Starship SN9 has made a quick recovery from engine issues suffered during last week’s trio of Static Fire testing, placing the possibility a launch could occur this week. Providing SN9 and her two replaced engines perform without issue during one final Static Fire test on Monday, SN9 will have passed all the hardware requirements to allow SpaceX to set a launch date – expected to be classed as NET (No Earlier Than) Tuesday.
SN9 “Final” Static Fire:
Starship SN9 was aiming to provide a streamlined pad flow when compared to the testing undertaken by SN8. With proof testing under ambient and cryogenic conditions completed ahead of a triple Raptor Static Fire test, that goal remained on the cards.
However, SN9’s three Raptors did not fire for the required duration, ultimately demanding the test be repeated last week.
With the Tank Farm replenished and the relevant road closures filed, SN9 once again began fueling operations with the expectation this would clear the path for a launch date to be set later in the week.
Notably, after the first ignition was observed, the characteristic double vent was absent. As such, SN9 was not pushed into the usual detanking operations following the test.
Instead, SN9 was recycled for another Static Fire test, with Elon Musk noting on Twitter: “Today at SpaceX is about practicing Starship engine starts. Two starts completed, about to try a third.”
This process relates to the opportunity to test “rapid refueling and reuse” as part of Starship’s overall operational design. Elon Musk stated in 2019 that Starship was being built to fly at least three times a day.
With the testing completed, observations were being made concerning two of the firings, which appeared to show only two of the three engines were firing during the second and third tests.
These observations were cross-referenced with the vents that begin spewing vapors from the vehicle’s aft at around T-12 minutes. One of the “tri-vents” appeared to be turned off, pointing to one engine being placed out of use for tests 2 and 3.
Although Elon commented that “All three static fires completed & no RUDs. Detanking & inspections now. Good progress towards our “Hop in & go to Mars!” goal,” it soon became apparent why one of the engines was not firing on the latter two tests.
One of the Raptors, believed to be SN44, suffered unspecified issues during the first hot fire. Subsequent inspections showed that “two of the engines need slight repairs, so will be switched out,” per Elon Musk.
Fears that such a process would push SN9’s launch date back by weeks were soon dismissed by the sight of new Raptors riding to the Launch Pad for swap-out processing.
As suspected, SN44 was the first engine to be removed, with two engines in total swapped out.
Interestingly, the turnaround pace – allowing for the Static Fire test window to be confirmed for Monday – was impressive, dismissing concerns of a lengthy delay to the launch date based on previous engine swaps during pre-launch testing.
I have received an ‘Alert’ notice and a road closure has been scheduled from 8 a.m. – 5 p.m. tomorrow. Possible static fire attempt of the three new Raptor engines on Starship SN9. @NASASpaceflight pic.twitter.com/tA09ZNIBbw
— Mary (@BocaChicaGal) January 18, 2021
However, the three Raptors now installed in Starship SN9 still need to perform a good Static Fire test before any launch date target is confirmed.
Thanks to the numerous tests that have now occurred with Starships, a Static Fire and Launch Countdown timeline has been produced by NSF’s Adrian “Spreadsheet Guy” Beil, allowing for visual countdown clues.
As per the notice to local residents for Static Fire testing, the customary police siren remains the biggest pre-ignition clue, although the siren failed to sound during one of the three Static Fire tests last week. Also, while it’s aimed to provide a T-10 minute notice, the timing can be off by several minutes, as the local Deputy covers a wide local area.
Pending a review of the vehicle and engine performance from the test, the path to launch will become clear. It is not inconceivable that the launch of SN9 could take place the following day, on Tuesday.
Starship SN9 will be targeting a near repeat of the SN8 test, albeit this time to land in one piece. However, this flight’s actual altitude target is currently up in the air (pun intended).
SN8 flew to an altitude of 12.5 kilometers – which in itself was a reduction from the original targets. Local weather conditions, specifically upper wind strength, may play into considerations to reduce the altitude and provide more windows of opportunity for SN9.
This won’t impact the test flight goals, given SN8 successfully conducted numerous first-time milestones, with only the landing burn the item that SN9 will hope to improve upon.
Mitigation of that landing burn issue, which was blamed on the CH4 Header Tank losing pressure, has been implemented into SN9.
Thanks to SN8’s flight, the staggered engine shutdown sequence during ascent will now be expected, as opposed to causing concern. All eyes will be on SN9 ability to conduct a smooth touchdown and land upright on the landing pad.
Although the delay to SN9’s expected launch date can be measured in days, the high production cadence down Highway 4 at the Production Site once again sees several Starships impatiently waiting to take their turn to head to the launch pad.
Starship SN10 has long since received her nosecone and aero surfaces during processing inside the High Bay and took a stance to roll to the launch site last week.
With two launch mounts and Elon’s noted envisioning of two Starships out at the launch site simultaneously, SN10 could technically take the trip at any time. However, it’s likely SpaceX wants to see SN9 prove its landing ability before risking RUD-related damage to SN10.
Over the Mid Bay, SN11 has completed stacking and is waiting for SN10 to depart to allow for her own nosecone installation.
However, next door to SN11 in the Mid Bay has become an item of interest, with the opening sections of SN12 believed to be staged for stacking. That was before a section marked SN15 was observed by Mary’s (@bocachicagal) camera lens.
With very few labeled sections for SN13 and SN14, there is some potential that SpaceX Boca Chica is looking to advance what will be the next evolution of Starship production techniques, which kick starts with SN15.
No official information on this forward plan has been noted by Elon, although he did “like” the tweet pointing out the promotion of SN15 in the Mid Bay processing flow.
This is a very interesting forward plan for Starship via Mary (@BocaChicaGal).
SN9 – on Pad B.
SN10 – in the High Bay.
SN11 – in the Mid Bay.
Now joined by…
SN15 – in the Mid Bay (previously thought to be SN12).
So, SN11, then SN15 (no 12, 13, 14).
— Chris B – NSF (@NASASpaceflight) January 8, 2021
It is also notable that Mary has spotted more sections for SN16 and SN17 than SN13 and SN14 at the Production Site.
Also, relevant to the next evolution with SN15, a new Test Tank is under construction.
Unofficially called SN7.2, this tank will likely be based on some of the 3mm thick 304L stainless steel that is a reduction from the standard 5mm thick steel utilized on the current Starships.
With a variety of additional testing hardware seen arriving on a truck this Sunday, the only question outstanding is when the new Test Tank will be taken out to the launch site for what is likely to be an overpressure test event, following in the footsteps of previous Test Tanks.
In total, the amount of construction and activity at SpaceX Boca Chica remains incredibly high, with the Super Heavy prototype BN1 vehicle still waiting to complete stacking operations inside the High Bay. Simultaneously, its launch site next door to the Starship facility continues to be a hive of activity.
Also, being able to feed this conveyor belt of silvery beasts will be aided by the construction of a propellant production plant at the Old Gas Well Lot site.
Large amounts of hardware have already arrived for assembly, including gas separators and a distiller, which will be used to produce LOX that would – and is currently – shipped in by a fleet of road tankers.
Although this facility is being built down the road from the launch site, a pipeline will likely be created between the two facilities, allowing for replenishing the Tank Farm ahead of testing and launches.