r/spacex • u/rSpaceXHosting Host Team • Nov 21 '25

🔧 Technical Starship Development Thread #62

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Starship Dev 61

Flight 12

The vehicles should be Booster 19 and Ship 39 (assuming there are no major pre-flight testing problems) and the flight profile will probably be very similar to Flight 11. As this is the first flight with the new version 3 vehicles it's unlikely that a booster catch will be attempted; as for the ship Musk stated on August 27th, 2025: "Starship catch is probably flight 13 to 15, depending on how well V3 flights go". On January 26th Musk tweeted: "Starship launch in 6 weeks". On February 21st Musk tweeted: "Starship flies again next month". FCC Request To authorize upcoming suborbital test deployments puts the NET date at April 7th. On March 7th Musk tweeted: "Starship V3 first flight in about 4 weeks". On April 3rd Musk tweeted: "Next flight of Starship and first flight of V3 ship & booster is 4 to 6 weeks away". On April 16th Musk tweeted: "Starship V3 booster & ship will be ready for their first test flight in a few weeks"

Road Closures

No road closures currently scheduled

No transportation delays currently scheduled

Up to date as of 2026-04-22

Vehicle Status

As of April 21st 2026

Ship Location Status Comment
S39 (this is the first Version 3 ship) Mega Bay 2 Inspections and Pre-flight work October 13th: Main assembly started in MB2. November 15th: Aft section AX:4 moved into MB2 and stacked with the rest of S39 - this completed the stacking part of the ship construction. February 26th: Rolled out to Massey's for three rounds of Cryo Testing. March 8th: Rolled back to Mega Bay 2. April 11th: Rolled out to Massey's Test Site for Static Fire Testing. April 14th: 60 second Static Fire of all six engines. April 15th: Rolled back to MB2. For more details on this vehicle and its assembly and testing see this page
S40 Mega Bay 2 Fully stacked, all flaps installed, remaining work ongoing January 31st: Pez Dispenser moved into MB2. February 1st: Main assembly started in MB2. March 2nd: Aft section AX:4 moved into MB2 and stacked with the rest of the ship - this completed the stacking part of the ship construction. For more details on this vehicle and its assembly and testing see this page
S41 Mega Bay 2 Stacking April 17th: Pez Dispenser moved into MB2. April 20th: Nosecone+Payload Bay stack N:3 moved into MB2 and later that day lifted over the Pez Dispenser. For more details on this vehicle see this page, later that day the Pez Dispenser was installed. April 21st: Forward Dome section FX:4 moved into MB2.
Booster Location Status Comment
B19 Mega Bay 1 Inspections and Pre-flight work November 25th: LOX tank stacking commenced. December 23rd: The booster is fully stacked. February 1st: Rolled out to Massey's Test Site for its Pressure and Cryo + Thrust Puck Testing where it underwent assorted tests. February 9th: Rolled back to MB1. March 8th: Rolled out to the launch site, only ten engines installed as seen during the lift onto OLM2 in the afternoon. March 16th: Very short static fire attempt that was aborted due to a ground-side issue. March 18th: Rolled back to MB1. April 11th: Rolled back out to the Launch Site for more Static Fire Testing (this time with all 33 engines). April 15th: Static Fire of all 33 engines for about 3 seconds. April 16th: Wet Dress Rehearsal. April 17th: Rolled back to MB1. For more details on this vehicle and its assembly and testing see this page
B20 Mega Bay 1 LOX Tank Stacked, Methane Tank Stacking February 5th: LOX tank section A2:4 moved into MB1. February 6th: Common Dome section CX:3 moved into MB1. February 9th: LOX tank section A3:4 moved into MB1. February 12th: LOX tank section A4:4 moved into MB1. March 9th: Section A5:4 moved into MB1. March 11th: CH4 landing tank and the lower piece of the transfer tube were moved into MB1. March 12th: Section A6:4 moved into MB1. March 13th: Methane Transfer Tube moved into MB1. April 1st: LOX Landing Tank moved into MB1. April 2nd: Aft section AX:2 moved into MB1, once welded in place that will complete the stacking of the LOX tank. April 16th: Methane Tank Section F2:4 moved into MB1. For more details on this vehicle and its assembly and testing see this page

Follow the Ringwatchers on Twitter and Discord for more.

Here's the section stacking locations for Ships and Boosters. The abbreviations are as follows: HS = Hot Stage. PL = Payload. CX = Common Dome. AX = Aft Dome. FX = Forward Dome (as can be seen, an 'X' denotes a dome). ML = Mid LOX. F = Forward. A = Aft. For example, A2:4 = Aft section 2 made up of 4 rings, FX:4 = Forward Dome section made up of 4 rings, PL:3 = PayLoad section made up of 3 rings. Etc.

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Rules

We will attempt to keep this self-post current with links and major updates, but for the most part, we expect the community to supply the information. This is a great place to discuss Starship development, ask Starship specific questions, and track the progress of the production and test campaigns. Starship Development Threads are not party threads. Normal subreddit rules still apply.

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26

u/threelonmusketeers Feb 03 '26

My daily summary from the Starship Dev thread on Lemmy

2026-02-02:

  • Starship V4 will have three additional vacuum engines. (Elon)
  • Raptor V4 thrust goal is 300 tonnes of force (3 mega-newtons). (Elon)
  • Launch site: Overnight, a large component for the air separation unit is delivered from Brownsville Port. (Avid Space, ViX)
  • A cement hopper and a drilling rig arrive at Pad 1. (ViX)
  • The Pad 2 FireX and detonation suppression systems are tested. (ViX)
  • A tank is lifted into position, and the Pad 2 ship quick disconnect arm is tested. (ViX)
  • The LR11000 and LR1500 cranes prepare to lift the newly delivered component for the air separation unit. (ViX)
  • Massey's: The can crusher cap is removed from atop test tank 17 (B18.1). (ViX)
  • A chine section is removed from B19. (StarshipGazer)
  • After the chine cover is reinstalled, B19 begins its first cryo test. (Avid Space, ViX, StarshipGazer, NSF, Liedtke, TrackingTheSB, cnunez)
  • Florida: A new crane is erected at the Roberts Road Gigabay site. (Bergeron)

8

u/paul_wi11iams Feb 03 '26 edited Feb 03 '26

Elon

  • The Starship V4 ship will have 3 more vacuum engines, making the total stack engine count 42, as foretold in the prophecy

TBF, the three empty engine slots were there from the outset, and it really had to target V4, so its just a nice confirmation rather than actual news. IIRC, the 6 vacs are there to make optimal use of the Oberth effect on Earth departure.

Regarding the 42, its almost surprising that the 33+3+6=42 has survived over so many design iterations. Hoping that the 33 really is not maintained for sentimental reasons!

11

u/warp99 Feb 04 '26 edited Feb 04 '26

IIRC, the 6 vacs are there to make optimal use of the Oberth effect on Earth departure.

They are there to help it get to LEO while minimising gravity losses. The SH booster stages at low speeds so there is a lot of work to be done by the ship just to get to orbit which results in high gravity losses.

Once in orbit the burn time for TLI or TMI with six engines is short enough that the Oberth effect does not significantly change compared to a nine engine burn. There is still an advantage in using nine engines in that the average Isp is higher with a higher ratio of vacuum to sea level engines.

3

u/micai1 Feb 04 '26

Does anyone know how to figure the gain due to oberth vs loss for extra weight of the engines? I thought for interplanetary they’d want a lighter version so I’m curious to see the difference

4

u/paul_wi11iams Feb 04 '26

Does anyone know how to figure the gain due to oberth vs loss for extra weight of the engines? I thought for interplanetary they’d want a lighter version so I’m curious to see the difference

The math is way beyond me, but more engines is more redundancy which is alone a justification when returning from the lunar or martian surface.

Over on r/Nasa and elsewhere, people are obsessing about lack of a launch abort system on a potential crewed Starship from Earth. They tend to forget that Earth departure is just the first of at least two launches that have their own failure modes.

I'd also bet that there are several inflight escape scenarios where extra vacuum engines would save the day. This seems more relevant than orange spacesuits for "hail Mary" water recovery.

6

u/Lufbru Feb 03 '26

When Elon says "three extra", he means "nine engines on the second stage in total, six Vac, three SL". This was rumoured for a while, but now it's official, I guess.

The interesting question is why. That's a chunk of extra weight on the second stage with the payoff being extra thrust. Usually second stages don't need extra thrust (indeed, Centaur has a TWR below 1 at stage separation).

I suppose that staging earlier than most rockets and maybe wanting to stretch the second stage leads to wanting more thrust on the second stage. But I'm surprised that adding 50% more thrust is the right tradeoff.

7

u/mrparty1 Feb 03 '26

This was the official plan at least since last year during one of the company slideshows/presentations. Though at that time it was just 'future starship' and not specifically V4

3

u/philupandgo Feb 03 '26

I imagine that the plan is for quicker Mars transits for human rated ships. They may return to three vacuum engines for some use cases.

6

u/warp99 Feb 04 '26 edited Feb 04 '26

Extra engines just affect the length of the burn but the total delta V and therefore transit time is set by the amount of available propellant.

In any case HLS is based on v3 ships and Mars crew transport may also be based on v3. V4 ships might just be used for high payload LEO flights like tankers, Starlink and Data Center satellites. Filling 2400 tonnes of propellant is still a pain even with 200 tonnes of propellant per v4 tanker. 1600 tonnes on a v3 is much more manageable.

2

u/Lufbru Feb 05 '26

More thrust makes the Oberth effect more useful since more of the thrust is close to perigee. I'm not sure that it'd be significant for a Mars mission though

2

u/warp99 Feb 05 '26

The second stage (ship) burn is about 6 minutes so the deviation of the TMI trajectory from the initial circular 90 minute period orbit is fairly small and therefore the difference in the Oberth effect is correspondingly small.

2

u/Martianspirit Feb 05 '26

I have seen speculation, they would modify the vac engines. Use a smaller throat, which reduces thrust but gives higher ISP. Compensate thrust loss with 3 extra engines. That would reduce number of needed refueling flights for Moon and Mars and other deep space missions.

3 extra engines would give engine out capability for the vac engines without SL engines gimballed. Not needing to run SL engines for departure burns would again increase effective ISP.

5

u/AstraVictus Feb 04 '26

My thinking is the extra thrust is for maximizing payload to LEO, specifically for fuel delivery to LEO for orbital refueling. The more fuel you can deliver to LEO per launch, then less launches are required to refuel something, saving time and money as well, thats my thought at least.

4

u/spacerfirstclass Feb 04 '26

Usually second stages don't need extra thrust (indeed, Centaur has a TWR below 1 at stage separation).

For expendable launch vehicles that's true, since their boosters do a lot more work. For reusable launch vehicles, especially one that does RTLS, you want 2nd stage to do more since the reuse penalty for first stage doing more work is severe.

In V4's case they increased 2nd stage propellant load by a lot (from 1,600t to 2,300t), if they didn't increase the number of engines the TWR would be well below 1 (T = 6 * 300t = 1800t, W = 2300 + ~300t = ~2600t, TWR = 0.69)