked rocket on October 13. According to some accounts, although almost nothing was visible to the public, the first full stack test may have gone wrong, potentially even in danger pad technicians who approached the rocket to troubleshoot. On October 16, SpaceX completely unstacked Ship 24 and CEO Elon Musk noted that the company was “proceeding very carefully” to avoid an explosion that could set back “the vessel’s progress by approximately 6 months”.
But if there was a major problem on Oct. 13, SpaceX didn’t show it, and Ship 24 was reinstalled on Booster 7 on Oct. 20 without any obvious maintenance or repairs. SpaceX then launched a series of unusual tests on October 24, during which it filled only liquid oxygen (LOx) Where the liquid methane tanks (LCH4) of the Super Heavy B7, the Ship 24 or both vehicles at the same time. A rare NASA briefing October 31 later called them “single-species prop[ellant]“tests – a kind of extra-cautious test that had never been seen before at Starbase. A few days earlier, a member of NASA’s Aerospace Safety Advisory Board (ASAP) noted that a accidental explosion which damaged Booster 7 in July had caused SpaceX increase [the rigor of its] systems engineering and risk management,” explaining the sudden influx of unusually conservative testing.
By the time Ship 24 was unstacked from Booster 7 on Nov. 8, SpaceX had completed seven single-species tests, four of which involved loading LOx or LCH4 in both stages and three of which tested only Super Heavy. The reservoirs of Booster 7 and Ship 24 were fully filled and LCH4 and LOx were never loaded simultaneously on both stages.
NASA’s Oct. 31 briefing reported that SpaceX intended to unstack Ship 24 before conducting additional static fire tests with Booster 7. While B7 conducted static fires of 1, 3, and 7 engines in August and September, these tests were far from the full 33. -engine static fire needed to properly qualify the most powerful rocket in history. According to the editor of NASASpaceflight.com Chris BerginSpaceX’s next goal is to fire about half of the Raptors from Super Heavy B7.
Strangely, although Ship 24 is believed to have completed all of the autonomous testing necessary to clear it to fly, SpaceX installed the vehicle on a stand used for Starship static fire tests on 9 November, implying that more standalone testing may be required. For now, this shouldn’t be a problem as long as SpaceX completes all additional Starship testing around the same time as the next Booster 7 static firing campaign, but it could delay full launch preparation if that takes longer.
Finally, after Ship 25 was removed from SpaceX’s other spacecraft testbed on Nov. 8, it was returned to the Starship factory at Starbase. Ship 25 first arrived at the launch site on October 19 and has since completed four visible tests. On October 28, Vessel 25 survived a pneumatic proof test which showed her tanks to be leak-free and able to withstand flight pressures (approximately 6-8.5 bar or 90-125 psi). Three cryogenic tests followed on November 1, 2 and 7. The first cryoproof was probably just that – a test that pressurized the ship’s 25 tanks and filled with cryogenic liquid nitrogen (LN2) or a combination of liquid oxygen and LN2.
The next two tests likely took advantage of the custom test rig, which was semi-permanently outfitted with a set of hydraulic cylinders that allow SpaceX to simulate thrust from six Raptor engines while Starship structures are cooled. at cryogenic temperatures and loaded with approximately 1000 tons (~2.2M lb) of cryogenic fluids. If a spacecraft can survive these stresses on the ground, the assumption is that it will likely survive similar stresses in flight.
Assuming the initial proof tests of Ship 25 were successful, which they appear to have been, SpaceX has returned the prototype to its Starbase factory to install six Raptor engines and a series of shields and firewalls that will protect those engines. one another. Once fully outfitted, Ship 25 will return to the launch site for static firing tests and take the place of Ship 24 on Suborbital Block B. Ship 24 took approximately two months to transition from its last cryoproof to its first static fire. But his tests resulted in a relatively difficult startso that ship 25 is ready sooner.
SpaceX could begin the next phases of testing Booster 7 and Ship 24 as soon as November 10 or November 13.