Considering how easily amateur space watchers have been able to track "secret" USAF space missions, it would be near impossible to hide an orbital nuke system, also anything in orbit follows very predictable tracks. If you want your orbital nuke to be able to hold every possible target at risk, it would have to be placed into a polar orbit which really limits your options for when a specific target can actually be hit. Of course you could put a lot of them into orbit, but that is a whole other can of worms.
Nothing China is doing will comes as a surprise, the intelligence community is quite aware of their efforts. Now if people are paying attention to their reports, well that is a different question. But China does not have the advanced early warning systems that the US and the Soviet Union had. You don't need a depressed trajectory to hit China. A Trident launch from the Indian Ocean or ALCMs from the Middle East could do the trick just as easily. Not that the US would actually do something like that, but they have sailed SSGNs right off the coast of China. Heck, you could even pull off a Soviet style "Bastion" in the Sea of Japan.
Nothing China is doing will comes as a surprise, the intelligence community is quite aware of their efforts. Now if people are paying attention to their reports, well that is a different question. But China does not have the advanced early warning systems that the US and the Soviet Union had. You don't need a depressed trajectory to hit China. A Trident launch from the Indian Ocean or ALCMs from the Middle East could do the trick just as easily. Not that the US would actually do something like that, but they have sailed SSGNs right off the coast of China. Heck, you could even pull off a Soviet style "Bastion" in the Sea of Japan.