Please clarify whether I have understood correctly that there are:
- a 12A version with 7 engines;
- a 12A version with 9 engines and a different stage diameter?
And there is also the 12B, but that is something entirely different...
yes, the original plan for 12A from 2021-2022 was to put 9 Longyun engines in a 3.8m stage derived from the CZ-12's, using the same tooling, with a backup of 7 engines if that turned out to be impossible (resulting in 3t to SSO instead of 6t), ultimately SAST and JZYJ couldn't fit 9 and had to go for the backup option.
More recently SAST and JZYJ have designed a variant that could use 9 (uprated, 80tf) Longyun engines, but in a 4.2m diameter launcher, enabling performances of 13t to SSO, but this would require different tooling and significant development work, although it should still be compatible with existing ground infrastructure at Wenchang*, Jiuquan and soon Haiyang.
The development of the CZ-12B was started in the 2nd half of 2024 because of the low performances of the CZ-12A, the poor prospects of evolution of the CZ-12A (even this improved, 9 engines CZ-12A would be less powerful than the CZ-12B, which can lift 15t to SSO), and parochial interest from CASC-AALPT which didn't appreciate losing its monopoly on CASC launcher's propulsion. The development was put under the responsibility of the CASC Commercial Rocket Company (CACL), a new high level subsidiary which was mainly staffed and directed by SAST employees, but still ultimately under the responsibility and majority ownership of CASC proper, instead of answering to SAST, and with increased participation from CALT and AALPT.
This decision and change of focus slowed down the development of CZ-12A, from which ressources was pulled, and when CZ-12B was announced in November 2024, there were even rumors that only a single CZ-12A would be produced, eventually we did learn that JZYJ had
two sets of engines, and that the initial first stage meant for suborbital test was repurposed for orbital launch, so we know there should be at least a 2nd CZ-12A launch probably in mid-2026. Meanwhile the CZ-12B was widely advertised, even abroad through CGWIC, for example at the Paris air show in June.
The latest rumors have been more encouraging for the CZ-12A program and it is said that
some kind of further production has been approved, the exact details are unknown and it isn't certain if SAST will find the funding and manpower to and decide to undertake the full development of the larger variant of the CZ-12A, it may be possible that they will keep iterating on the CZ-12A to have their own operational RLV (CZ-12 and 12A still seem under the SAST responsibility and not CACL's), and complement their launch capability, it may also be possible that they will focus on furthering their roadmap that they announced 3 years ago,
China's Space Program Thread II and undertake the development of a larger RLV.
As an aside: another fun rumor is that a title of Academician of the Chinese Academy of Sciences had been in play for the program manager of the CZ-12A if they could land it this year, not sure if he can get it now!
*It's not sure if CZ-12A will ever launch in Wenchang now, that was considered when it was seemingly the fastest way to get it to the pad but it turned out that building a new launch complex at Jiuquan was faster than adapting an already existing one... And the fees that HICAL c (which is jointly owned by the provincial government, CALT, CASIC and CSCN) charges (minimum $5M/launch, more than 3 times the equivalent at Cape Canaveral) seem to deter most commercial customers, at least outside of Governmental CSCN Guowang launch contracts, with the recent news that CALT seems to be trying to get exclusive use of the 2 new launch sites at HICAL to launch 75+ times a year, it's possible SAST won't bother with the launch sites outside of current CZ-12 Guowang launches.
