Booster 18.1 (B18.1) or TT17 is a Block 3 Booster test tank located at Massey's, after undergoing extensive structural and cryogenic testing. B18.1 consists of a forward dome section joined with a common dome, an aft section and additional barrel sections between them. A label was spotted for a B18.1 on Feb 24th 2024, just over a month prior to the spotting of B18.1, leading to the designation of TT17 as B18.1. B18.
B18.1's extensive test campaign served to thoroughly verify the aft section, going through 16 cryogenic and structural load tests over a total of 7 and a half months, concluding on the 15th of January 2026, at which point teams began releasing the tank from the structural test cell.
History[]
Label spotted in Starfactory. c Starship Gazer
Label for B18.1 on a ring stand. c Starship Gazer
On the 24th of February 2025, a label was spotted in Starfactory on a ring stand inside for a "18.1 FWD Ring Flange". According to Starship Gazer, this indicates that B18.1 will "likely be the first test article for Block 2 design Boosters and potentially indicates that Booster 18 will be the first Block 2 design Booster."[2]. The first parts for B18.1 were definitively spotted on April 4th 2025, with a forward dome and barrel section rolling into Mega Bay 1. On April 8th, an aft section was also rolled into Mega Bay 1. However, the header tank of the aft section had previously been spotted on March 26th 2025 [3].
B18.1 was rolled out to the Massey Outpost on May 10th 2025 where it completed its first cryogenic proof test on May 28th 2025, and second lasting roughly 24-27 hours between on June 2nd and 3rd. On August 15th-17th, B18.1 did some more cryo testing.
Timeline[]
- 26 Mars 2025: (Retrospectively) B18.1 header tank spotted
- 4 April 2025: B18.1 Forward dome section and barrel section moved into MB1 and stacked
- 8 April 2025: B18.1 Aft section moved into MB1 and stacked
- 21 April 2025: B18.1 rolls out of MB1 to Starfactory
- 9 May 2025: B18.1 rolled out from Starfactory to Rocket garden
- 10 May 2025: B18.1 rolled to Massey's
- 28 May: 2025 B18.1 cryo
- 2-3 June 2025: B18.1 cryo
- 15 August 2025: B18.1 cryo
- 22 August 2025: B18.1 cryo
- 23 August 2025: B18.1 cryo
- 15 September 2025: B18.1 cryo
- 16 September 2025: B18.1 cryo
- 17 September 2025: B18.1 cryo
- 18 September 2025: B18.1 cryo failure (probable test to failure), but then repaired
- 14 November 2025: B18.1 cryo
- 17 November 2025: B18.1 cryo
- 16 December 2025: B18.1 cryo
Testing Campaign[]
In addition to numerous solely structural load tests the following cryogenic proof tests have been observed:
| Date | Test type | Outcome | Details |
|---|---|---|---|
| 28 May 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 2-3 June 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test with a duration of roughly 24 hours[4], with some counts making it up to 27 hours[5] |
| 15 August 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 22 August 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 23 August 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 15 September 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 16 September 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 17 September 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 18 September 2025 | Cryogenic proof test | Likely Failure | TT17 (B18.1) conducted a cryogenic proof test, which ended in a large amount of venting and was followed up with workers around the vehicle and a 2 month hiatus in testing |
| 14 November 2025 | Cryogenic proof test | Success | TT17 (B18.1) did a cryogenic proof at Massey's. |
| 17 November 2025 | Cryogenic proof test | Success | TT17 (B18.1) did a cryogenic proof at Massey's. |
| 16 December 2025 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 7 January 2026 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 8 January 2026 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
| 15 January 2026 | Cryogenic proof test | Success | TT17 (B18.1) conducted a cryogenic proof test |
02-03 June 2025 - Cryogenic proof test[]
Cryo loading. c LabPadre
Timeline according to LabPadre discord:
- 17:45 Cryo loading underway
- ---
- 20:13 (+1) Detanking underway
15-17 August 2025 - Cryogenic proof testing[]
Cryo testing at Massey
B18.1 completed some more testing. Add timeline here.
- TBD
22 August 2025 - Cryogenic Proof testing[]
B18.1 is currently undergoing testing (as of 7:53 pm, local time)
Gallery[]
References[]
- ↑ https://discord.com/channels/892037187095380008/1126216070349455460/1354625366030946436
- ↑ https://x.com/StarshipGazer/status/1894241866259771570
- ↑ https://discord.com/channels/892037187095380008/1126216070349455460/1354625366030946436
- ↑ https://discord.com/channels/577909263012462594/732227281006755922/1379629222359728189
- ↑ https://discord.com/channels/892037187095380008/1015092682231656529/1379683041437290507