Starship SN11 will re-attempt a Static Fire test Thursday – following a scrub on Monday – ahead of a potential flight as early as the weekend or the start of next week. Forever subject to change due to numerous considerations – ranging from weather, hardware parameters, and paperwork approval – SN11 will mark the final test of this iteration of Starship before the program moves into the next phase of testing.
Following SN11’s flight, SpaceX will move on to SN15, 16, and 17, alongside testing with Super Heavy prototypes BN1 and BN2, before shooting for an orbital launch with SN20 and BN3. In typical SpaceX-style, that orbital launch has an astonishing – and unlikely – “by July 1” target. At the very least, this target portrays SpaceX’s Starship drive to push the vehicle into operation.
This will be the fourth high altitude test flight of the prototype Starship, and while efforts continue to focus on refining the landing element of the flight profile, the vehicle has already achieved numerous milestones, including proving long-duration Raptor performance and controllability during ascent and the stable “bellyflop” return under the control of its aero surfaces – a huge test flight objective.
SpaceX Boca Chica, meanwhile, has pumped out Starships with such high cadence as to allow for fast turnarounds after each launch, implementing tweaks to the vehicle ahead of the next flight.
SN8 achieved the flip maneuver before losing thrust due to the Methane (CH4) Header Tank losing pressure during the landing burn, SN9 did not complete the flip due to engine relight issues, and SN10 completed all the maneuvers before landing hard – eventually resulting in the vehicle exploding several minutes after touchdown.
The mitigation path for these issues focuses on those final few seconds of flight.
Post SN8, SpaceX opted to add helium pressurization to SN9’s CH4 Header Tank. After SN9’s engine relight issue, SpaceX opted to light all three engines during SN10’s flip and burn before deselecting the engine “with the least lever arm” in the event all three successfully relit.
Starships – three unique side-by-side cool clips from Mary, syncing the moment of Raptors' ignition prior to landing. @NASASpaceflight @SpaceX @BocaChicaGal https://t.co/5iseEE9ihu pic.twitter.com/v9QaTU8dN4
— Jay L. DeShetler (@jdeshetler) March 8, 2021
Indeed, all three engines did relight during SN10’s flip before the system deselected to land on just one engine. While the landing velocity looked visually acceptable, SpaceX CEO and Chief Designer Elon Musk soon confirmed it was still too high.
Additionally, a few of the landing legs did not lock into place, although Elon noted the high velocity landing would have seen them squashed regardless. Notably, Elon noted the hard landing was due to the Raptor – conducting the landing burn -ingesting helium that was pressurizing the CH4 Header Tank.
Fair point. If autogenous pressurization had been used, CH4 bubbles would most likely have reverted to liquid.
Helium in header was used to prevent ullage collapse from slosh, which happened in prior flight. My fault for approving. Sounded good at the time.
— Elon Musk (@elonmusk) March 9, 2021
It’s not clear what refinements are being made for SN11’s flight, other than Elon’s comment that multiple fixes are in work.
One change likely during SN11’s landing is the use of two engines instead of down-selecting to just one as a way to counter potential loss of thrust and increase redundancy during the no-room-for-failure landing burn.
Regardless of flight changes, SN11’s test campaign during its pad flow has so far been going mostly to plan, with proof testing already complete under both ambient and cryogenic conditions.
The Static Fire test was expected by the end of last week. However, issues – understood to be related to GSE (Ground Support Equipment) – delayed the firing of SN11’s Raptors, with the weekend not available for testing due to the requirement to close Highway 4 during such tests. SpaceX only requests a handful of weekend road closures to keep local disruption to a minimum.
The latest Static Fire window was set for Monday morning, with the potential to launch the following day. However, this was pending acceptable weather conditions.
Despite the foggy conditions, SN11 did attempt the test, before aborting shortly after preburner ignition. Another attempt is set for NET (No Earlier Than) Thursday morning.
The FAA (Federal Aviation Administration) formally authorized the SN11 flight, as reported from the Washington Post’s Christian Davenport on Monday.
NEW from the FAA: The FAA has authorized the SpaceX Starship SN11 flight. BUT the SN10 mishap investigation remains open. Could see a static fire as early as today. https://t.co/ZRAT8nqbWM
— Christian Davenport (@wapodavenport) March 15, 2021
Following the launch of SN11, SpaceX will move on to Starship SN15 – bypassing SN12, 13, and 14 – as previously reported by NASASpaceflight.com.
SN15 includes a new Thrust Puck design and other – mostly unknown – improvements. It will likely sport additional Thermal Protection System (TPS) as part of the heatshield test program.
This vehicle is currently in the Mid Bay, awaiting its turn to enter the High Bay for nosecone stacking. Currently, the High Bay is occupied by the two large tankage sections for the first Super Heavy prototype, BN1.
BN1 is not expected to fly. Instead, it will be stacked and rolled to the Starship suborbital pad for ground testing, including a potential Static Fire test. This will provide vital data ahead of the test flight of BN2, of which sections have already been spotted waiting for stacking.
The BN1 test campaign is expected to occur before SN15 goes to the pad for its test flight.
According to documented information seen by NASASpaceflight, BN1, BN2, and the new Starships represent “iterative improvements to the vehicles to improve the design and serve as production pathfinders” to aid the increasing production cadence.
It is also possible that SpaceX will skip further production of the SN18 and SN19 Starships based on those vehicles not being referenced. This would match how SN12, 13, and 14 were also scrapped as SpaceX opted to advance from SN11 to SN15.
Notably, the information seen by NASASpaceflight – and always subject to change – also adds a fascinating note about the first orbital flight, which is cited as involving Super Heavy BN3 and Starship SN20, “with a goal to get to orbit by July 1”.
While that date is highly ambitious at best, it proves SpaceX’s drive to send Starship into orbit “this year” as an absolute target. However, Elon did confirm “that’s our goal” when questioned on Twitter.
This goal is also backed up by visual work taking place both on the vehicles and at the launch site.
With TPS application on patches of current Starships being used to test how the material and its attach points react during prop loading and flight stresses, entire sections of future Starships are being covered in the hexagon tiles.
This process – covering the vehicle’s entire windward side – will be required for missions that will see Starships return from space and endure reentry heating.
It is also entirely possible that a Starship ahead of SN20 will receive a large amount of TPS to increase performance data before SN20’s flight into space.
A huge amount of work is also taking place over at the Orbital Launch Site.
This site will eventually host two Super Heavy mounts, with the first already waiting for its launch table and the construction of a huge integration tower that will include a crane to lift and mate Starship with the booster while on the mount.
Just last week, the first of the new propellant tanks arrived at the launch site, ready to quench the thirst of future Super Heavy boosters.
The aforementioned information also noted that the Orbital Launch Pad would indeed be capable of catching the booster in lieu of having landing legs, as previously noted by Elon on social media. This would involve catcher arms on the Integration Tower. This is unlikely to be ready in time for BN3’s flight, if SpaceX continues to target BN3 for the orbital mission, given plans are continually changing at SpaceX Boca Chica.
Despite the impressive construction pace at the launch site, being ready for a BN3/SN20 launch “by July 1” can be all-but ruled out. However, with the Integration Tower potentially a week or so away from rising out of the ground, the potential of an orbital mission later this year is now becoming almost a certainty.
Most content via Mary (@bocachicagal)
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