Shepherd Economics refers to the situation that shepherd boys only graze when grazing, regardless of the damage to the grassland
The excreta of passengers in the spacecraft is treated and purified into oxygen, water and salt, which are recycled and then used by passengers
 In economics, in order to pursue high production (consumption of natural resources) and high consumption (transformation of commodities into pollutants), they consume a large number of natural resources quickly and choose waste accumulated environmental pollution