The MIT Tech Review reviews several authors making the case against human space colonization, highlighting doubts about the practical feasibility of off-Earth communities, who will bear the exorbitant costs and who will profit, and the harsh environment of space and its effect on the human body. But the ambition of more regular human space travel is already having impacts today that are being externalized to people, the environment, and other industries. 

SpaceX’s Starship dwarfs other rockets and requires more than a million gallons of super-cold liquid methane and liquid oxygen propellants. With the company’s ambitions of daily launches or more, the number of tanker trucks traveling from distant refineries to deliver the propellants takes time, emits pollution, and clogs roadways. SpaceX’s solution is to build its own plants to generate the cryogenic fluids, which would require building on emergent wetlands and wind-tidal flats near their facilities. Residual nitrogen, oxygen, and argon gases would be vented back into the atmosphere. 

Environmental groups say SpaceX has shown little concern for the wildlife surrounding its projects and has ignored environmental regulations, including by discharging tens of thousands of gallons of industrial wastewater into the surrounding environment in violation of the Clean Water Act. These groups have filed a lawsuit against the company demanding an extensive environmental review of Starship launches. 

Rockets also inject soot directly into the upper atmosphere where the pollution is more powerful. One expert estimates that if companies like Virgin Galactic, Blue Origin, and SpaceX offer more regular tourist flights, these emissions may warm the upper atmosphere enough to alter its circulation and undo progress patching the ozone hole. A stronger focus on sustainable fuels is needed – along with regulations on the number of lift-offs. 

Other experts have raised concerns about the impact of several tonnes of wreckage that land in our waters, including how it can impact airlines flying in the area of debris impact. The co-director of the Outer Space Institute believes the risks and costs of the spaceflight industry are being exported to the aviation industry. Even planned descents cause airline disruption.