KAIROS
A small rocket with three solid-fuel stages and a small liquid-fuel upper stage, rated for 150 kg to sun-synchronous orbit. Space One aims for 20 launches a year by the end of the 2020s, but its first three flights failed.
Why it matters
Space One wants to give satellite makers in Japan a domestic ride on short notice, with launch within a year of signing and satellites handed over just four days before liftoff.
How the technology works
KAIROS stacks three solid-fuel stages and a liquid-fuel upper stage in an 18 meter, 1.35 meter wide body weighing about 23 tonnes. Solid motors can be stored fueled and launched quickly.
Space One quotes 150 kg to a 500 km sun-synchronous orbit and 250 kg to a lower-inclination orbit.
Sources
Updated Oct 22, 2026 · How we source facts · Suggest a correction