Elon Musk is a man of clear vision. While most college students were out partying their brains out, Elon was busy pondering not just his upcoming exams or his future career… but the future of the entire human race. What he settled on way back then was that humanity needed sustainable transport and sustainable energy production. To round things out at a balanced trifecta, he also thought that humanity should be a much more exploratory space-faring civilization.
Fast forward a few decades and Elon is heavily involved in all 3 of these areas as the founder of SpaceX, CEO of Tesla Motors, and Chairman at SolarCity… but it’s not all roses and sunshine, as a few of these industries have some severe issues. Elon talks regularly about how he believes all transport will go electric with one ironic exception — space travel — which utilizes special blends of hydrocarbon-based rocket fuel and liquid oxygen.
With such a massive amount of energy required to escape the pull of gravity, and fossil fuels being the primary source of fuel, space travel — or more specifically, getting out of earth’s orbit — has a large carbon footprint which sits in stark contrast to the blue-sky solutions of solar power and sustainable transport.
Don Mackenzie, who heads up the Sustainable Transportation Lab at the University of Washington, where he is also an Assistant Professor of Civil & Environmental Engineering, took this idea and ran with it, calculating the carbon footprint of a space launch to the carbon emissions saved by driving a Tesla vs an average internal-combustion-engine (ICE) vehicle. Check this out:
“So it is a good time to ask: just how carbon intensive is a space launch? Let’s consider the Falcon 9 rocket from SpaceX. According to SpaceFlight101.com, the Falcon 9 v. 1.1 uses about 147,000 kg of RP-1 rocket fuel (similar to kerosene) and 341,000 kg of liquid oxygen, about 80% in the first stage and the rest in the second stage. If we assume the rocket fuel is similar to Jet-A, with a lower heating value of 43.2 MJ/kg and “well to wake” emissions of 85 gCO2-e/MJ (source), then the GHG emissions associated with the fuel are 147,000 * 43.2 * 85 = 540 x 106gCO2-e or 540 metric tonnes equivalent.
But that’s not all. Producing liquid oxygen takes energy too, to the tune of 638 kWh per tonne. Assuming 470 g of CO2 emitted for each kWh of electricity (based on EIA numbers for U.S. generation and emissions in 2015), then the emissions associated with producing the liquid oxygen are 341 * 638 * 470 = 102 x 106 gCO2, or 102 tonnes.
Putting the fuel and oxidant together, we get 640 metric tonnes CO2-equivalent per launch.
To put these numbers in perspective, let’s estimate the lifetime GHG savings of a Tesla Model S P90D (0.36 kWh / mile on electricity) relative to a BMW M5 (17 mpg on gasoline). There are other ways to compare these cars, of course:
Assuming a 150,000 mile life, and emissions intensity of 0.47 kg/kWh for electricity and 11 kg/gal for gasoline, we can estimate that the M5 will emit 97 tonnes CO2-equivalent over its life, while the Model S will emit 25 tonnes (including upstream emissions in both cases, of course). Thus, a Model S saves the equivalent of about 62 tonnes of CO2 over a 150,000 mile life.
In other words, it takes about 10 Teslas to offset the emissions of one Falcon 9 launch. So, if you’re considering a trip to orbit with 4 of your friends… realize that you’ll each be releasing more GHGs than an EV can save you in 25 years’ worth of driving.”
It is quite interesting to see the impact of each launch compared to something we can actually wrap our heads around — driving a car. Check out the full article at the link below: