CEO Elon Musk says that SpaceX is set to attempt one final Raptor engine static fire test before putting Starship through its high-altitude launch debut later this week.
Liable to begin as soon as November 30th per public road closure notices, Musk says that Starship serial number 8’s (SN8) launch debut – both Starship’s first fully-assembled flight test and first high-altitude launch attempt – is now scheduled no earlier than (NET) 8 am to 5 pm CST (UTC-6) on Wednesday, December 2nd.
November 30th will instead host what is believed to be a unique kind of static fire test for Starship SN8, hopefully proving that the rocket has a decent shot at surviving its risky launch debut.
As previously discussed on Teslarati, SpaceX’s Starship development strategy means that SN8’s survival is far less important than it may seem.
“On November 25th, Starship SN9 (featuring “small improvements”) was stacked to its full 50-meter (~165 ft) height. If SN8 is destroyed during testing, SN9 will likely be ready to roll to the launch site almost as soon as the dust settles.
Meanwhile, Starship SN10 is likely just 7-10 days away from a similar nosecone stacking milestone, and Starship SN11’s tank section is just one stack away from completion, likely putting it less than two weeks behind SN10. In other words, insofar as speed is a priority and each prototype is anywhere close to as cheap as Starship’s majority-steel bill of materials might suggest, SpaceX is building Starships so quickly that it almost doesn’t make sense to spend more than a few weeks working through bugs on any single suborbital ship.”
Teslarati.com — November 25th, 2020
In fact, delaying SN8’s launch to try to refine the rocket in situ and better ensure success could actually be to the detriment of successive prototypes and the Starship program in general. If, for example, a fundamental design flaw is revealed in Starship SN8 only after the prototype’s first test flight, SpaceX could be forced to scrap a huge amount of work done on as many as six, seven, eight, or even more subsequent prototypes. In that since, while it may seem like caution maximizes the value any single Starship prototype can provide SpaceX, that’s only true as long as the Starship design is mature enough that new fundamental flaws are unlikely to arise.
Given how young SpaceX’s agile Starship development program is, it would make very little sense to hinge months of work and more than half a dozen rocket prototypes on the quality and success of a less mature prototype unless all the vehicles in question are more or less identical final products. SN8 through SN15+ are certainly not final products in the sense that Starship is meant to be the largest reusable orbital spacecraft ever built.
As such, the Starship program is probably better off if SpaceX pushes vehicles to failure as quickly as reasonably possible. Having now spent more than two months at the launch pad while no less than three full-scale prototypes rapidly approach a similar level of completion, Starship SN8’s test flow is likely an overcorrection from a haphazardly rushed schedule to extreme caution.
Along those lines, SpaceX is now hopefully set on launching Starship SN8 within the near future. First, though, the company apparently plans to attempt another Raptor engine static fire test on Monday, November 30th. Scheduled between 7 am and 9 pm CST, the test has been described as a “handoff” static fire, referring to the process of switching each Raptor engine’s propellant feed from Starship’s main tank to much smaller ‘header’ tanks reserved for landings.
What exactly that handoff refers to is unclear. It could mean that SN8 will switch from main tanks to header tanks during a Raptor static fire test, though it’s unclear why that capability would be necessary unless Starship’s current header tank design is too small. “Handoff” could also refer to the process of switching between main and header tanks between Raptor operations – far more likely. In other words, Starship SN8’s Monday testing might involve two back-to-back static fires, performed with no human intervention. If successful, such a handoff static fire would simultaneously test Starship’s ability switch propellant sources and perform multiple Raptor engine ignitions – both necessary for a launch and landing.
Musk himself believes that Starship SN8 has a ~33% chance of successfully launching, reaching apogee, stably ‘skydiving’ ~14 km (~9 mi) back to Earth, reigniting Raptor engines, and landing in one piece. It’s unclear what will happen in the seemingly unlikely event that SN8 survives, but Starship SN9 is practically nipping at the relatively ancient prototype’s heels.