Sarah Walker, SpaceX’s director of Dragon Mission Management, said because the Draco thrusters on the capsule aren’t oriented optimally to perform a booster maneuver, SpaceX needed to design a new boost kit that would live in the unpressurized trunk.

She said SpaceX added some new attach points to the inside of the trunk in order to mount the propulsion system, which will be on all future trunks. Walker said the propellant tanks were used during the launch abort tests performed with Dragon in 2020 and the Draco engines were flown on the Crew-8 mission.

“Those are all mounted to this cargo rack assembly that we would normally mount unpressurized payloads to. We specifically added six propellant tanks, one pressurant tank, two Draco engines and a new heater and and insulation system to address the thermal considerations when these engines are firing for prolonged periods of time,” Walker said.