How much pollution did Jeff Bezos create during his trip to space? It turns out that when it comes to adding greenhouse gases to the atmosphere, Blue Origin’s New Shepard rocket is one of the cleanest launch vehicles around. However, climate change concerns from suborbital spacecraft could increase as similar flights take off in the near future.
Rockets are not exactly the greenest of technology, and their overall impact on the environment is still being studied. The majority of launches produce things like water vapor, carbon dioxide (CO2), soot, and aluminum oxides, depending on what type of fuel they use.
New Shepard, which billionaire Bezos took on its initial crewed flight yesterday (July 20), combined liquid hydrogen and liquid oxygen in its engine to generate thrust, meaning the main emissions from the rocket were “water and some minor combustion products, and virtually no CO2,” Darin Toohey, an atmospheric scientist at the University of Colorado, Boulder said.
Toohey also said that water in rocket exhaust can increase the number of clouds in the atmosphere, including the iridescent “mother-of-pearl” clouds often seen at sunset after a launch. These can impact the upper atmospheric layers known as the mesosphere and ionosphere. However, because the number of rocket launches is so low right now, they are not much of a concern in climate modeling.
But that could change as more rockets launch in the future.
Rockets accounted for around 0.0000059% of all CO2 emissions in 2018 (for comparison, the airline industry was around 2.4% of global CO2 emissions that same year). But even though ice and clouds can reflect sunlight back into space and reduce global heat, water vapor is a more potent greenhouse gas than carbon dioxide, and the longer that vapor remains in the atmosphere, the more it will heat our planet.
“The main concern when it comes to rocket flights are small particles such as soot and aluminum oxides,” Toohey said. “These can have a disproportionate impact on the atmosphere. A very small amount can make a big difference.”
In 2010, he and two other researchers modeled the effects of soot injected into the atmosphere from 1,000 private suborbital flights a year and found that they could increase temperatures over the poles by 1.8 degrees Fahrenheit (1 degree Celsius) and reduce polar sea ice levels by 5% to 15%.
But New Shephard’s engine doesn’t produce much in the way of particulates, Toohey said. “It might be among the cleanest of the fuels in that context.”