Crucially, though Elon Musks levelheaded realism (or pessimism) has often appeared to ignore the real chances of success, the SpaceX CEO is substantially more confident on Starships 3rd launch attempt than he was on the first flight 2 months back. Back when Starship identification number 8 (SN8) was preparing to try the programs first high-altitude launch, Musk pegged the possibility of a successful launch, freefall, and landing at ~ 33%.
As it turned out, he wasnt incorrect, however Starship SN8 eventually made far closer to an overall success than nearly anyone– inside SpaceX or not– anticipated it to get on the very first shot. Less than two months later on, Starship SN9 suffered a similar last-second landing failure more than 6 minutes into the flight, though the source of both failures were unique.
After two Starship prototypes aced their high-altitude launch debuts only to suffer last-second landing failures for unique reasons, SpaceX is tailoring up for a third launch as early as this week.
Success on landing probability is ~ 60% this time– Elon Musk (@elonmusk) February 14, 2021
Presently installed on one of 2 suborbital stands at SpaceXs South Texas launch pad, Starship SN10 will be the very first high-altitude model to try that three-engine flip burn and on-the-fly downselect. Musk states his confidence that SN10 will effectively land is now 60%, a nearly twofold enhancement over SN8. Starship SN10 might potentially fly as early as this week, though the model still needs to finish a small three-engine static fire test and the launch has yet to receive FAA approval.
That obvious fine-tune: reignite all three of Starships readily available landing engines, not just 2.”
In the meantime, Starship SN11 is efficiently total and Starships SN15 through SN18 are being assembled to support a ruthless flight test project as SpaceX works towards orbital flights.
Simply put, both flight tests served their nominal purpose, uncovering two failure modes that would have eventually reared their heads one way or another. With SN8, Starship was not able to preserve sufficient pressure in its secondary landing fuel tank to supply two Raptor engines with adequate fuel for a landing burn. Starship SN9 stopped working a few seconds before SN8 when among the 2 Raptor engines required for a flip and landing burn never ever sparked, causing the rocket to smash into the ground at an angle relative to SN8s tail-down impact.
Excellent analysis. Were working on lowering min throttle of Raptor, so that there is engine redundancy throughout the landing burn.– Elon Musk (@elonmusk) February 13, 2021
With SN8, Starship was not able to keep enough pressure in its secondary landing fuel tank to supply two Raptor engines with sufficient fuel for a landing burn. Starship SN9 stopped working a couple of seconds prior to SN8 when one of the 2 Raptor engines required for a flip and landing burn never fired up, triggering the rocket to smash into the ground at an angle relative to SN8s tail-down effect.
That apparent tweak: reignite all three of Starships offered landing engines, not simply two.”
By firing up not simply two– but all three– Raptor engines throughout Starships flip burn, SpaceX might basically perform a midair fixed fire, providing the rockets flight computer system a couple of seconds to analyze performance and downselect to the 2 healthiest engines for the final landing burn. With that change executed, Starship would theoretically have sufficient redundancy to land if just 2 of its three sea-level Raptors carried out nominally.
Further down the roadway, Musk states that SpaceX is working hard to improve Raptors deep throttle efficiency, potentially enabling future Starships to burn two– or even three– engines all the method to touchdown for a lot more redundancy. Deep-throttling large, complex rocket engines is extraordinarily difficult, though, so that upgrade is likely no less than several months away. In the meantime, Starship SN11 is effectively complete and Starships SN15 through SN18 are being assembled to support an unrelenting flight test campaign as SpaceX works towards orbital flights.
As formerly gone over on Teslarati, Elon Musk eventually revealed his opinion that SN9s engine-out failure was possibly preventable and that SpaceX would change the way future Starships try to land in a bid to add more redundancy.