Major changes of Kounotori 5 from previous Kounotori are:
Solar panels were reduced to 49 panels, down from 57 on HTV-1 and Kounotori 2, 56 on Kounotori 3, and 55 on Kounotori 4, since the analysis of the data from previous missions showed that fewer panels were sufficient. A sensor-mount outlet was added since Kounotori 4 at a place previously occupied by a solar panel, and on Kounotori 5 it is used to attach environment measurement equipment.
Improvement in the loading of Cargo Transfer Bags allows for increased capacity, and more late access cargo.
When approaching the ISS, previous missions were held at the Approach Initiation point at behind the ISS for system checkout, but Kounotori 5 was changed to continue the approach without holding, to simplify the operation.
Cargo
Kounotori 5 was planned to carry about cargo, consisting of in the pressurised compartment and in the unpressurised compartment. Due primarily to the launch failure of SpaceX CRS-7, an additional were added as the late access cargo. Total cargo weight was. Pressurised cargo includes potable water, food, crew commodities, system components, and science experiment equipments. System components include: UPA Fluids Control and Pump Assembly, WPA Multifiltration Beds, a galley rack to be placed in Unity, and a Simplified Aid For EVA Rescue pack. Science experiment equipments include Mouse Habitat Unit, Electrostatic Levitation Furnace, Multi-Purpose Small Payload Rack, Exposed Experiment Handrail Attachment Mechanism, NanoRacks External Platform, and CubeSats. Unpressurised cargo consists of the Calorimetric Electron Telescope. Plans for a NASA unpressurised module were canceled. Upon departure from ISS, the unpressurised cargo bay will carry the Multi-mission Consolidated Equipment package, the Superconducting Submillimeter-Wave Limb-Emission Sounder, and a NASA experiment module, Space Test Program Houston 4, until its destructive reentry in Earth's atmosphere.
Operation
Launch and rendezvous with the ISS
Kounotori 5 was originally planned for launch in 2014 but was later postponed due to delays in the construction and qualification testing of the payload to fly on the capsule. In June 2015, it was scheduled to be launched at around 13:01 UTC on 16 August 2015. Due to the bad weather forecast, on 14 August 2015 the launch was postponed to August 17, and then on 16 August it was postponed again to 19 August 2015. Kounotori 5 was successfully launched with a H-IIB No. 5 carrier rocket flying from pad 2 of the Yoshinobu Launch Complex at Tanegashima at 11:50:49 UTC on 19 August 2015. Communication and three-axis attitude controls were established shortly after the launch. Phase Manoeuvre was performed by 19:25 UTC on 20 August 2015, and the first Height Adjustment Manoeuvre by 17:55 UTC on 22 August 2015. The second and third Height Adjustment Manoeuvre were performed by 03:07 and 06:12 UTC on 24 August 2015, respectively. The ISS's robotic arm SSRMS grappled Kounotori 5 at 10:29 UTC on 24 August 2015, and fastened it to the ISS's CBM at 14:58 UTC on 24 August 2015. All berthing operations were completed at 17:28 UTC on 24 August 2015.
Operation while berthed to ISS
From 02:27 UTC on 25 August 2015, the Exposed Pallet, which is carrying CALET, was extracted from Kounotori 5's Unpressurized Logistics Carrier by the ground-controlled SSRMS, and handed off to the Japanese Experiment ModuleRemote Manipulator System, which is also remote-controlled from ground. The JEMRMS then attached the palette to the JEM Exposed Facility. Later, at 14:29 UTC on the same day, CALET was removed from the pallet and installed to the Exposed Facility by the JEMRMS. The ISS crew opened the hatch of the Kounotori's Common Berthing Mechanism and entered to Pressurized Logistics Carrier at 10:24 UTC on 25 August 2015 and began transferring the cargo.
Departure from ISS and reentry into the Earth's atmosphere
Kounotori 5 was unberthed from the CBM at 11:12 UTC, 28 September 2015 by SSRMS robotic arm and moved to the release position. The first attempt of the release at 15:20 UTC was aborted due to an anomaly of the SSRMS. After one ISS orbit, Kounotori 5 was released from the SSRMS at 16:53 UTC, 28 September 2015, Expedition 45 Flight Engineer Kimiya Yui of JAXA, backed up by NASA Flight Engineer Kjell Lindgren, commanded the SSRMS. After the orbit control manoeuvre, Kounotori 5 reentered Earth's atmosphere over the southern Pacific Ocean around 20:33 UTC, 29 September 2015.
