What are the plans for space immigrants?

From 65438 to 0977, Dr. O 'Neill of Princeton University conceived to build a huge space immigrant island in space within the gravity of the earth and the moon, and became the second hometown of human immigrants. This kind of cosmic island rotates at a certain speed in space, producing centripetal force to simulate the gravity of the earth. The cultivated soil on the island, together with the incident sunlight, forms an artificial ecosystem. The activities on the island of the universe rely on solar energy, and make full use of weightlessness and sunlight to establish a cosmic industry, which has become the foundation of a cosmic city. The US government spoke highly of this idea and allocated special funds to support research.

O 'Neill designed three models of the universe island based on the earth:

(1) Island is a hollow sphere with a diameter of 512m. Inside the equator on the island is a residential area. Large-area glass windows are installed in high latitudes, and sunlight is collected by mirrors outside the sphere. Grain is produced by agricultural areas outside the island, and industrial raw materials are supplied by minerals on the moon. The shielding layer of the island is 2 meters thick. The total weight of soil and buildings on the island is 6,543,800 tons, and the protective layer weighs 30,000 tons.

(2) The island is a sphere with a diameter of 3600 meters.

(3) The island is a hemispherical closed cylinder, with a diameter of 6.4 kilometers and a length of 32 kilometers, with a land area of 270 square kilometers, which is equivalent to a big city.

These cosmic islands are more complex and advanced than each other, can accept more and more immigrants and eventually become a space city. To build a space island, we must solve the problem of material transportation, that is, there must be a special means of transportation, that is, spacecraft. It's like an ordinary plane that can be reused. After the space flight, it can spread its wings and glide back to the earth, and then fly in space after two weeks' rest. Space contact spacecraft will transport cylindrical capsules into space one by one, assemble them into space stations, and then build space islands on this basis.