Natural Gas is Taking America to the Moon, Mars, and Beyond

  • Adam Kay
  • On the Texas coast, a rocket the size of a skyscraper is almost ready for its inaugural flight. SpaceX’s Starship, a gleaming steel behemoth that promises to unlock the solar system for America and for humanity, has immense potential. What you might not know is that Starship is fueled by natural gas.

    Starship is intended to be a fully reusable super heavy-lift launch vehicle, capable of transporting 100 tons of cargo to orbit, with a target cost of $10 per kilogram. For comparison, the Space Shuttle Columbia cost approximately $65,400 per kilogram transported to orbit. This quantum leap in capability is due in large part to natural gas.

    Traditionally, many rockets use a combination of hydrogen and oxygen to fuel their engines. But a fully reusable super heavy-lift rocket required something a little more innovative. Enter SpaceX’s Raptor 2 engine, powered by a mix of natural gas and oxygen. The high density of natural gas allows Raptor 2 engines to achieve 230 tons of thrust each, with a final goal of 250 tons of thrust. Starship will have 33 of these absurdly powerful Raptor 2 engines. The use of natural gas allows these engines to be far simpler than is typical in a rocket engine, allowing SpaceX to build an average of an engine a day, keeping up with demand. In comparison, the Hydrolox engines used by the Space Shuttle and by NASA’s new SLS rocket require a build time of between five and six years.

    There are other reasons to use natural gas as rocket fuel. The Sabatier reaction allows natural gas to be refined from the air on Mars, making it the ideal choice for any future missions to, and from, Mars. Additionally, when liquified, natural gas shrinks to approximately 1/500th of its gaseous volume, allowing for unparalleled fuel compression. NASA views natural gas as an excellent rocket fuel because it is “clean-burning, dense, and efficient” as a propellant, matching the density of kerosene and the efficiency of hydrogen. Thanks to America’s natural gas reserves, it’s also cheap, in addition to being easy to handle and safer than alternative rocket fuels.

    Assuming Starship launches and works as promised – which, as of now, remains to be seen – it will usher in a new era for manned spaceflight. Slashing the cost per kilogram transported to orbit would allow scientists and industry to use heavier but cheaper materials, massively lowering the cost of payloads in production as well as transport. Economies of scale, from space tourism to asteroid mining and zero-gravity manufacturing, could transform the American economy by opening new economic frontiers and the limitless resources of the solar system. Large-scale research bases, and potentially even colonies, could become possible.

    Future historians might look back on this as a watershed moment unparalleled in human history. If they do, it will be thanks to natural gas.