20-30mT and 5m aren’t onerous restrictions.

The power of positive thinking, eh?

Straw man, the reactor would be launched in one piece.

How do you figure?

They would dock modules, refuel tanks and move and install equipment racks inside pressurised habitats.

An interesting way to build a skyscraper, and uniquely lacking in explanation. How do you “dock” modules of a skyscraper? Why would you refuel it in the first place? And why are you rambling about furnishing the thing?

20-30mT and 5m aren’t onerous restrictions.

Astronauts playing Legos isn’t anywhere near the league of building a nuclear reactor in space.

Straw man, the reactor would be launched in one piece.

How do you inflate a nuclear reactor?

You don’t have to.

Oh, so when your containerized skyscaper material and manpower arrive on site, they assemble them using good old brawn and hand tools?

They would dock modules, refuel tanks and move and install equipment racks inside pressurised habitats.

Especially as it is difficult even with terrestrial logistics and infrastructure. Trucks, roads, railroads, aircraft, shipping containers, vacuum facilities etc all impose size constraints.

Oh, so when your containerized skyscaper material and manpower arrive on site, they assemble them using good old brawn and hand tools? Pay no attention to that factory over yonder.

Why couldn’t they? Skyscrapers are built using existing tractor-trailer transportation, and the ISS has shown we can build very large modular structures within a 50,000 lb & 5m wide limit.

Yes, let’s compare a 1000 ton, flimsy toy to a 300,000 ton skyscraper–or a 100,000 ton seagoing ship. Maybe an apple tree, since not a one has to do with any of the others.

And that’s without using inflatables, which allows for even larger diameter structures using existing launch vehicles.

How do you inflate a nuclear reactor?

This all gets back to need. Where are the requirements for something beyond what we can do today?

What do you think we can do today?

And while we are on ISS, every module could have been carried into orbit on an EELV as far as MASS is concerned. SLS is nothing more than a jobs program.

Congrats. It’s good to know Americans could’ve cut $25-30 billion off the price tag for putting together the most useless scenic lookout on or off Earth.

Prez, With all the experience with ISS construction?

What experience? ISS failed to even spark a revolution in industrial and construction processes dirt side. What you have a series of one shots designed overwhelmingly to achieve one goal–to fit on the Shuttle. Would you fly iSS to the Moon? To Mars? To Saturn? Hell, would you even reboost it if you could get away with leaving it in freefall?

Astronauts playing Legos isn’t anywhere near the league of building a nuclear reactor in space. And a vestigial capability to take on hypergolic propellant doesn’t even play the same sport as replenishing cislunar and interplanetary spacecraft.

When it’s time to head on to Mars, the vehicle will have to be assembled in orbit prior to departure. Not to mention sending some things on ahead (like surface hab(s), power source, surface rovers).

Undoubtedly (though I don’t give a damn about going to Mars). So either all your complete assemblies are going to be 20 mT and 5 meters in diameter, you’re going to build a real industrial capability in orbit, or you’re going to need a bigger rocket.

Mere docking and refueling should be most of the “assembly” work.

Provided your payload can stay under your arbitrary mass and faring restrictions.

Especially as it is difficult even with terrestrial logistics and infrastructure. Trucks, roads, railroads, aircraft, shipping containers, vacuum facilities etc all impose size constraints.