With two successful 150-meter hops in the bag for SpaceX, Starship testing is preparing to enter the next phase. Starship SN6’s successful 150-meter hop followed just weeks after SN5’s achievement.
While SN5 is preparing to conduct another leap, Starship SN8 is closing in on its maiden flight, this time sporting three Raptor engines, a nosecone, and aero surfaces – likely to come after additional data is gathered via the upcoming SN7.1 Test Tank “Burst Test.”
The success of SN6’s test will have added additional confidence into numerous elements of the Starship prototype – ranging from structures to propulsion and controllability.
Chief Designer Elon Musk cited that repeating the tests will allow engineers to refine how they launch and land the vehicles, already observed via comparisons to Starhopper’s flight, SN5’s maiden launch, and then SN6.
Improvements to the processing flow surrounding the test are also improving, with SN6 conducting just a cryoproofing test and a Static Fire of Raptor SN29 before being cleared to proceed toward the hop.
Although SN6 was observed to be slightly leaning in post-landing footage, Starship’s legs do have the ability to cushion additional loading during landing, as was likely the case with SN6 returning under the power of a single Raptor (SN29) in an offset placement engine placement.
A peek at Starship SN6 on the landing pad at SpaceX Boca Chica. SN6 successfully completed a 150m hop on September 3rd. @NASASpaceflight https://t.co/j059JSQjL1https://t.co/9sTD7p0vVz pic.twitter.com/ek3rQi6rYS
— Mary (@BocaChicaGal) September 6, 2020
Despite thunderstorms over the local area on Saturday, engineers worked through the weekend to prepare SN6 for the return to the Production Facility.
The next prototype to greet Starhopper – the launch site’s permanent resident – is expected to be the SN7.1 Test Tank.
SN7.1 follows on from SN7, which was also a test tank and pushed to bursting point, on purpose. SN7.1 is a larger test tank and made from 304L-series stainless steel (or at least a variant of that alloy).
While not deemed to be the “final” alloy SpaceX is hoping to utilize on Starships and Super Heavy’s in the longer-term future, all previous Starships have been made from the 301-series alloy, whereas SN7, SN7.1, and all near-term future Starships are made from 304L.
As such, SN7.1 will provide vital data into how much pressure the tankage can withstand before failing – data that will be fed into SN8’s test program.
Work on completing the SN7.1 Test Tank at the Production Facility is all but finished, allowing for a roll to the launch site this coming week.
With two launch mounts available, it is yet to be seen if SN7.1 will take up residence on Starship’s regular mount, or the second test mount – or switch between the two. SN7.1’s test regime is likely to include cryoproofing and load tests before being pushed to bursting point.
Starship SN5 is expected to hop at least one more time, with processing at the Production Facility readying her for rollout to the pad after SN7.1 has completed the trip.
SN5 is likely to follow SN6’s refined test regime of a cryoproofing test, a Static Fire test, followed by a 150-meter hop.
At present, SN5 remains located outside of the Mid Bay, acting as a pretend supervisor to the High Bay construction efforts that are now towering above her.
It is unknown if SN5 is still hosting – or will once again utilize – Raptor SN27 for the second hop.
Starship SN8 will mark the next phase of testing as the first prototype to fly with three Raptor engines, a nose cone, and aero surfaces.
With SN5 making way for SN8’s final stacking operations inside the Mid Bay, this new Starship is now waiting in line for testing.
At present, SN8’s testing will have to wait until SpaceX has concluded the burst test objectives with SN7.1 and even the potential of a second hop with SN5.
Several interesting new items will be employed during SN8’s flow, such as the likely rollout of the nose cone separately, for mating with SN8’s tankage at the launch site.
SN8 will also mark the first time three Raptor engines will have been fired on a Starship.
The test launch’s initial altitude target is yet to be confirmed.
With an allowance to launch to 20 KM, SN8 could be launched to a lower altitude at first, with incremental testing as Starship conducts her first-ever horizontal drop toward the launch site before the Raptors push the aft vertical for a touchdown.
Once SN8 rolls out of the Mid Bay, sections for SN9 will begin stacking. The assembly of this future Starship is known thanks to footage of sections now in final preparation outside of the “Big Tent” production buildings by the ever-vigilant Mary (@bocachicagal), NSF’s Boca Chica photojournalist and a long-time local resident.
The most recent milestone was the sleeving of SN9’s Thrust Dome and a five-ring stack with stringers – that will connect SN9’s tank section to the nosecone – spotted out in the open.
SN9’s role is potentially akin to SN5 and SN6’s relationship, backing up SN8 for the evolved test regime.
SN10 and Future Vehicles:
With hardware such as Thrust Pucks, Downcomers, and landing legs arriving almost every second week – along with various bulkheads and ring welding being worked on inside the “Big Tents”, it was always likely that even more Starships were being born.
Confirmation came via the sighting of hardware labeled SN10 arriving into Boca Chica last week.
While it can only be speculated as to what test regime SN10 will undergo, it does confirm the ever-increasing production cadence at SpaceX Boca Chica.
Although Super Heavy labeled hardware is yet to be seen out in the wild, vast numbers of steel rings are being staged at Boca Chica, which could prove to be the steel that will be used to create the rings for what will initially be a dual-Raptor prototype booster.
This initial Super Heavy booster will be stacked inside the new High Bay, which is now just waiting for its roof section. It will then head to the under-construction mount at the Orbital Launch Site for its own hop test.
The initial testing of prototype Super Heavy vehicles will pave the way for additional refinements to the full stack booster, which – likely thanks to impressive test results at SpaceX McGregor – is now set to host 28, rather than 31, Raptor engines.
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