Energy Factoid: SpaceX rockets are powered by fossil fuels

Previous SpaceX rockets were powered by kerosene but the new Starship is powered by natural gas

The SpaceX launch of the Starship, which has been rescheduled for April 20, 2023, is the most powerful rocket ever built. Previous SpaceX rockets were powered by kerosene which is refined from crude oil:

Previous SpaceX Falcon rocket engines were powered by kerosene because there were no methane engines until 2007, and kerosene is cheaper, denser, and stable at room temperature. It’s easy to handle, is not toxic like hypergolic propellant, easily transportable, and has no leakage issue similar to liquid hydrogen.

The new Starship is powered by Merlin engines were developed by SpaceX for use on its Falcon 1, Falcon 9, and Falcon Heavy launch vehicles. Merlin engines use a mixture of chilled methane and oxygen called Methalox. In an article titled “SpaceX’s New Fuel is More Efficient and Environmentally Friendly,” the space blog Eclipse Aviation described methane as follows:

SpaceX is using a new fuel to power its rockets because it is more efficient than the traditional fuel that has been used in the past. The new fuel, called methane, is less expensive and more environmentally friendly. It is also more powerful, which means that SpaceX can use less of it to power its rockets (emphasis added).

This is the same methane, or natural gas, that has become the backbone of electricity generation in the U.S. and is used in 40% of households to cook food on gas stoves. Ironically, this is the same natural gas that is used in gas stoves that our government agencies are trying to ban.

The chemical definition of methane is CH4 which describes its chemical makeup as four hydrogen atoms bound to one carbon atom. Stripping out that single carbon atom leaves pure hydrogen, the fuel of green dreams. As with the many molds that Elon Musk has broken, he decided to use methane instead of hydrogen to power his heavy rockets because hydrogen is very volatile, difficult to handle, prone to leakage, and expensive. Musk did what all self-respecting profit-maximizing entrepreneurs do: he used the most cost-effective fuel.

All of this takes me to this final point. Elon Musk's choice of natural gas to power SpaceX rockets once again shows that it is a near-perfect fuel due to its availability (the U.S. has hundreds of years of natural gas reserves), the ease of transporting it through pipelines, its many uses as feedstock for thousands of products we depend on every minute of every day, and its use as the most important base-load fuel for the generation of electricity. Now we can add to the list its use as the fuel of choice to send rockets into space.