J-I SRB Based

J-1 SRB variant

Mission Profile

The J-I SRB Based was a proposed Japanese two-stage launch vehicle concept studied around 2001, intended to leverage solid rocket booster technology derived from the Mu family for a simplified, lower-cost orbital delivery system. Designed with two stages, the concept explored whether existing SRB hardware could be repurposed into an affordable dedicated small-payload launcher. While never advanced beyond the concept phase, it reflected Japan's ongoing exploration of cost-effective launch architectures during a period when reducing access-to-space costs was a priority for ISAS and NASDA.