GSE4

GSE4 was the fourth tank that was being built for the orbital launch site tank farm. It appeared to be completed at the end of May. However, after one month of no progress, the GSE tank seemed to be scrapped at the beginning of July. The reason is currently unknown.

In mid August, the GSE4 aft section (dome with a 3-ring sleeve) and the GSE4 fwd section (dome with a 1-ring sleeve) were mated to create a small GSE test tank. On August 25, 2021 the test tank underwent a cryogenic proof test, whose exact purpose and outcome isn't known. According to NSF, the test objective could have been to validate construction methods used for the OLS tank farm.

After some modification work on the test tank in September 2021, GSE4 rolled out to the launch site once again on November 12th (together with B2.1) where it was cryo tested to failure on January 18th.

## Timeline

* 22 Apr 2021: GSE4 section (3-ring stack with dome) moved [aft?]
* 23 Apr 2021: GSE4? aft dome flipped
* 28 Apr 2021: GSE [GSE4 fwd?] dome on sleeving stand, sleeved with 3-ring stack
* 04 May 2021: Fwd dome section attached to crane
* 10 May 2021: Stacking in mid bay [fwd dome section onto other section?]
* 10 May 2021: Aft dome flipped
* 18 May 2021: Aft parts lifted into mid bay [where the rest of GSE is]
* 21 May 2021: According to Marcus House: BN3 stack in high bay is common dome on fwd LOX section (total of 8 rings). GSE4 in mid bay has been stacked this week onto its aft section, now complete
* 02 July 2021: GSE4 fwd dome section scrapped: fwd dome and a single ring has been cut off; remaining 4-ring section attached to crane and moved to scrap yard
* 09 July 2021: Fwd dome outside tent 1 for scrapping [!] [it has been already stacked, but now cut off]
* 17 July 2021: GSE tank aft section (3-ring with dome) moved [~~GSE4~~/GSE6?]; label, likely outdated, mentioning B4: "BN4 aft dome stiffed panel"
* 17 July 2021: Work on a GSE tank inside mid bay (not GSE6? or ~~GSE4?~~), GSE3 fully stacked inside mid bay [?]
* 19 July 2021: GSE fwd dome sleeved (with 2-ring stack) [~~GSE4~~/GSE6?]
* 10 Aug 2021: GSE8 fwd dome stack #2 spotted [GSE8 will replace the scrapped GSE4)
* 19 Aug 2021: GSE4 aft section on a stand (sleeved with dome, 3-ring, with lead-ins)
* 20 Aug 2021: Small GSE tank stacked with GSE4 aft section (3-ring and dome) and GSE4 fwd section (1-ring and dome); purpose unknown
* 23 Aug 2021: GSE4 [test tank?] rolled out to launch site, arrived at 10.23 am
* 23 Aug 2021: **GSE4 test tank [?] rolled out to launch site; towards SoLS Pad A**
* **25 Aug 2021:** **GSE4 test tank cryogenic proof test;** According to NSF, the reason was to validate construction methods used for the OLS tank farm
* 31 Aug 2021: **Rolled back** to production site; to PPS
* 15 Sept 2021: PPS: GSE4 test tank worked on at the top
* 17 Sept 2021: GSE4 work at PPS continued; likely new adapters installed on the top of the dome
* 18 Sept 2021: GSE4 had a smaller grey vertical tank attached to its side
* 20 Sept 2021: Modifications continued
* *11 Nov 2021: BN2.1, GSE4, B2.1 and SN15 shown at PPS; workers prepared concrete forms at PPS near them*
* **12 Nov 2021: B2.1 on structural test stand ("cancrusher", closeup of thrust test setup) and GSE4 moved from PPS to launch site**
* *29 Nov 2021: SPMT moved to SoLS; parts moved to landing pad near GSE4; then went to production site*
* 30 Nov 2021: GSE4 test tank moved southwards on landing pad (Starship Gazer)
* 01 Dec 2021: Moved south
* 05 Jan 2022: Worked on
* 11 Jan 2022: GSE4 test tank worked on
* **18 Jan 2022: GSE4 test tank cryo proof tested to failure (popping)**
* 19 Jan 2022: Remains at launch site
* 20 Jan 2022: Remains still laying around

## 18 January 2022

On January 18th 2022, SpaceX finally tested its GSE4 test tank for a second time after a long waiting period. The tank bursted at 14:34 CT, likely on purpose.

Testing timeline of the Cryogenic Test on 18 January 2022 according to LabPadre [cam time 1 hour off] and NSF streams:

* 10:04 or earlier: Road closed
* 10:31 Pad cleared
* 11:20 Venting of OLS tank farm started
* 11:28 Venting around LOX subcooler area
* 12:12 Venting from GSE4
* 12:17 Frost forming on GSE4
* 13:46 Venting from base of OLIT
* **14:34:14 Tank bursted**
* 15:34 SpaceX employees to pad
* 16:28 Road opened

1. ↑ https://www.youtube.com/watch?v=dGlsuTrvnp4