The Environmental and Moral Implications of Human Space Travel
Humans have long dreamed of traveling to space. In response to the recent increase in commercial space flight, this paper evaluates environmental impacts of human space travel, both past and present, to shed light on the large environmental footprint of such activities. We find that the hourly impact from sustaining humans in space is around 1200 kg CO 2 -eq per hour. To put this into context, this is 1500 global citizen equivalents (GCE), i.e. 1500 times greater than the emission rate of the average person on the globe, and more than 500 times greater than the average person in the U.S. In terms of more familiar activities, this is equivalent to continuously supplying 2.9 MW of electricity from the U.S. grid for each space traveller (2000 times average U.S. per capita power usage), simultaneously driving fifty diesel buses, or occupying 16 seats on a Boeing 747 that never lands. Clearly such impacts raise questions not only to the sustainability of such activities, but also to the moral and ethical implications where such travel is limited to only the very wealthiest, but the costs are borne by all with few benefits to show from the endeavour