The Japanese-built Kounotori 7 spacecraft is expected to send some 6,000 kilograms of science experiments, crew supplies and upgraded equipment to the ISS.
Inside the pressurized compartment will also be a small re-entry capsule, which serves as a technology demonstrator for a re-entry and sample-return vehicle. If all goes as planned, it will be recovered from the ocean and taken back to Japan.
In the unpressurized compartment, the freighter will carry several lithium-ion batteries to replace the outpost's existing nickel-hydrogen batteries. This is a continuation of the process that began with the Kounotori 6 mission in early 2017. Once at the station, at least two spacewalks by astronauts are required to replace the old hardware with the new upgrades.
The old batteries will be placed in the spacecraft's unpressurized compartment for disposal in the northwestern Pacific Ocean at the end of Kounotori 7's mission. Kounotori 9 (the last planned HTV model) is expected to continue the battery upgrades.