[HammerGS]

What this changes

Planetary ownership now matches the September 2026 SUCS release (version 2026.09.01). It replaces the March 2026 SUCS data.

• 3,174 system files change: owner, administration path and capital, on all 47 SUCS dates from 2271 to 3152.
• The March SUCS events are removed. The new ones are tagged source: SUCS, version: 2026.09.01.
• Hand edits made since March are kept and tagged source: curated (268 events).
• Canon events, population, HPG and planet data are not touched, apart from the Rockwellawan fix below.
• A world with a known owner is never set to Undiscovered. This applies to 1,850 cases.
• Where SUCS only says "Clans", the specific Clans already recorded stay. This covers the Clan Homeworlds and the Pentagon worlds.
• Disputed worlds keep their administration and capital. For example, New Avalon stays a National Capital in 3067.
• From 3138, the Clan Protectorate worlds show the Clan Protectorate as owner.
• Malador Cluster gets its SUCS id (3019), so it now receives SUCS data.
• Saggina is not changed. SUCS gives it code X (Apocryphal), and there is no faction for that yet.
• Rockwellawan now matches its sources: Taurian through 2864, Independent from 2890, New Colony Region from 3059. Two canon events that disagreed are removed.

The new administration paths are displayed by MegaMek/mekhq#10672, which shows each level as an indented row. Neither PR needs the other to merge.

Fixes #648, fixes #643

Source

• Sarna Unified Cartography Kit, version 2026.09.01 (September 2026), Systems sheet.
• Faction codes mapped with the SUCS-MekHQ correspondence table, September 2026.
• Rockwellawan: House Arano, p. 12 (Rimward Periphery map dated 21-07-2890), Second Succession War pp. 78-79 (2864) and The Periphery, 2nd Edition p. 112 (New Colony Region).
• Ten SUCS cells had a stray space and were corrected: Andro, Cammal, Gallitzin, Lee and Monhegan, in 3151 and 3152.

How this was checked

• A separate checker read the SUCS workbook directly. It then loaded every system through MekHQ's own loader and compared owner, administration and capital on all 47 dates. It found no differences.
• The same checker confirmed nothing else in the files changed.
• It also used git to confirm that only events from the March import were removed.
• The checker was tested by planting 18 deliberate errors per run, such as a wrong owner, UND turned into UNDND, a dropped admin level and a misspelled capital. It caught all of them in three separate runs.
• MekHQ universe and validator tests: 1,323 run, 0 failures. Same as on main.
• Rockwellawan was checked through MekHQ's loader on 2851, 2889, 2891, 3023, 3058 and 3060, and matches all 27 years in Sarna's affiliation table.
• validateSystems: 0 errors. Warnings drop from 105 to 51, and none are new. The 54 that went away were the unresolved codes SE and CEI.
• In-game spot checks in MekHQ: 73 systems on 7 campaign start dates (2367, 2766, 3026, 3053, 3068, 3146, 3152), all matching. Each one showed the owner, administration and capital that MekHQ's loader reads from this data. Rockwellawan was also checked in game across its corrected dates.

What is not proven yet

• Saggina keeps its old data until faction X is settled.
• The checker compares owner, administration and capital on each system's primary planet only. Other planets are only checked for unwanted changes.

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• The source is cited above, or this is not a canon change
• The changed entries were loaded in the program and look right - every file loaded through MekHQ's loader and checked against SUCS, and 73 systems checked in game
• Every file in the diff has a deliberate change (no stray reformatting of untouched entries)
• Dev team only: if AI tools were used, the AI Assisted Development label is applied, and I can
  explain and have verified the result