>>MrZand+(OP)
It is, unless you take Musk's hype about Starship as fact. With rockets that are actually potentially available the best price is $1500/kg to LEO, so either they're presuming the whole setup weighs in at 3-4 tons (which is less than the shielding alone) or that they can get it launched for a few orders of magnitude less than what's on the market now (and they do say they assume $30/kg).