Starship SN9 speeds toward Static Fire and test flight

by Chris Bergin

With Starship SN8’s test flight still fresh in the memory, SN9 is set to complete an accelerated pad flow with a Static Fire test and launch this coming week. A triple Raptor Static Fire test occurred Wednesday, although it appeared to be a shorter firing than required, thus a second Static Fire test is expected on Thursday. Pending acceptable test results, the launch of SN9 could take place just a few days later, likely at the weekend.

Meanwhile, Starship SN10 is now an integrated stack inside the High Bay, ready to roll to the launch site as soon as SN9 departs. SN11 and SN12 are undergoing their own buildup operations inside the Mid Bay, with the former only lacking a nosecone.

Starship SN9:

Despite requiring the replacement of two damaged aero surfaces, following a topple in the High Bay, Starship SN9 has already successfully proven a reduction in the processing and pad flow timeline – when compared to SN8 – in preparation for this upcoming test flight.

This is one of the objectives for utilizing numerous Starships, allowing rapid production and launch capability that will be a major factor in the big picture of launching what Elon Musk notes will be a vast amount of vehicles to build a base on Mars.

“Production is hard, prototypes are easy,” Elon noted on Twitter. “Building ~1000 Starships to create a self-sustaining city on Mars is our mission.”

SN9’s pad flow involves two key tests, the first of which has now been completed.

Known as proof-testing, Starship SN9 was put through two tests, one seeing the vehicle filled with gaseous nitrogen – called the ambient test – ahead of being loaded with super-cold liquid nitrogen (LN2) for the cryo test.

An impressive test of Starship’s Reaction Control System (RCS) was also undertaken.

Spread over two days, the tests proved SN9 could be pressurized under cryogenic propellant loading conditions, allowing for the progression towards a major pre-launch objective – the Static Fire test. Ahead of the test, on Monday, minor testing was ongoing – likely relating to Header Tank testing – requiring the pad to clear.

For the Static Fire test, Starship SN9 was fueled with its cryogenic beverages of choice, Liquid Methane (CH4) and Liquid Oxygen (LOX).

Akin to a normal countdown, a Static Fire test is the same as a Wet Dress Rehearsal, bar the obvious addition of firing up the engines for a few seconds, to gain the required data on the performance of the Raptors and the vehicle, along with the associated Ground Support Equipment (GSE) plumbing.

As per usual with a Static Fire test, such as those conducted on Falcon 9 rockets a few days before launch day, a “quick look” review will be conducted into the vehicle’s performance, data that is then fed into the Launch Readiness Review (LRR). Due to the shorter than expected firing, a second attempt is expected on Thursday.

With the current thinking pointing towards launch just a few days after the Static Fire test, that review will take place in short order after the test.

No official launch date has been mentioned by Elon or SpaceX – with the latter leaving most of the official Starship official updates for the boss to filter into social media. However, clues can be gained via local documentation, from road closures to restricted land, air, sea notices, and even hand-delivered letters to local residents.

A filed TFR shows opportunities on Friday, Saturday, and Sunday.

Starship SN9 will be targeting a repeat of the SN8 test, albeit this time with the goal of landing in one piece.

SN8’s test was a huge success, despite the explosive finale. The vehicle successfully conducted numerous first-time milestones, with only the loss of thrust from the re-lit Raptors causing the landing burn to fail and the hard landing.

Mitigation of that landing burn issue, which was blamed on the CH4 Header Tank losing pressure, has been implemented into SN9.

“SN9 will press CH4 header tank with helium,” noted Elon, responding to Tim Dodd on Twitter. “Long-term solution is under debate. Not clear what is lightest/simplest.”

Once again, expectations should be calibrated towards the fact this will only be the second-ever flight of a full-stack Starship. Numerous elements of the flight could fail well ahead of any attempt to nail the landing.

However, thanks to SN8’s flight, there is now a roadmap of what to expect during the flight profile diluting some of the universal “eek” incurred during what appeared to be a Raptor failing a few minutes into the flight.

It was later known that was a planned shutdown, akin to Starship’s version of “in the bucket” as seen during the Shuttle era where a third of the thrust was removed to allow the orbiter to pass through MaxQ (Maximum area of aerodynamic stress), before then ramping back up to full power. That thrust profile’s graphic is in the shape of a bucket. Starship’s graph would be more like a flight of stairs.

While Starship wasn’t even close to going transonic, the shutdown of the first and then second Raptor was the vehicle’s flight profile requirements to smoothly reach its 12.5 KM target and not head on its merry way toward Mexico with three roaring Raptors, even at reduced thrust. For SN9, this staggered shutdown sequence will now be an expected event.

Ahead of the Static Fire test and launch, the remains of SN8 are being cut up ahead of clearing the landing pad in expectation of SN9’s landing on its concrete surface, in what could be just a matter of days away.

Future Starships Lining Up:

Continuing the well-known SpaceX Boca Chica production cadence, the result of Starship SN9’s test won’t hamper the flight schedule – providing SN9 doesn’t opt to dive into the Tank Farm.

Starship SN10 is all-but ready to roll to the launch site following its nosecone mating inside the High Bay.

Although the High Bay was specifically designed to cater to the height requirements to stack Super Heavy boosters, it is proving to be a very useful facility for removing the need to install the nosecone at the launch site.

Notably, that may have been the plan all along, with what appears to be room for four stacks, based on the BN1 Super Heavy sections already deeper inside the High Bay.

Based on the production flow of Starships, where nosecone aero surface installation and stacking with its own five-ring section takes place inside the Windbreak facility, and the Mid Bay catering for two Starships to be stacked, there is a real possibility SpaceX Boca Chica could have three fully stacked Starships available at any one time.

This is aided by two launch mounts, Pad A and Pad B.

At present, Starship SN11 is now stacked and is just waiting for SN10 to depart from the High Bay to receive its own nosecone. SN12 is now being stacked alongside SN11 in the Mid Bay.

Sections through to Starship SN17 have been spotted by Mary (@bocachicagal), as overviewed by Brendan’s updated graphics.

@brendan2908 latest round up on the sections of Starship and Super Heavy.

Based on this cadence, the potential for launching two Starship prototypes a month is already a possibility, starting with SN9 and SN10 – both of which are at the point of their respective flows that allows for them both to launch in January.

Elon Musk has already hinted at the dual pad use of Pad A and B, allowing for two Starships to be out at the launch pad at the same time. A third could then receive its nosecone in the High Bay.

Super Heavy boosters would still be able to conduct their own flows, based on the High Bay’s available capacity and its own dedicated launch mount next door to the Starship launch site.

(Left to Right) Pad B, A, and Super Heavy Mount – via Mary (@bocachicagal)

This conveyer belt of vehicles was always the plan. However, seeing it, in reality, continues to astonish observers previously used to multi-year flows for brand new rockets to be built and head to the launch site.

Most photos via Mary (@bocachicagal)

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