A successful prototype rocket engine test powered by liquid biomethane (LBM) derived from cattle dung has been carried out by the Japanese space startup Interstellar Technologies Inc (IST).
The company conducted a series of 'Static Fire Test' for the ZERO launch vehicle rocket at the Hokkaido Spaceport's Launch Complex-0 in Taiki, Hokkaido.
During the experiment, the engine generated a horizontal blue-and-orange flame for about 10 seconds.
As per the official release, the biomethane was derived from cow dung gathered from local dairy farms, showcasing its potential benefits as an environmentally friendly rocket fuel.
Eco-friendly rocket fuel
This eco-friendly rocket fuel has been developed in partnership with Japan-based company Air Water.
The Air Water Group has implemented a regional circular supply chain centred in the Hokkaido Tokachi area, where biogas from livestock manure is converted into LBM.
The cooperative effort includes engaging local farmers who employ on-farm equipment to convert cattle manure into biogas. Air Water then acquires this biogas and processes it into the rocket fuel.
In addition to liquid biomethane, Zero uses liquid methane as a propellant, which offers various advantages. Low cost, fuel performance, availability, and environmental impact are among them.
Liquid methane has become a preferred choice for many space companies, including SpaceX, for their Starship.
Combustion chamber tech
Featuring a two-stage design, the rocket incorporates a pintle injector, which reduces the number of components and improves combustion efficiency.
"The number of components has been reduced to a tenth of conventional engines, fundamentally lowering the manufacturing costs of a rocket engine, estimated to constitute half of the overall expenses," said the press release.
The pintle injector delivers propellants (liquid fuel and oxidiser) into a rocket engine's combustion chamber in a controlled manner.
This technique is also employed in the engines of SpaceX.
To achieve excellent combustion performance, ZERO's combustion chamber has undergone research and development efforts in collaboration with Tokyo University and JAXA.
The successful tests are an important step toward the actual lift-off of this small satellite launch vehicle rocket by 2025.
Increasing demand for small satellite launch services globally
IST plans to use the fuel to launch satellites into low-Earth orbit. Zero aims to meet the increasing demand for small satellite launch services globally, particularly in the Asia and Oceania regions, according to the company.
"ZERO's space transportation service distinguishes itself with competitive pricing – at less than 800m JPY [€5.1m] per launch [in mass production] – made possible through an integrated development and manufacturing process," said the release.
Cattle manure could significantly contribute to carbon neutrality. Cattle release significant amounts of methane, a potent greenhouse gas that contributes to global warming.
The joint efforts of IST and Air Water are directed towards ensuring the majority of the rocket fuel is sustainable, thereby making a tangible contribution to the mitigation of climate change.