Promise Ledger
Japan Aerospace Exploration Agency. These are the dated public commitments by JAXA and its people that we could source to a primary, with what happened.
5 entries: 2 met; 1 met late; 2 revised.
Plain counts, not a grade or a ranking. A short record is not a complete one. Updated Sep 28, 2026; each entry shows the date it was last checked against its source; scoring rules on the methodology page.
This first release is a selection, and a short record is not a complete record. Each programme milestone enters the ledger at its earliest dated public commitment we can find in a primary source, for governments and companies alike. Later dated commitments for the same milestone are shown on that one entry as a revision chain, oldest first, rather than as separate entries.
Revised · worded as a target
First flight · JAXA
“平成32年（2020年）に試験機１号機を打ち上げる計画。”Translation: “The plan is to launch test flight No. 1 in Heisei 32 (2020).”
Said . Source: JAXA: 新型基幹ロケットの開発について (Dec 24, 2013, page 7 (4. development plan))
Context: JAXA report "新型基幹ロケットの開発について" by Executive Director Mamoru Endo to the MEXT Space Development and Utilization Committee (13th meeting), published as a JAXA press item on 2013-12-24. The vehicle was named H3 in July 2015.
Later dated commitments for the same milestone
The counts use the original commitment. The latest date in the chain stands as: met.
Outcome: H3 test flight No.1 lifted off on 7 March 2023; the second stage engine did not ignite and the vehicle was destroyed by command. (, on or before the latest deadline)
Outcome source: JAXA: Launch Failure of H3 Launch Vehicle test flight No.1 and Setting up a Special Task Force (Mar 7, 2023)
Checked against the source on Sep 26, 2026. Report a correction or send a response to this entry ·
Met late · worded as a commitment
Launch · JAXA
“JAXA has decided to postpone ... that of the second test flight from JFY 2021 to JFY 2022.”
Said . Source: JAXA: Change of Schedule for the H3 Launch Vehicle Project (Sep 11, 2020, paragraph 1)
Context: The same release records the earlier plan for test flight No.2 in JFY2021, which appears only as a schedule chart in JAXA’s 2018-11-29 report (page 6); no dated sentence commitment for JFY2021 was found.
Outcome: H3 test flight No.2 launched on 2024-02-17 and its second stage reached the planned orbit. No dated JAXA statement moving it out of JFY2022 before 31 March 2023 was found. (, 323 days after the deadline)
Outcome source: JAXA: Launch Result of H3 Launch Vehicle test flight No.2 (Feb 17, 2024)
Checked against the source on Sep 26, 2026. Report a correction or send a response to this entry ·
Met · worded as a commitment
Landing · JAXA
“it will now be conducted as follows: January 20, 2024 (Saturday) ... About 12:20 am (JST) Landing on the lunar surface”
Said . Source: JAXA: Moon Landing of the Smart Lander for Investigating Moon (SLIM) (Dec 5, 2023, paragraph 1 and schedule list)
Context: 'It' is the SLIM lunar surface landing, earlier scheduled for January or February 2024. JAXA named a fallback opportunity around 16 February 2024.
Outcome: SLIM landed at 0:20 am JST on 20 January 2024 (19 January UTC) about 55 m from its target and communicated with Earth; after losing thrust on one main engine at about 50 m altitude it came to rest in an unplanned attitude with its solar cells not generating power at first. (, on or before the deadline)
Outcome source: JAXA: Outcome for the Smart Lander for Investigating Moon (SLIM)'s Moon Landing (Jan 25, 2024)
Checked against the source on Sep 26, 2026. Report a correction or send a response to this entry ·
Revised · worded as a target
Launch · JAXA
“2024年度の打上げをターゲットに検討を進めている。”Translation: “Studies are proceeding with a target of launch in fiscal year 2024.”
Said . Source: JAXA: 宇宙科学ミッション（MMX・DESTINY＋・JUICE）の検討状況について (Jun 14, 2018, page 11 (2.2 MMX mission overview))
Context: JAXA report to the MEXT Space Development and Utilization Committee (42nd meeting), published as a JAXA press item on 2018-06-14. The same report cites the government roadmap of 12 December 2017 aiming for launch in FY Heisei 36 (2024).
Later dated commitments for the same milestone
The counts use the original commitment. The latest date in the chain stands as: came due, not met (awaiting confirmation).
Outcome: Not yet launched as of 2026-09-26; the window has not opened.
Outcome source: JAXA: Launch schedule of the Martian Moons eXploration (MMX) spacecraft aboard H3 Launch Vehicle flight No.10 (H3 F10) (Aug 20, 2026)
Checked against the source on Sep 26, 2026. Report a correction or send a response to this entry ·
Met · worded as a commitment
Launch · JAXA
“Launch date : October 21, 2025 ... Reserved launch period : October 22 through November 30, 2025”
Said . Source: JAXA: Launch Schedule of New unmanned cargo transfer spacecraft1 (HTV-X1) aboard H3 Launch Vehicle flight No.7 (Aug 22, 2025, schedule table)
Context: Launch schedule table in JAXA's announcement for the new unmanned cargo transfer spacecraft HTV-X1 aboard H3 flight No.7.
Outcome: After a weather postponement from 21 October, H3 flight No.7 lifted off at 9:00:15 am JST on 26 October 2025 and HTV-X1 separated about 14 minutes later. (, on or before the deadline)
Outcome source: JAXA: Launch Result of New unmanned cargo transfer spacecraft1 (HTV-X1) aboard H3 Launch Vehicle flight No.7 (Oct 26, 2025)
Checked against the source on Sep 26, 2026. Report a correction or send a response to this entry ·
Open data: download the whole ledger (CSV, CC BY 4.0). Archived on Zenodo, DOI 10.5281/zenodo.22985970. How entries are scored: methodology. No sponsor, advertiser or partner can add, remove, reorder, annotate or preview an entry, and these pages carry no advertising.
Cite as: SpaceNexus. (2026). SpaceNexus Promise Ledger (Version 2026-09-28) [Data set]. https://doi.org/10.5281/zenodo.22985970. Licensed CC BY 4.0.
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