The Japan Aerospace Exploration Agency (JAXA) successfully completed a ground combustion test of the Epsilon S rocket's second-stage engine on Thursday [1].
This milestone is critical for Japan's efforts to establish a reliable, low-cost satellite launch capability. A successful test of the propulsion system ensures the vehicle can meet the necessary performance benchmarks to reach orbit safely.
The test took place at the Tanegashima Space Center in Kagoshima Prefecture [1]. The operation began at 9 a.m. JST on July 23 [1]. JAXA officials said the results were successful shortly before 1 p.m. JST [1].
During the procedure, the M-35a engine, which utilizes components from an older engine model, underwent a combustion period of approximately 130 seconds [1]. The test allowed engineers to evaluate the performance and stability of the second-stage propulsion system under simulated flight conditions.
JAXA said the goal is to achieve a successful launch of the Epsilon S rocket, specifically the seventh vehicle, within the 2026 fiscal year [1]. The agency is utilizing these ground tests to verify the integrity of the hardware before the vehicle is integrated for flight.
The Epsilon S is designed to provide more flexible and frequent launch opportunities for small satellites. By refining the M-35a engine, JAXA aims to reduce the risk of failure during the ascent phase of the mission [1].
“The M-35a engine underwent a combustion period of approximately 130 seconds.”
The successful combustion of the M-35a engine removes a significant technical hurdle for the Epsilon S program. By verifying the second-stage performance, JAXA moves closer to operationalizing a launch vehicle that can compete in the growing global small-satellite market, reducing Japan's reliance on larger, more expensive rockets for smaller payloads.
