B2.1

Not to be confused with the booster test tank BN2.1

B2.1 or "booster" test tank 2.1. is a hybrid test tank that consists of a Ship aft dome and a booster forward dome. After being put on the "can crusher," a booster test stand that is capable of testing the outer 20 engines, the test tank was moved to the launch site together with GSE4 on the day of the S20 6-engine static fire.

There's a structure called "top hat" which has been added to this test article. It was connected to the bottom with ropes in order to stress test the structure.

## Timeline

* 20 Apr 2021: B2.1 dome spotted inside tent 1
* 20 July 2021: Aft dome lifted onto sleeving stand [tag ripped off, someone noted B2.1 on it, BN2.1], sleeved with a super heavy aft ring stack, likely to practice dome mating with scrapped parts
* 02 Oct 2021: Booster thrust sleeve (3-ring) with ship thrust puck spotted, unclear use
* 04 Oct 2021: Booster 3-ring fwd section [thought to be B5?] stacked on the booster sleeve with ship thrust puck for unknown reason
* 05 Oct 2021: Mid bay: Hybrid booster-ship tank construction continued; B fwd section and B aft sleeve with S thrust puck
* 13 Oct 2021: Hybrid test tank moved out of mid bay, NSF calls it B2.1 [confusing]
* 15 Oct 2021: B2.1 [?] hybrid test tank still outside mid bay
* 19 Oct 2021: Work through hatch outside mid bay
* 20 Oct 2021: Work continued
* 21 Oct 2021: Work continued
* 22 Oct 2021: Work continued
* 23 Oct 2021: B2.1 (not same as BN2.1) work continued
* 24 Oct 2021: Work continued
* 25 Oct 2021: B2.1: parts added to grid fin cutouts
* 26 Oct 2021: B2.1 test tank work continued
* 28 Oct 2021: Booster test stand has raptor gimbal joints which will attach to B2.1 on each of its RC mounting point
* 28 Oct 2021: **B2.1** moved towards booster test stand at PPS by SPMT, lifted and removed from transport stand, **lowered onto booster test stand**
* 29 Oct 2021: B2.1 work on test stand continued
* 30 Oct 2021: B2.1 work on booster test stand continued
* 31 Oct 2021: Work continued at PPS, work through access hole
* 01 Nov 2021: Preparation work for testing continued at PPS
* 02 Nov 2021: B2.1 testing preparations continued
* 03 Nov 2021: Work continued near gate A3 (NSF confirms the other one to be BN2.1)
* 10 Nov 2021: B2.1 work 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**
* **01 Dec 2021: B2.1 cryo proof test, possibly also puck shucking; the first time OLS tank farm was used for testing**
* **02 Dec 2021: B2.1 cryo proof test**
* **03 Dec 2021: B2.1 Cryo Proof Test**
* 05 Dec 2021: Prepared to move, SPMT moved towards test tank
* 06 Dec 2021: Prepared for rolling back, then **rolled back to production site**
* 07 Dec 2021: B2.1 is **back at PPS**
* 08 Dec 2021: Work at PPS
* 10 Dec 2021: Work continued
* 11 Dec 2021: Work continued at PPS
* 12 Dec 2021: Work continued: strenghtening? ring added around the lower part of the test tank
* 14 Dec 2021: Structural test stand **cap lifted onto B2.1** test tank (the one with the tank like top, has some heavy orange ropes on it, "can crusher cap")
* 15 Dec 2021: Lines installed on the structural test stand (for B2.1)
* 16 Dec 2021: Work continued; **ropes** lowered ("These are likely to be used to pull down the cap while the tank is filled and pressurized")
* 17 Dec 2021: Rocket garden at PPS: B5, BN2.1, B2.1, SN15, B6, SN16
* 17 Dec 2021: Work continued
* 18 Dec 2021: Work continued
* **18 Dec 2021: B2.1 stress tested; Remedios road closed**
* 20 Dec 2021: All ropes connected to hydraulic pistons at the structural test stand
* 21 Dec 2021: B2.1 test tank in structural test stand: closeup
* **07 Jan 2022: Ropes have been detached** from lower attachment points; crews removing one of the ropes
* 08 Jan 2022: Ropes continued to being disconnected from structural test stand
* 11 Jan 2022: Hatch opened by force
* 12 Jan 2022: Test stand cap removed
* 13 Jan 2022: Work through access hole
* 20 Jan 2022: Work on outside
* 25 Jan 2022: Connected to crane for lifting; lifted from structural test stand (lower part of can crusher)
* 08 Feb 2022: B2.1 test tank moved at PPS
* 15 Feb 2022: B2.1 and B6 test tanks, as well as cargo door pathfinder shown
* 16 Feb 2022: B2.1 and BN2.1 next to each other at PPS

## 01 December 2021 - Cryo and Puck Shucker Test

This test was likely a cryo proof test fuelled from the OLS tank farm which was active during the test. The test was conducted after an aborted static fire test on S20 and during a nosecone header tank test on the Ship. It was the first time, both tank farms were simultanously active for a testing purpose.

Timeline according to LabPadre and NSF streams (full day testing timeline on S20 article):

* 15:17 B2.1 "can crusher" slowly getting frosty; top venting started soon after
* 15:25 Venting from ground around B2.1 started
* 15:29 OLS tank farm activity spotted (likely active earlier) at the 2 CH4 heat exchangers/horizontal CH4 tanks [but no CH4 at the farm yet]
* 16:41:12 B2.1 Top vent closed; commentator spotted debris falling off the bottom, indicating thrust pucking test
* 17:21 Frost on B2.1 slowly beginning to disappear; OLS tank farm "ground vent" (south of south berm) spotted (LOX or LN2 overpressurization vent)
* 18:59 Road opened

## 02 December 2021 - Cryo and Puck Shucker Test

Timeline according to LabPadre and NSF streams:

* 09:22 Sheriff at road block
* 13:21 First minor venting at OLS tank farm near CH4 heat exchangers
* 13:25 Pad cleaed
* 13:27 Venting at CH4 heat exchangers spooled up
* 13:49 Venting south of berm began (near the tunnel?) filling began; some venting also visible further east between GSEs and berm (likely from vertical LN2 tank)
* 13:57 CH4 heat exchanger area venting spooled up a lot
* 14:15 Condensation /frost starting to appear
* 14:30 B2.1 top venting slowly beginning
* 14:48 Frost nearly at top, venting has increased
* 14:57 Full frost up to stringers (and a bit further up), top venting continues to increase
* 17:22 Top venting stopped
* 17:25 OLS tank farm venting beginning to decrease
* 17:32 Venting in south region of tf for a few seconds
* 18:00 Two cars to pad
* 18:14:57 Top venting began again
* 18:15 Venting likely from top of GSE bunker or the LN2 vaporizors east of it
* 18:18 Venting south of the berm
* 18:23 Road opened
* 18:31 Vertical LN2 tank venting (near bunker)
* 18:34 B2.1 venting decreased; frost very slowly beginning to disappear

## 03 December 2021 - Cryo Proof Test

Testing Timeline according to NSF and LabPadre streams:

* 5:44 or earlier Road closed
* 6:20 Some OLS tf venting seen from CH4 heat exchangers
* 6:25 Fog
* 9:15 Fog slowly withdrawing
* 9:18 B2.1 spotted, venting a lot from the top and frosty (more venting than on previous days, some venting from the frost)
* 9:25 Tank farm venting as well
* 9:45 Much venting from area aroundof B2.1 (pad lines?); decreased at 9:48
* 9:50 Top venting getting irregular
* 9:51 Short bunker area venting
* 9:51:50 Top venting stopping
* 9:57:05 Top venting for half a minute
* 9:58:03 Short top venting for a few seconds; as well as on 58:42, 59:16, 59:45; 10:00:15, 00:41, 01:11, 01:43 and so on in short intervals until about 10:05; since then only venting from the frost
* 10:00 Venting around the pad area nearly fully disappeared
* 10:05 **Nosecone cage on the move at PPS**
* 10:22 The tank farm vent began again (source not visible, behind B2.1 on Nerdle)
* 10:48:54 Top venting for half a minute
* 11:20 Frost slowly beginning to disappear
* 11:59 Some top venting started
* 12:08 Top venting stopped
* 12:09 Pad venting began agian
* 12:09 Road opened
* 12:17 Top vent started (until 12:22)
* 12:44 Frost fully disappeared; Big horizontal methane tank turned blue
* 12:47 Vertical LN2 tank venting began
* 13:30 Vertical LN2 tank venting nearly fully disappeared