There has been much made of the idea that given our need to cut carbon emissions, space flight should go out of the window.
However, would you be surprised to hear that a SpaceX rocket emissions is roughly equivalent to 1 large jet crossing the Atlantic. Given that last year there was an average of roughly 1700 transatlantic flights each day in 2018, that is actually a relatively small amount.
Now given many people would argue we should not be flying either, this is not an equivalence that many people would look at. However, there are many different things that can in theory be done in space, that cannot be done on earth.
As the price of space flight comes down, many of these may become possible.
One of the interesting ideas that Elon Musk has floated, is to create the fuel on earth. Why is this an advantage? Well, if you absorb the elements from the air, then combine them, and then burn them in flight – your flight is essentially carbon neutral.
Point to point flights are something that Elon Musk has talked about. Even more interesting, the sub orbital flights that spacex has talked about would only use about 25% of the fuel. Elon Musk has also suggested that these flights might carry 1000 people. Given a standard plane usually carries around 500 (though this number can get very low and go a bit higher) on a transatlantic flight, but takes on average half as many people – the carbon footprint per person should be half as high. This does put the carbon footprint a little more in perspective, and explains why, while commercial flight is a concern with global warming and space exploration is a rounding error.
