KITE was an experimental electrodynamic tether. The tether was equipped with a 20 kg end-mass, and would have been 700 m long when deployed. A maximum current of 10 mA was planned to run through the tether. Kounotori's ISS rendezvous sensor would have been utilized to measure how the end-mass moves during the test. The EDT experiment was scheduled following Kounotori 6's departure from the ISS, with a planned duration of one week. After the experiment, the tether would have been separated before the spacecraft proceeds with the de-orbit maneuvers. The main objective of this experiment were the orbital demonstration of both extending an uncoated bare-tether, and driving electric currents through the EDT. These two technologies will contribute to gaining capabilities to remove space debris.
Cargo
Kounotori 6 carries about 5900 kg of cargo, consisting of 3900 kg in PLC and 1900 kg in ULC. Cargo in the pressurized compartment includes 30 bags filled with potable water, food, crew commodities, CDRA Bed, TPF experiment unit, PS-TEPC radiation measurement instrument, ExHAM, HDTV-EF2 high-definition and 4K camera, new J-SSOD, and CubeSats. Cargo by NanoRacks includes TechEdSat-5, CubeRider, RTcMISS, NREP-P DM7, four Lemur-2. Additionally, the Blue SPHERES satellite of the MIT Space Systems Laboratory is being returned to the ISS for continued autonomous systems research. Cargo in the unpressurized compartment consists of six lithium-ion batteries and their associated adapter plates to replace existing nickel-hydrogen batteries of the ISS. Since each of the new lithium-ion battery has a capability equivalent to two of the current nickel-hydrogen batteries, the six new batteries will replace twelve old batteries, out of the 48 existing batteries of the ISS. On departure from the ISS, Kounotori 6 will carry 9 out of the 12 replaced old batteries which will be disposed by destructive reentry into Earth's atmosphere. The 3 remaining old batteries will stay on the ISS.
Operation
Launch
On 26 July 2016, the launch was scheduled for 30 September 2016, but on 10 August 2016, postponement was announced due to the leak from piping. The H-IIB launch vehicle carrying Kounotori 6 lifted off at 13:26:47 UTC on 9 December 2016, and 15 minutes 11 seconds later, Kounotori 6 was released into initial 200 km × 300 km orbit. SFINKS experiment payload began the data collection at 14:16, on 9 December 2016, but it stopped unexpectedly after 509 seconds. After a series of orbital manoeuvres, Kounotori 6 arrived to the proximity of ISS and captured by SSRMS at 10:39, on 13 December 2016. Kounotori was bolted to the CBM of the Harmony nadir port by 13:48 UTC.
Operation while berthed to ISS
Berthing operation completed at 18:24, on 13 December 2016 UTC, and the hatch opened at 19:44 UTC. Since 07:44, 14 December, Exposed Pallet was extracted from Unpressurised Logistics Carrier of Kounotori by SSRMS and transferred to Payload and ORU Accommodation. After a combination of two Extra-Vehicular Activities and robotic operations, the lithium-ion battery units and adapter plates were installed. The Exposed Pallet carrying old Nickel-hydrogen battery units was returned to Kounotori 6's Unpresurised Logistics Carrier on 23 January 2017.
Departure from the ISS and re-entry to the Earth atmosphere
SSRMS grappled and detached Kounotori 6 from the CBM of Harmony nadir port at 10:59, 27 January 2017, and Kounotori 6 was released at 15:45, on 27 January 2017. Following the undocking after moving to a safe distance from ISS, the Kounotori 6 was to demonstrate the "Kounotori Integrated Tether Experiment " using electrodynamic tether to demonstrate space debris removal technology. This experiment was planned for seven days before reentry to the Earth's atmosphere. On 31 January 2017, media reported some problems in extending the tether, bringing to doubt the experiment's success. A series of deorbit manoeuvres were performed at 08:42, 10:12, and 14:42 UTC, on 5 February 2017. Kounotori 6 reentered to Earth atmosphere over southern Pacific Ocean around 15:06 UTC, on 5 February 2017.
