America should already be developing it, and in another couple of years, they will likely launch a couple at Japan.
But, given Hua Country's current conditions—
Nuclear technology shouldn't be a problem; He Tiantian can always learn what she doesn't understand in the Virtual Learning Space.
If push comes to shove, she could also make purchases at the Dian Niang Mall.
However, the various industries involved in the whole project, other technical requirements, and the many raw materials needed, that's going to be the real headache.
Even the new Hua Country had to mobilize the entire nation's strength just to produce Miss Qiu.
And now, with Hua Country's people living in hardship and the country's industry almost non-existent, He Tiantian, no matter how capable, couldn't even produce a single Mushroom Egg.
"Forget it, let's start with a more attainable goal, build an arms factory, and produce some machine guns, cannons, and such."