BN3

Booster 3 (BN3 or B3 according to the new naming scheme) was a Super Heavy Booster prototype (first stage). After a short test campaign in July 2021 that concluded with a static fire on July 19th, the uper methane tank was disassembled in August. As of December 2021, the LOX tank section still remained on pad A. Finally, the booster prototype was scrapped in January 2022. It has been referred to by Elon Musk as "Booster 2", later he changed to "Booster 3", mentioning at the same time that this booster will not go orbital with SN20. According to Musk, BN3 or B3 is a "prototype booster" and the next booster would fly to orbit.

Unlike the booster pathfinder BN1, BN3 had its LOX tank at the bottom and the CH4 tank at the top, just as Starship does. This was confirmed by Elon Musk.

## History

As of March 15, no parts had been spotted. However, after BN1 was scrapped and BN2 remained nothing more but some sort of test tank, BN3 stacking and construction began to speed up during May 2021.

According to Chris Bergin, NSF author, SpaceX's goal was to use SN20 and BN3 for a first orbital flight NET August 2021. As of May 27, the booster still was in the high bay for stacking.

On June 25, Musk announced that BN3/B3 won't go to orbit but that it will be tested thoroughly: "We’re almost done with first prototype booster. This will go to test stand A. Next one will fly to orbit. Team has been crushing it many days & nights in a row!" He explicitly confirmed this on June 30: "First one to fly will [have grid fins], so Booster 4. Booster 3 will be used for ground tests. We’re changing much of design from 3 to 4. Booster 3 was very hard to build. Expect especially rapid evolution in first ~10 boosters & first ~30 ships."

In July, booster 3 rolled out and underwent a short test phase which included an ambient, a cryo proof and a static fire test on pad A. The upper methane tank section has been disassembled in August but the LOX section remained on pad A until now (December 2021).

## Timeline

* 28 March 2021: Fwd dome barrel section spotted
* 31 March 2021: Common dome spotted
* 02 Apr 2021: Aft dome (3-ring) barrel section spotted
* 03 Apr 2021: Aft tank #5 ring section (4-ring, with lead ins) spotted
* 23 Apr 2021: BN thrust dome, possibly for BN3 spotted
* 24 Apr 2021: Aft sleeve (3-ring) near the BN3 aft dome (on sleeving stand), later sleeved ["aft dome booster WO# 1626306]
* 25 Apr 2021: Aft section removed form sleeving stand
* 03 May 2021: Aft dome section attached to flipping rig
* 04 May 2021: Aft dome flipped and placed on a cart
* 05 May 2021: Aft dome still attached to flipping jig
* 06 May 2021: Fwd tank #2 section (4-ring) spotted
* 07 May 2021: BN3? common dome flipped (3-ring and dome)
* 14 May 2021: Super heavy booster section moved into high bay for stacking, BN2 or BN3 [vid15]
* 15 May 2021: BN2/BN3 section in high bay rotated
* 16 May 2021: Fwd tank #3 spotted
* 19 May 2021: BN3 in high bay [consensus]
* 19 May 2021: BN3? CH4 assembly spotted, 28 pipes for all 28 enginges "Super Heavy Propellant Manifold", feeding methane to engines from downcomer
* 21 May 2021: Marcus House: Combinations SN20-BN3, SN21-BN4, SN22-BN5, SN23-BN6, then major upgrades for SN24-BN7
* 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.
* 21 May 2021: BN3? fwd dome spotted
* 23 May 2021: Fwd tank #4 booster section spotted
* 23 May 2021: Section lifted in high bay, stacked onto new section
* 25 May 2021: Aft tank #5 section (4-ring, with lead-ins) spotted [see 03 Apr]
* 25 May 2021: BN3 (some 12 rings high) moved in high bay, new stack moved into it and attached to bridge crane, stacking continued; LOX tank now at the bottom according to Elon Musk (unlike BN1)
* 26 May 2021: Stacking continued [?]
* 27 May 2021: Stacked to 16 rings, with common dome on top
* 29 May 2021: Super heavy thrust puck delivered [BN3?], confirming a total number of 29 engines (adding a center engine), which was confirmed by Musk [later to be risen to 32]
* 03 June 2021: Booster Section #5, 4-ring section with lead-ins prepared for stacking
* 04 June 2021: BN3 stacked onto another 4-ring section (now 20 rings tall) [Booster section#5?]
* 14 June 2021: Unknown 3-ring stack with multiple holes and side attachments spotted, later removed from flipping rig and moved; potentially for booster (BN3?)
* 15 June 2021: BN3? fwd dome with attachment pins waiting to be sleeved
* 15 June 2021: BN3 "booster 2" LOX section (20 rings) relocated, then stacked onto aft/engine section
* 16 June 2021: Fwd dome sleeve unhooked and moved into tent 1
* 19 June 2021: Attached to bridge crane
* 19 June 2021: BN3? fwd dome sleeve mounted in the flip rig (which one?); later detached without flipping it
* 19 June 2021: New Superheavy (BN3?) fwd dome sleeve spotted; first sleeve was likely a pathfinder
* 22 June 2021: BN3? fwd dome sleeve moved and sleeved onto the fwd dome on the stand and moved into tent 1; new hot gas thrusters have been added at the top of the sleeve (for Reaction Control System RCS thrusters; "It is beleived these will burn methane and liquid oxygen")
* 22 June 2021: BN3? fwd dome on sleeving stand
* 23 June 2021: BN3/B3 moved slightly in high bay [New naming scheme, B and S insead of BN and SN]
* 24 June 2021: Moved to the left in high bay; CH4 section work began with fwd dome connected to high bay bridge crane
* 25 June 2021: Fwd tank 2 section spotted
* 26 June 2021: Fwd ring section spotted (4-ring stack)
* 26 June 2021: Work on fwd tank section work; the fwd dome spotted earlier this week has been stacked onto other fwd tank section (4-ring); another stack waiting outside
* 27 June 2021: Fwd tank section moved in highbay; work on booster continued
* 29 June 2021: Fwd tank (CH4, 13? rings tall) **stacked** onto lower booster section; now at full height!
* 29 June 2021: Lifted onto transport stand; the section is 23 rings tall (engine section, LOX tank, common dome); some sort of fins have been installed on the engine section; lead ins on the common dome section, prepared for stacking
* 30 June 2021: BN3/B3 work continued, later unhooked from bridge crane
* 30 June 2021: LR11000 began moving towards Pad A, possibly for BN3/B3 lifting
* 01 July 2021: New RCs for July 6 and 7 (7am-5pm) [likely for BN3/B3 testing]
* **01 July 2021: Roll out** (hot gas thrusters haven't been uninstalled, pipes sticking out of lower section side and huge COPV on other side); huge manlift went up to attach the load spreader of LR11000 to the booster; detached form transport stand, **lifted onto Pad A by LR11000** [no engine section???]
* 02 July 2021: Secured on Pad A, still attached to LR11000; work at the base/stand; later, man lifts went up, work on booster through access holes
* 04 July 2021: Long tube moved to BN3/B3 at launch site (possibly a part of its raceway)
* 04 July 2021: Work continued, still attached to LR11000
* 05 July 2021: Loadspreader and LR11000 detached from BN3/ B3 at 8:42 am
* 05 July 2021: Test preparations work continued with lots of wires and some piping installed; ventilation hoses run into booster
* 06 July 2021: Work preparation work continued
* 06 July 2021: New RC [BN3/B3] for Thursday, July 8 (12-8pm); Friday, July 9 (6am-8pm); Monday, July 12 (12-8pm)
* 07 July 2021: Work continued through the night
* 08 July 2021: BN3/B3 venting early in the morning [thrusters or pressure?]
* 08 July 2021: Work continued with several man lifts up ahead of testing
* **08 July 2021: Ambient pressure test**
* 09 July 2021: Work continued with several man lifts up and work through access holes
* 10 July 2021: Work continued
* 10 July 2021: RC57 delivered to launch site at 6:55pm; installation on BN3/B3 began on 10:13pm
* 11 July 2021: Installation of first engine on BN3 continued (RC57) [Raptor Center]
* 11 July 2021: Second raptor engine for BN3/B3delivered to launch site at 12:52 pm, unknown RSN
* 12 July 2021: Second BN3/B3 raptor, identified as RC59, lifted on 12:10 am local; but moved back to build site later
* 12 July 2021: Work continued
* **12 July 2021: Cryo proof test**
* 12 July 2021: Second Raptor delivered to BN3/B3 at 11:36 pm
* 13 July 2021: Second raptor delivered to launch site (BN3/B3) at 2:28 am
* 15 July 2021: Work continued
* 18 July 2021: Alert notice for July 19 for Static Fire attempt on BN3/B3 issued (12-10pm)
* **19 July 2021: BN3/B3 static fire**
* 20 July 2021: Work continued (inspection of raptors and aft section)
* 21 July 2021: Lower LOX tank hatch closed
* 22 July 2021: Top dome venting; work at the engine section; RC59 removed, packed and transported back to the build site
* 22 July 2021: RC57 removed from BN3/B3 at 11:54pm
* 23 July 2021: RC62 removed from BN3/B3 at 2:22 pm, moved to build site
* 27 July 2021: Raptor engines delivered to build site (likely those earlier removed from BN3/B3)
* 27 July 2021: GSE pipes for fuelling disconnected
* 01 Aug 2021: Still on pad A, plans unclear
* 14 Aug 2021: Attached to LR1100 with spreader bar
* 14 Aug 2021: BN3/B3 began to be **scrapped**; cut in half; upper segment lowered
* 15 Aug 2021: Scrapping continued; CH4 tank further cut into parts
* 16 Aug 2021: LOX tank attached to LR11000 for further scrapping
* 17 Aug 2021: Dismantling work continued
* 18 Aug 2021: LOX tank still on pad A
* [nothing happened]
* 07 Jan 2022: LR11000X moved towards B3 and attached to it [vid 08]
* 07 Jan 2022: B3 attached to LR11000X at 8:53pm
* 08 Jan 2022: B3 LOX section **scrapping** began on pad A; tank section cut off from aft section an lifted away; scrapping of tank section continued
* 09 Jan 2022: Scrapping continued
* 10 Jan 2022: Scrapping continued
* 11 Jan 2022: Scrapping continued
* 12 Jan 2022: Scrapping continued
* 13 Jan 2022: B3 engine section removed from Pad A
* 25 Jan 2022: Remains cut into smaller sections
* 31 Jan 2022: Some remnants still lying around
* 03 Feb 2022: Methane manifold lying around at launch site

## 08 July 2021 - Ambient pressure testing

Timeline according to LabPadre streams (nerdle cam time):

* 17:47 or earlier: Road closed
* 18:20 Pad clear
* 19:26 Ground vent until 19:29
* 19:52 B3 venting [?]
* 19:56 Road opened, cars to pad
* 20:00 Tank farm venting (3 vents)
* 20:42 One tank farm vent stopped
* 21:11 Black vertical tank vent stopped
* 22:12 Man lift up
* 22:20 Vents or something at BN3 base while man lift up
* 00:14 New tank farm vent
* 00:18 Other tank farm vent stopped
* 03:01 New tank farm vent until 03:38 (now 2 vents)
* 04:53 Vertical tank vent started again
* 05:08 Both remaining farm vents stopped
* Work on booster continued through the night

## 12 July 2021 - Cryo proof testing

Timeline according to LabPadre and NSF streams:

* 13:17 Road seems to be closed behind Cryo tank shell #2 after it passed the closure point
* 15:14 or earlier: Sheriff at road closure (soft closure)
* 16:19 Pad cleared
* 16:28 Ground vent
* 16:45 Venting from skirt/stand, puffs
* 16:58 Loud venting noise every few minutes; later located at the booster fwd dome area
* 17:05 One vent visible from a little venting pipe at the raptor engine
* 17:18 Tank farm activity
* 17:32 Long (30+secs) venting from common dome area (on two sides) as well as continuous on and off of the top fwd dome vents (also on both sides); both vents continued with short venting intervals in next minutes
* 17:37 CH4 tank (upper) frost appearing
* 17:38 Huge venting from area around pad (inciated by fast vent from pad center; unclear if from booster or from fuel lines)
* 17:39 Venting from around the raptor increased
* 17:43 Huge skirt venting again [like at 17:39]
* 17:47; 17:49; 17:52; 17:54? Huge pad venting again
* 17:50; 17:52; 17:55 Huge fast venting from the right skirt area (NSF stream)
* 17:54 Fast downward vent
* 17:55 Frost isn't increasing anymore; starting to decrease
* 18:02-18:07 Long cmn and fwd dome area vents - depress? [cmn dome: tri-vent; fwd dome: bi-vent]
* 18:07 Pad vent [far south east] for several minutes; increased at 18:11
* 18:12 Some frost/condensation at the bottom of LOX tank
* 18:24 Frost nearly fully disappeared; no more booster venting
* 18:35 Road opened; some tank farm activity still going on
* 18:41; 18:46; 18:50 Small cmn dome final depress vents
* Small vents continued

## 19 July 2021 - Static Fire

Elon Musk confirmed a "Full test duration firing of 3 Raptors on Super Heavy Booster!" after the static fire.

Timeline according to different sources (LabPadre and NSF); times: Usually Nerdle cam (NC), Launch pad cam is 2 min earlier (LP):

* 14:36 Sheriff at road closure point
* 14:47 Some sheriff car to pad/beach?
* 15:54 Transport of something from Launch site to build site
* 15:59 Ground vent (5 min)
* 16:15/16 Pad clear
* 17:33 Ground vent (short); 17:43, 17:50, 18:06 as well
* 18:20 Recondenser first puffs
* 18:28 Recondenser (18:28:55 NC, 27:14 LP)
* 18:29 Ground vent, now bigger (29:50 NC)
* 18:30 Farm vent (30:11 NC, 28:57 LP)
* 18:37:19 Small B3 skirt vents (LP), together with venting from external fuel line (fuelling)
* 18:37:42 Side vent from upper adapter area (LP)
* 18:38:54 Cmn dome vent (NC), also 18:39:30, 18:40
* 18:39 Skirt venting increased
* 18:41:58 Venting from bottom of Pad A (NC)
* 18:42, 43, 44, 45, 47 Fwd dome vents (barely visible, sound delay, NC)
* 18:42 Stand vent (LP)
* 18:45:30 More stand vents (left raptor chill vent starting from original stand ring?), skirt now full of venting (LP)
* 18:46:00 Venting around stand, skirt area increased a lot, possibly Raptor Chill
* 18:50:45 Venting increased a lot [raptro chill vent?] (LP)
* 18:45 Siren
* 19:06 Static fire (19:05:58-06:01 NC with some after burn; 04:42-4:45 LP), with cmn dome vent succeeding right after
* 19:05:30 Skirt venting appeared again, as well as from left stand area
* 19:32 Detank
* 19:36 Huge adapter vent
* 20:59 Road opened

## References

1. ↑ https://twitter.com/elonmusk/status/1408245758869086209
2. ↑ https://twitter.com/elonmusk/status/1397348226806665220
3. ↑ https://www.nasaspaceflight.com/2021/03/starship-sn11-spacex-orbital-flight-summer/#more-76751
4. ↑ https://twitter.com/elonmusk/status/1408245758869086209
5. ↑ https://twitter.com/elonmusk/status/1410327121432657929
6. ↑ https://www.youtube.com/watch?v=U\_fsMd9xCCQ
7. ↑ https://www.youtube.com/watch?v=N0sKS0Ea8xs&t=107s
8. ↑ https://twitter.com/elonmusk/status/1417274819461095432