Blue Origin's New Glenn explodes on the launchpad at Cape Canaveral on May 28, 2026. @JConcilus via APGoing straight up is hard. It takes a lot of energy. For those of us who enjoy hiking, cycling or running, hills are the bane of our existence. The hills sap us of our strength and speed, and they require more effort than we often want to expend.Rockets are the ultimate definition of vertical ascent: They go up, fast. They need lots of raw power, and they need it immediately. Interestingly, though, the modern incarnation of reusable rocketry has come back to the same basic fuel as the human body uses: hydrocarbons. Granted, SpaceX and Blue Origin’s massive rockets are not using sugar, carbs or fats, but they are using the simplest hydrocarbon, methane: a single carbon atom with four hydrogen atoms around it, CH₄. A methane molecule is made up of a carbon atom surrounded by four hydrogen atoms. Christinelmiller/Wikimedia Commons, CC BY-SA As a physical chemist, I get to explore how molecules produce and absorb energy. I have seen how various chemicals have different benefits and drawbacks for a variety of energy applications. Orchestrating the pros and cons is like how different plays in football accomplish the same goal of getting the ball down the field but do so with distinct approaches. None are perfect, and some are more spectacular than others.A different type of fuelThe use of methane as a component of rocket fuel is different from what was used during Apollo or in the earlier crewed space rockets, and even in the space shuttle main engines. In all those rockets, hydrogen gas was the primary fuel. In the simplest terms, hydrogen in the form of H₂ reacts with oxygen – O₂, the same stuff you breathe – to produce water and a copious amount of energy. Hydrogen itself is light, and this reaction is incredibly efficient. The power-to-weight ratio of such fuel is astronomical, and it moves mass off the surface of our planet really well and quickly. However, H₂ is no panacea and has arguably more drawbacks than benefits. Being so small, the hydrogen molecules can actually seep through the walls of most fuel tanks. Preventing them from doing so requires special materials – expensive materials. To combat this problem, the hydrogen is liquified. But to do so, it must first be cooled to temperatures that would freeze the feathers off a penguin: minus 400 degrees Fahrenheit (minus 250 Celsius). Again, this process is expensive. Then, it takes awhile to fill the tanks on the rocket that hold the liquified hydrogen. You have to do this slowly to keep the liquified form from clogging and fouling up the fuel lines – and that’s also expensive.To combat these issues, SpaceX and Blue Origin have opted for methane instead of liquified hydrogen in their Starship and New Glenn rockets. While methane is still typically liquified and must be cold to do so, cooling it to minus 260 F (minus 162 degrees C) is much less expensive than minus 400, as would be needed for H₂. The methane molecules are also much larger than the hydrogen molecules, measuring more than twice as far across from their furthest points. Hence, it doesn’t weasel its way through the storage tanks and fuel lines like H₂ does. As a result, methane can be transported and filled into tanks much easier and faster. Then, since methane isn’t as leak-prone and stores better, the whole rocket ship itself can actually be reused; that makes the entire launch process cheaper overall. Methane: For rockets, but not just for rocketsSo methane is cheaper and affords reusability, but is it somehow safer than liquid hydrogen? Well, on May 28, 2026, the folks at Blue Origin found out how explosive methane can be. While the cause has yet to be reported, somehow the methane in the tanks ignited, resulting in an epic explosion seen dozens of miles away from the launchpad. Blue Origin’s rocket exploded on the pad during a test fire on May 28, 2026. Yes, a methane-fueled rocket can fling astronauts into the sky in ways that seem magical, but if anything goes wrong, methane still goes boom in a very destructive way.The reaction of hydrocarbons is actually the same type of explosion that fuels automobiles. The difference is that the explosion in a car engine cylinder drives the motion of a piston. In cars, the explosion of octane, a hydrocarbon eight times the size of methane, is directed with a purpose, creating what physical chemists like me call work. Heat is simply the same thing as work, but it just goes in random directions and does not accomplish some desired task. Kicking a football through the uprights is like work, while missing the ball is like heat. Hence, methane in a rocket directed through a nozzle does work to send the craft into the sky. If undirected, the hydrocarbon reaction produces heat in the form of an explosion that sets back years of planning for Jeff Bezos. This type of accident is relatively common in rocketry, as SpaceX has had its fair share of explosions. Getting all the right pieces to sync is a challenge, but decades of successful spaceflight indicate that this a surmountable issue.The reaction of hydrocarbons with oxygen in car engines or even rockets is, in a way, the same chemistry as what human bodies do in metabolism. Some hydrocarbons like sugar or a carbohydrate – but not the methane of rockets or the octane of cars – reacts with the oxygen that you breathe to produce carbon dioxide and water. Your body just performs this reaction slowly and in each cell, all over, warming you up.The rocket, however, is powered by a reaction between methane and oxygen in a single point at the nozzle. The energy is concentrated and directed together to fling the ship into space – unless, of course, it explodes in an uncontrolled fireball.Ryan C. Fortenberry receives funding from NASA.