Plan a multi-satellite delivery

Epsilon-5 launched the Innovative Satellite Technology Demonstration-2 mission on November 9, 2021. JAXA confirmed the release of all nine spacecraft. RAISE-2 separated about 52 minutes 35 seconds after liftoff; the remaining spacecraft were released later, over an interval extending beyond an hour after launch.

A common launch does not give every spacecraft the same scientific purpose or operational timeline. Each team still needs to establish communications and verify its own hardware. A launch report confirming release is valuable, but it is not a substitute for the later results of every experiment.

A shared launch needs mounting structures, suitable release mechanisms and an agreed sequence. The 2018 manual distinguishes the main payload adapter, small-satellite interfaces and CubeSat deployment equipment. These are different interfaces, not a universal socket that accepts any satellite without review.

Separation can also transmit shock to delicate equipment. Interface design therefore concerns loads and the release environment as well as fitting the spacecraft inside the fairing. The satellite team and launch provider must agree on requirements and show how the integrated arrangement meets them.

Include every part of the payload assembly

Consider an original exercise with a 500 kg allocation for a particular payload assembly. The spacecraft total 380 kg and the adapter assembly adds 70 kg. The combined 450 kg leaves 50 kg before that stated limit. These are fictional planning values, not Epsilon capacity figures or an approved margin policy.

A proposed extra 60 kg satellite would exceed the stated allocation by 10 kg, even before any extra adapter hardware. A spare deployment position alone does not establish capacity. Dimensions, structural loads, orbital requirements and separation clearance must also be checked before accepting another passenger.