H3 Development Update thread

[FutureSpaceTourist]

[catdlr]

The H3 Rocket: Flight After Failure - Documentary 360

Restriction to viewing on YouTube Only.

https://youtube.com/watch?v=urcXcdxJyJk

Aug 11, 2024
Japan’s aerospace aspirations encountered a significant setback when their latest large rocket failed to launch. This is the year-long journey of a crew determined to reach for the stars.

[catdlr]

Ground burning test of SRB-3
https://youtube.com/watch?v=MMx-mGbLKN0

Ground burning test of solid rocket booster (SRB-3)certified motor for H3 rocket
(Including gimbaling test for epsilon rocket 1st stage)

2020/2/29 (sat)
3 minutes between 11:00 - 19:00 (+0900 JST)
TNSC(TaNegashima Space Center)


https://youtube.com/watch?v=RJitR86EKBs

Yet another view of this test from 2-29-2020

[Fuji]

H-3 project will be updated for launch turn around time improvement up to 1 month. 
Up to 6 launch per year to more than 7 launch per year at JFY 2028.
VAB improvements and to be expanded ground LOX tanks.
https://www.yomiuri.co.jp/science/20241221-OYT1T50050/
https://www.mext.go.jp/content/20241225-mxt_uchukai01-000039378_4.pdf

[catdlr]

Space Intelligence
@SpaceIntel101
LE-9 Engine Combustion Test🔥at the Tanegashima 🇯🇵 Space Center🚀✨
This veteran test stand has over 100 LE-9 engine tests under its belt!💪🏽
Japan's H3 is powered by 2 or 3 LE-9, depending on the used configuration.
It uses a highly reliable expander bleed cycle generating 1,471 kN (331,000 lbf) of thrust.

https://twitter.com/SpaceIntel101/status/1958452532889473322

[AndrewM]

https://www.japantimes.co.jp/news/2025/08/23/japan/science-health/japan-new-iss-resupply-vehicle/ [Aug. 23]

Kounotori was launched on an H-2B rocket, an enhanced version of the H-2A rocket, due to its heavier weight compared with regular satellites. For the seventh H3 rocket, the number of solid rocket boosters (SRB) will increase to four from two used in the first to fifth H3 rockets.

In addition, JAXA plans to launch the sixth H3 rocket without SRBs by March 2026.

I believe the mention of sixth and seventh is swapped here as sixth flight is HTV-X1 on a H3-24L with the seventh flight being the H3-30 Test Flight. Looks like that flight is now Q1 2026.

[Galactic Penguin SST]

https://www.japantimes.co.jp/news/2025/08/23/japan/science-health/japan-new-iss-resupply-vehicle/ [Aug. 23]

Kounotori was launched on an H-2B rocket, an enhanced version of the H-2A rocket, due to its heavier weight compared with regular satellites. For the seventh H3 rocket, the number of solid rocket boosters (SRB) will increase to four from two used in the first to fifth H3 rockets.

In addition, JAXA plans to launch the sixth H3 rocket without SRBs by March 2026.

I believe the mention of sixth and seventh is swapped here as sixth flight is HTV-X1 on a H3-24L with the seventh flight being the H3-30 Test Flight. Looks like that flight is now Q1 2026.

These two launches still keep their original mission numbers, i.e H3-F7 with HTV-X1 will now fly before H3-F6 (the -30 one) with VEP-5.

[AndrewM]

Looks like H3s flight rate will be increasing beyond the initial target according to Nobuyuki Shiina at the World Space Business Week conference.

Launch companies double down on increasing flight rates despite setbacks [Sep. 15]

He said demand is prompting MHI to increase launch rates for its H3 rocket. “The original plan was launching six launches per year,” he said, but is now projecting growth. “Not drastically, but year by year: six launches, seven launches, eight launches.”