https://www.nasaspaceflight.com/2021...heavy-waiting/
...
SpaceX will be hoping SN10 is third time lucky, per nailing a landing. SN8 and SN9 both achieved numerous test objectives – such as controlled ascent and a stable bellyflop return before SN8 suffered engine issues due to a loss of pressurization in the CH4 Header Tank during the landing burn and SN9 failed to ignite one engine during the flip maneuver due to an apparent ignitor issue.
Mitigation of both SN8 and SN9’s issues have been implemented, with helium pressurization of the Header Tank dealing with the former and firing all three Raptors during the flip on SN10, before deselecting the engine with the least lever arm in the event of all three Raptors firing up during the flip.
Should all go to plan with the latest attempt, SN10 will get to plant her landing legs into a resurfaced and expanded landing pad.
Thanks to the accuracy of the SN8 and SN9 returns, the resulting RUDs (Rapid Unscheduled Disassemblies) have caused some damage to the pad requiring repairs. Ahead of SN10, the entire pad was expanded and laid with rebar before being surfaced with fresh concrete on Sunday.
How long that concrete takes to cure was the subject of social media speculation and may ultimately be the deciding factor when SN10 launches.
SN11 to SN19:
Starship SN11 is all-but ready to make the trip to the launch site following the completion of its processing flow inside the High Bay.
Now with a nosecone and its aero surfaces installed, the option to take the trip and host the vehicle on Pad B has not been taken at this time but will remain an option if SN10 doesn’t launch by the end of the coming week.
SN11 is a near mirror to her older sisters, albeit with an additional amount of
TPS (Thermal Protection System) patches on the vehicle’s windward side. Pending the results of SN10, this vehicle could launch relatively soon after taking the trip down Highway 4.
SN11 marks the final vehicle that will fly without the additional modifications that resulted in the scrapping of SN12, 13, and 14.
Starship SN15 will follow SN11 and will sport several improvements – some of which are unknown. What has been spotted is a new design for the Thrust Puck, while SN15 onwards will host a greater amount of TPS.
SN15’s nosecone is already being prepared, allowing for the stage to be set where this vehicle will take over the position in the High Bay once SN11 vacates it for the trip to the launch site.
SN15 will mark the next range of Starships currently in various stages of preparation at the Production Site, with parts ranging up to SN19 already spotted by
Mary (@bocachicagal).
The stacking of SN16 will soon follow the same path as SN15, with the work taking place inside the Mid Bay. This vehicle already has all its tankage sections ready for mating, with its leg skirt making an impression of a roller skater by being wheeled around with its legs deployed.
SN17 and SN18 are also building up the sections required for stacking later, while SN19’s is only a CH4 Header Tank at this stage. However, the fact they are already working on parts for SN19 is, in its own rights, an astonishing sign of Boca Chica’s production cadence.
What is even more interesting is the evolution of what these future Starships will look like, in turn providing clues to their test regimes.
One section inside a production tent appears to be undergoing preparations to cover the entire windward side in TPS. This unnamed section could indicate a vehicle that will be taken to an altitude that would test its heat shield under re-entry conditions. Current TPS patches are mostly being tested to see how they perform during the stresses of cryogenic propellant loading and launch and landing vibrations.
Super Heavy:
Even more impressive is the quiet build-up of
the first Super Heavy vehicle, known as BN1. This vehicle could conceivably head to the launch site before the likes of SN19 take the road trip. It is understood that BN1 would be hosted at one of the Starship launch site mounts, Pad A or Pad B, and may only be used for ground testing.
BN1 is now moving into the second phase of stacking, with the aft section moving into the High Bay for integration with the first half of the booster stack.
Rolling BN1 to the launch site for ground testing would allow for valuable data related to pressure and cryo-testing. It could then have Raptors installed for a Static Fire test and even a 150-meter hop, as Elon Musk originally noted. At the time, and likely now outdated by the ever-evolving plan for Starship/Super Heavy, Elon noted a two-engine hop. BN1, however, has the capacity to host four Raptors.
BN2, meanwhile, is already showing signs it’s a step further down the line of testing, with the Forward Dome sporting an additional support ring that will provide structural reinforcement.
The plans for BN2’s test regime are unknown at this time. However, once additional sections have been spotted heading into the High Bay, all eyes will be on the aft end to gain an idea into how many Raptors it will host.
Super Heavy will eventually sport
28 Raptors. That full-power version of the booster, which – due to the rocket’s sheer power – will utilize one of two sea platforms, Deimos and Phobos.
The initial Super Heavy rockets, at least, will launch from the Orbital Launch Site that is continuing to be built up next to Starship’s two pads.........
