China's Space Program News Thread
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by78
General
The current CZ-7A (GTO 6.6t) will be gone for sure as CZ-7B gives 7.2t as the slide also said "change/upgrade CZ-7A to two stage rocket". So it sounds to me that they won't keep CZ-7A in its current form at least, or drop it all together.
There was a 3 stage upgrade of CZ-7A by changing the 1st stage with YF-100K and 2nd stage with one YF-100M and 3rd stage with one YF-75D. The upgrade will give 8.2t in GTO, higher than CZ-7B's 7.2t. The minimum GTO requirement is 7t. So there seems to be no need for this upgraded 7A. But the drawback of 7B,CD are the enlarged 1st stage which was a concern of 4 landing sites for 1 stage and boosters and transportation on railway. The upgraded 3 stage option was favoured in the study, so we never know.
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I do not think railway transportation will be a major issue since most launches are changing to Hainan island.
Deliveries to Hainan island are via ship.
But the CZ-7A design might still be kept as a replacement for CZ-2 family on Chinese inland launch sites for security purposes.
There have long been complaints about the toxic fuel in CZ-2 in inland sites where dropped stages end up near inhabited places.
Deliveries to Hainan island are via ship.
But the CZ-7A design might still be kept as a replacement for CZ-2 family on Chinese inland launch sites for security purposes.
There have long been complaints about the toxic fuel in CZ-2 in inland sites where dropped stages end up near inhabited places.
The launch site requirement is Xichang + 7t GTO. This is the minimum requirement for strategic (military) purpose. So the 3.35m diameter is still there.
Remember, China will never rely on Wenchang, Xi Jinping has repeatedly emphasized 底线思维 (bottom line). Everything must have a minimum performance in case of war, even if that means the overall performance is not the best. That is why China insists on 3.35m max diameter instead of doing something like the Americans (whatever suits the best performance).
I think there will be a natural split between civilian and military moving forwards, with Wenchang hosting the heavy lift and commercial launches. The solid fueled CZ-11 can be used for rapid (military) response and can be launched at sea or almost anywhere the CZ-6/6a out of Taiyuan is available for heavier SSO launches. The other 2 inland sites don't seem to have LOX facilities fitted yet so they seem to be in no hurry to retire the CZ-2,3 and 4s
escobar
Brigadier
We are talking about GTO payload, your examples are all SSO except CZ-5's 14t GTO which is for Wenchang. Otherwise, all GTOs must be possible to be launched from Xichang even if they can be launched from Wenchang.
The split has nothing to do with strategic bottom line. In the near future, at time of war, Wenchang is calculated as lost, Xichang is the only one left.
Taiyuan already supports LOX such as CZ-6 and 6A's. If they put the demand of CZ-7 GTO variants from Xichang, Xichang will be upgraded to support LOX.
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SSO is the most useful orbit type for most military recon payloads. Military GTO launches are mainly for communication and relay work. We can debate which category will need to replaced first/most urgently when a shooting war starts!
As I said Taiyuan supports LOX and is used primarily for SSO launches but the other 2 don't as yet, so your assertion of a strategic bottom line of GTO payloads wrt Xichang is either presently catered for by existing CZ 3 rockets or not considered a current or that imminent a requirement for the newer KeroLox launchers otherwise the facilities at Xichange would have been upgraded with LOX facilities already/first. Not hypothesizing Just going with the facts as they stand!
Anyway for military use a UDMH/N2O4 launcher is arguably superior to Kerolox since its easier to store and handle in sub optimal operating i.e. war time conditions but the toxic nature of the fuels and lower efficiency less ideal for other uses.
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