The mean diameter of Psyche is about 180 to 200 km, with a mass of 2.3 x 1019 kg, or 23,000,000 billion metric tonnes. That’s a lot of iron.
The International Space Station has a mass of 419,455. Most of the station was built during the time that costs were greater than $20,000 per kg. If we were to rebuild the station, using the expected costs of the Falcon Heavy rocket, the costs of launching the material would be just under one billion dollars. But suppose we wanted to build something big? Let's take a large cruise ship, capable of carrying 1000 passengers, as an example. The Crystal Serenity has a mass of 68,870 gross tons, or 62.6 million kilograms. The cost to launch the material to rebuild the Serenity in orbit would be about 138 billion dollars. Just think how much cheaper and easier it would be if the material to build things was already in space!
You would need a lot of conductive metal, and a magnetic core….
Science Fiction Inspiration
Neal Stephenson, 2015, SevenEves, 880p.
Stephenson's plot involves survivors of global disaster building a sustaining colony in a metallic planetary core.
Robert Heinlein, 1966, The Moon is a Harsh Mistress, 382p.
Heinlein uses magnetic accelerators to launch cargo capsules from the Moon to the Earth.
Harold Goodwin, 1952, Rip Foster Rides the Grey Planet, 250p.
A cold-war youth novel about international struggle for control of a unique asteroid made of Thorium.