A Japanese space infrastructure company recently completed a successful test of a rocket powered by fuel made from… cow poop.
According to Interstellar Technologies Inc. – a comprehensive space infrastructure company based in Hokkaido, Japan – the “new milestone” was a fire test of a small satellite launch vehicle called ZERO. It is fueled by Liquid Biomethane (LBM).
“An anaerobic digester will partially convert manure to energy in the form of biogas which contains methane,” said Penn State extension of this type of fuel. Interstellar said that the successful test demonstrated the potential of biomethane as a sustainable type of rocket fuel and is a world-first for a private rocket company. Testing began Nov. 28 and is scheduled to run through the end of January.
Other types of rocket fuel include liquefied hydrogen, which is used to power NASA’s space shuttle. Liquid oxygen is also used as the oxidizer along with the LBM fuel in the ZERO rocket.
“This marks the inaugural adoption by IST of the gas generator cycle, which burns some of the propellants in a gas generator to drive a turbopump at tens of thousands of rotations per minute and deliver the fuel to the combustion chamber at high pressure,” said the Interstellar press release. “Additionally, the regenerative cooling effectively utilizes the fuel for cooling purposes within the combustion chamber walls. Tests for the combustion chamber, turbopump, and gas generator have been conducted, with future plans to integrate them.”
ZERO, has a combustion chamber designed in-house that adopts the pintle injector utilized in SpaceX’s engines. Space X is based in the U.S.
and run by Elon Musk and it has completed numerous launches into space.
“Although pintle injectors are generally known to have limited performance, research and development efforts with Tokyo University and JAXA Space Innovation through Partnership and Co-creation (J-SPARC) have led to design improvements that achieve high combustion performance,” said Interstellar.
“As a result, the number of components has been reduced to one-tenth of conventional engines, fundamentally lowering the manufacturing costs of a rocket engine, estimated to constitute half of the overall expenses.”
Liquid methane has also become a fuel of choice for rocket launches due to its competitive price and other factors, such as environmental impact. It is also used for SpaceX’s Starship.
“Recognizing the need for high-purity methane free of impurities in rocket propellants, IST has been deliberating on the procurement methods since selecting liquid methane as the fuel in 2020,” said Interstellar.
At the same time, Air Water Group established a regional circular supply chain centered around livestock manure. This cow dung from the Hokkaido Tokachi area is what the LBM fuel was derived from. To create the fuel, methane is separated, refined and liquefied.
“It achieves the same high purity (99% or higher) as conventional rocket fuels used in the past,” Interstellar explained. “IST, impressed by the performance and procurement excellence of LBM, has decided to adopt Air Water’s LBM as the fuel for the ‘ZERO’ rocket.”
Benefits of using manure as a source for fuel don’t end with affordability. According to Interstellar, use of LBM will help climate change mitigation efforts since methane is a potent greenhouse gas.
“Anaerobic digestion (AD) of dairy manure in the United States (U.S.) has many environmental and economic benefits, including producing renewable energy and reducing greenhouse gas emissions, and is underutilized as a manure treatment option,” said the U.S. Environmental Protection Agency.
Additionally, Interstellar said that livestock manure in the Hokkaido region poses other problems, such as odor and water pollution.
“As a Hokkaido-based company surrounded by a thriving dairy industry, [Interstellar] actively contributes to local energy self-reliance and environmental solutions,” said the company. Hokkaido is a major area of livestock production in Japan, per Hokkaido University.
Going forward, Interstellar intends for ZERO to be used as a small satellite launch vehicle designed to target a growing market for small-sized satellites.