NASA wants to know how the launch industry’s chic new rocket fuel explodes

For more than 60 years, nearly every major rocket has used some combination of the same liquid and solid propellants. Refined kerosene was preferred for its easy handling and non-toxic, hydrazine for its storage capacity and simplicity, hydrogen for its efficiency, and solid fuels for their long shelf life and rapid launch capability.

About 15 years ago, rocket companies began serious development of large methane-fueled engines. SpaceX and Blue Origin are now building the most powerful of these new engines – the Raptor and BE-4 – each capable of generating more than half a million pounds of thrust. SpaceX’s Starship rocket and its massive boosters are powered by 39 Raptors, while Blue Origin’s New Glenn and United Launch Alliance’s Vulcan rockets use a smaller number of BE-4s on their booster stages.

These “methalox” engines have several advantages by burning methane in combination with liquid oxygen. Methane is better suited for reusable engines because they leave less soot residue than kerosene, which SpaceX uses on the Falcon 9 rocket. Methane is easier to handle than liquid hydrogen, which is prone to leakage and must be stored at extremely cold temperatures of minus 423 degrees Fahrenheit (minus 253 degrees Celsius). Methane is also a cryogenic liquid, but its temperature is closer to that of liquid oxygen, between minus 260 and minus 297 degrees Fahrenheit (minus 162 to minus 183 degrees Celsius).

A Chinese rocket becomes the first methane-fuelled launcher to reach orbit in 2023. In the United States, Rocket Lab, Stoke Space, and Relativity Space are also developing methane-fueled engines for their next generation launch vehicles.

But rockets sometimes explode. The U.S. Space Force and NASA, the agencies responsible for range safety at America’s federally owned space ports, want to better understand how the dangers of an exploding Methalox rocket might differ from other launchers. This is important as launches have become more regular, with companies expecting multiple flights per day from launch pads that are, in some cases, only 1 or 2 miles away.

“We There just aren’t the analyzes that can say, ‘Hey, from a testing perspective, how much can we reduce BDA and still be safe?'” Col. Brian Chatman, commander of the Eastern Range at Cape Canaveral Space Force Station in Florida, said in a roundtable with reporters last year.

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Launch pads for Methalox rockets are now operational or under construction on government property at Kennedy Space Center and Cape Canaveral Space Force Station in Florida, Vandenberg Space Force Base in California, and NASA’s Wallops Flight Facility in Virginia. SpaceX is currently launching Starship test flights from South Texas on private property. The Federal Aviation Administration has public safety jurisdiction there.