Ship 25 (S25)

Ship 25 (S25) was a Starship second stage prototype, which flew with Booster 9 (B9) on Starship Flight Test 2. Ship 25's testing campaign began in late October 2022. In May 2023, the testing campaign continued at the Massey's test site as the first ship prototype. In June, testing continued back at the launch site, despite being somewhat outdated compared to the newer prototypes.

S25 was the first ship to have used Hot Staging. This means that the ship's engines are ignited while it remains attached the booster. The vacuum Raptors are ignited first, followed by the sea level Raptors to avoid them directly thrusting onto the hot staging ring. Per Elon Musk, using this method the payload capacity is increased by 10%.

Ship 25 was the first starship to enter space, having reached an altitude of 149 Kilometers, surpassing the Karman line.

For full stack testing see Starship 9/25.

S25 engines 09 July 2023 Musk Twitter — S25 engine section with 3 sea-level Raptor engines and 3 Rvac engines

Timeline[]

Click to view the timeline:

14 February 2022: S25 fwd dome sleeve outside tents (3-ring).
15 February 2022: S25 nosecone barrel section spotted (5-ring).
16 February 2022: S25 common dome section spotted.
5 March 2022: S25? Common dome section in tent.
6 March 2022: S25 common dome section/segment and another nosecone spotted in same tent.
9 March 2022: S25 aft dome sleeve prepared for flipping (4-ring), flipped.
10 March 2022: S25 aft dome spotted, lifted onto sleeving stand; sleeved with 4-ring sleeve [flipped yesterday]; lifted off stand.
4 April 2022: Ship aft section moved into tent 3 by a crane (likely S25 aft section).
12 April 2022: S25 5-ring nosecone barrel section spotted in front of tent; S25 nosecone barrel stiffener removed, then moved into wind break (low bay); S25 aft section spotted in tent.
1 November 2023: S25 re-stacked on B9 for unknown reasons.
2 November 2023: S25 de-stacked from B9, presumably for FTS installation.
9 November 2023: S25 re-stacked on B9.
11 November 2023: Ship 25 destacked from Booster 9.
15 November 2023: S25 re-stacked on B9
16 November 2023: S25 destacked off of B9 following a grid fin actuation failure.
17 November 2023: S25 re-stacked on B9 following replacement of grid fin actuators.

Testing Campaign[]

Date	Test	Outcome	Details
28 October 2022	Ambient Pressure	Success	Ship 25 conducted an ambient proof test.
1 November 2022	Cryogenic Proof	Success	Ship 25 conducted a cryogenic proof test on both tanks.
2 November 2022	Cryogenic Proof	Success	Ship 25 conducted a cryogenic proof test on both tanks.
7 November 2022	Cryogenic Proof	Success	Ship 25 conducted a cryogenic proof test on LOX tank.
5 May 2023	Cryogencic Proof	Success	Ship 25 conducted a cryogenic proof test at Massey's test site with S26.1 on both tanks.
14 June 2023	Spin Prime Attempt	Aborted	Ship 25 was filled with propellant; a spin prime test was likely intended but aborted.
21 June 2023	Spin Prime	Success	Ship 25 conducted a successful Spin Prime test
26 June 2023	Static Fire	Success	Ship 25 conducted a static fire test of 6 engines successfully

28 October 2022 - Ambient Proof Test[]

Timeline according to LabPadre discord:

08:32 Road closed
09:32 Pad cleared
10:31 S25 venting its tanks
13:11 Cars to pad
13:21 Road opened

01 November 2022 - Cryo Proof Test[]

Timeline according to LabPadre and NSF streams:

09:00 Road closed
09:33 Pad clear
09:34 Grass vent
10:07 SoLS tank farm started to vent (slight vents earlier)
10:28 Cars to pad
10:46 Pad cleared again
11:00 OLS CH4 subcoolers frost started to form
11:17 SoLS tank farm spooled up, together with grass vent
11:39 Venting from OLS CH4 side increased
11:45 Cryo load on LOX tank started, CONDENSATION started to form (not gradually but, whole height of tank at the same time)
11:50 LOX tank small frost ring started to form
12:07 OLS tank farm venting on CH4 side stopped; frost on LOX tank at the left half started to increase
12:28-44 OLS tank farm venting on CH4 subcooler top - but not getting frosty yet
12:46-13:02 CH4 subcoolers top restarted, slowly getting frosty now
13:07-28 Only right CH4 subcooler active
13:20 Condensation on LOX tank increased again; SoLS LN2 tank started venting again
13:44 Frost on CH4 tank started to form
14:32-33 Depress vents on LOX and CH4 tanks (facing sideways)
14:40 Cars to pad (S24 still frosty)
14:46 Road opened

02 November 2022 - Cryo Proof Test[]

Timeline according to LabPadre and NSF streams:

08:56 Road closed
09:10 or earlier (fog): Minor SoLS tank farm venting
11:08 SoLS tank farm venting started a lot, Grass vent
11:19 Venting decreased
11:40 LOX tank frost ring started to form
12:08 Tank farm activity (near recondenser) picked up again
12:40 Frost on LOX tank nearly 3 rings high; condensation started to form above the frost line
12:58 Nosecone header tank slightly venting
13:30 LOX tank fully frosty (but likely only half filled)
15:16 Condensation on CH4 tank formed (only very small ring)
15:25 Double depress vents from both tanks; CH4 vents continued; grass vent restarted
15:29 SoLS tank farm active again
15:30 Condensation started to form above the frost line on CH4 tank
16:05 Condensation started to decrease
16:23 Depress vents from both tanks
17:45 Cars to pad
17:53 Road opened

07 November 2022 - Cryo Proof Test[]

Today, B7's CH4 tank was cryo testes, as well as S25's LOX. tank

Testing timeline according to LabPadre and NSF streams:

08:03 Road closed
08:43 Pad cleared
---B7 testing - See Starship 7/24
13:15 SoLS grass vent
13:23 Activity at SoLS started for S25 testing
13:53 S24 LOX tank frost started to form
15:08 LOX frost around 3 rings high
15:09 Condensation started to form on rest of LOX tank
15:58 LOX tank fully frosty
16:48 FIREX tested at OLM
17:48 Depress vents
18:42 Road opened

08 November 2022 - Roll Back[]

Timeline according to LabPadre discord:

05:16 LR11000X attached to S25
09:54 S25 lifted off SoLS pad A by LR11000X
10:05 S25 touched down on transport stand
---S24 destack operations, see Starship 7/24
15:16 LR11000X detached from S25
15:40 S25 started to move
16:02 Entered hwy 4
17:06 Arrived at production site
17:20 Entered high bay

14 January 2023 - Roll Out[]

Timeline according to LabPadre discord:

06:09 S25 left high bay
08:07 Left construction site
08:53 Arrived at launch site

17 January 2023 - Lifting[]

Timeline according to LabPadre discord:

03:34 S25 attached to LR11000X
07:25 Lifting started
07:58 Touched down on Pad B

23 February 2023 - Lift and Roll back[]

S25 was lifted off SoLS Pad B and rolled back to the build site ahead of rolling to Massey's test site the next night. Timeline according to LabPadre discord:

08:32 Lift started
15:18 LR11000X detached
15:26 Started to move away from Pad B
22:11 Entered hwy 4, rolling back to build site
23:31 Reached build site, parked in the ring yard

24/25 February 2023 - Roll Out[]

S25 was rolled from the build site to Massey's test site. Timeline according to LabPadre discord:

22:46 Started rolling out of the build site
02:05 Arrived at Massey's

05 May 2023 - Cryo Proof Test[]

SpaceX conducted a cryo proof test of S25 (and S26.1) at Massey's test site. Both tanks frosted up during the test.

16 May 2023 - Aborted roll out[]

Timeline according to LabPadre discord:

13:31 Detached from QD plate at Massey's test site, currently on the move
20:48 Resumed rolling towards hwy4
22:15 Entered hwy4
22:55 After waiting on hwy4, S25 turned around and headed back up Massey's road aborting the roll out

17–18 May 2023 - Roll out and lift[]

S25-roll-out-SpaceX-Twitter-18-August-23 — Ship 25 moved to a suborbital pad at Starbase for a static fire of its six Raptor engines.^[1]

Ship 25 was rolled out and lifted onto SoLS Pad B by LR11000X. Timeline according to LabPadre discord:

23:16 Roll out underway
01:45 Arrived at launch site
03:39 Attached to LR11000X via squid
13:15 Lift underway
13:42 Lift completed

14 June 2023 - Cryo Proof Test / Spin Prime Abort[]

SpaceX conducted a cryo proof test with propellant and possibly intended to conduct a spin prime test. However, they didn't spin prime test the engines and about 32 minutes after engine chill, depress started.

Timeline according to LabPadre and NSF streams:

12:06 Road closed
13:29 S25 venting
12:42 Pad clear
14:12 Car to pad (border patrol?)
14:44, 51 Minor grass venting started
14:53 Some venting from recondenser area started
14:58 Grass vent; Tank farm venting started (SoTF)
15:10 Possibly some minor condensation started to form at bottom of LOX tank
15:17 Vent near pad base started
15:21 More venting around the pad, engine chill lines getting frosty (there are two such lines)
15:32 Engine chill line frost disappeared; reappeared at 37
13:35 Cryo load started, frost on LOX tank started to form
15:41 Some vent
15:55. 56 S25 venting
15:58 Frost passed LOX hatch
16:03 LOX tank frost reached 1 ring
16:25 LOX tank frost reached 2 rings; LOX side of SoLS tank farm venting a lot
16:29 Engine chill vent at base from engine chill line started
16;35 LOX tank frost reached around 2.5 rings, rest tank getting condensation; filling stopped
16:37 Engine chill pipes venting
16:39-40 Nosecone venting on the whole length of the flaps
16:42 Regular nosecone vent spotted
16:49 Minor frost ring below the TPS tiles on nosecone spotted (Header tank)
16:53 Drone spotted
16:54-55 Several vents of S25
16:59 Long depress vents from LOX tank; possibly abort
17:00 Engine chill vent stopped
17:05 Flare stack started venting
19:32 Road opened

21 June 2023 - Flight like chill and spin prime test[]

S25 spin prime 21-July-2023 SpaceX-Twitter — S25 engine chill and spin prime

According to SpaceX "Ship 25 completed a flight-like chill and spin of the Raptor engine pumps, stopping just before engine ignition. As a result of the test, cryogenic liquid oxygen formed a visible cloud beneath the ship. This checked out vital systems in advance of the upcoming static fire."^[2]

Timeline according to LabPadre and NSF streams:

10:59 Road closed
12:15 Pad cleared
13:27 SoLS tank farm venting started near recondenser
13:31 Tank farm venting started from main tanks
13:40 Condensation formed
13:50 Venting on pad base started
14:08 Frost line on LOX tank started to form, cryo load started
14:55 LOX tank a bit more than 2 rings frosty (bit less than last week), condensation on rest of tank started
14:59 Some engine chill venting, stopped again
15:02 Engine chill started
15:06 Drone spotted
13:12-14 Header tank venting along both flaps, indicating header tank fill; small header tank venting continued
15:19 New vent in the center of engine skirt spotted
15:20 interesting vent on left flap, looking somewhat like the old engine chill vent, stopped at 15:21:55
13:24:35 Spin prime test
15:26 Long depress vent on both tanks
18:16 Road opened

26 June 2023 - Static Fire test[]

Static fire of all 6 engines of S25^[3]

On 26 June 2023, SpaceX conducted a successful static fire of all 6 engines.^[4] According to Elon Musk, it looked good.^[5] Timeline:

14:57 Pad clear alarm/announcement
15:02 Road closed
15:07 Tank Farm activity (no lox or ch4 recondensor)
15:26 Flap actuation test
15:38 Pad clear
16:26 Tank farm activity stopped
17:02 CH4 recondenser activity
17:09 Tank farm activity
17:33 CH4 recondenser active again
17:34 LOX recondenser activity
17:51 LOX loading has started
17:54 Venting at engine chill lines
19:04 Engine chill has started
19:16 Header tanks venting
19:27:18 STATIC FIRE
19:29:46 Depress venting (detanking)
21:45 Road reopened

05 August 2023 - Lift[]

Timeline according to LabPadre discord:

07:09 Lift by LR11000X started
07:17 Touched down on transport stand
15:21 Lifting squid being removed
17:53 Detached from LR11000X

06 August 2023 - Roll Back[]

Timeline according to LabPadre discord:

1:18 Move of S25 observed
2:36 arrived at rocket garden, where SN15 once stood

05 September 2023 - Stacking[]

Timeline according to LabPadre discord:

1:45 - S25 placed between Chopsticks
6:50 - Chopsticks moved to lifting points of S25
8:05 - Aft flaps opened
11:53 - Clear pad PA
12:09 - SQD arm moved away
12:42 - S25 started lifting
14:16 - S25 is placed on top of B9
17:13 - SQD attached to S25

References[]

[1] ttps://twitter.com/SpaceX/status/1659215242617044993

[2] ttps://twitter.com/SpaceX/status/1671927404619767808

[3] ttps://twitter.com/SpaceX/status/1673509777819967488

[4] ttps://twitter.com/SpaceX/status/1673509777819967488

[5] ttps://twitter.com/elonmusk/status/1673580231217618946

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