According to The Nikkei Asian Review, the rocket engine roared to life with a burst of bright orange flame, firing at 70% of full power for five seconds in a test that featured fuel used to power much of the planet but not harnessed to reach outer space: liquefied natural gas.
Interstellar Technologies, a small Japanese rocket startup, conducted this static firing parallel to the ground in mid-March at its site on Japan's northernmost main island of Hokkaido.
Interstellar plans to use the LNG engine for its Zero satellite launch vehicle, slated for takeoff in 2023. The company is developing the technology and aims to become a global pioneer in rockets powered by liquefied natural gas.
The startup employed an ethanol engine for the May 2019 launch of its Momo-3 suborbital rocket, which reached an altitude of 100 km. But the Zero weighs 36 tons, over 30 times more than the Momo-3, and must be able to maintain a speed of 8 km per second at its peak altitude of 500 km for a successful satellite launch. This means the Zero needs a more energy-dense fuel than ethanol.
LNG, which is composed mainly of methane, is relatively inexpensive, at less than $3 per kilogram -- one-tenth the price of the highly refined kerosene used in some rockets. As tests can burn tens of thousands of dollars in fuel, finding ways to reduce these costs is vital.
LNG also is environmentally friendly in comparison. It vaporizes if spilled, preventing soil or water pollution, and generates lower carbon dioxide emissions when burned. The fuel can even be procured locally, as Hokkaido produces biogas from livestock waste.
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