Kounotori 6 (こうのとり6号機), also known as HTV-6, was the sixth flight of the H-II Transfer Vehicle, an uncrewed cargo spacecraft launched to resupply the International Space Station.

The main objective of this experiment were the orbital demonstration of both extending an uncoated bare-tether, and driving electric currents through the EDT.

[12] Cargo in the pressurized compartment includes 30 bags filled with potable water (600 liters),[13][14] food, crew commodities, CDRA Bed (Carbon Dioxide Removal Assembly), TPF (Two-Phase Flow) experiment unit, PS-TEPC (Position-Sensitive Tissue Equivalent Proportional Chamber) radiation measurement instrument, ExHAM (Exposed Experiment Handrail Attachment Mechanism), HDTV-EF2 high-definition and 4K camera, new J-SSOD (JEM Small Satellite Orbital Deployer), and CubeSats (AOBA-Velox III, TuPOD which comprises two TubeSats (Tancredo-1 and OSNSAT), EGG, ITF-2, STARS-C, FREEDOM, WASEDA-SAT3).

[28] After a series of orbital manoeuvres, Kounotori 6 arrived to the proximity of ISS and captured by SSRMS (Canadarm2) at 10:39 (10:37 according to NASA), on 13 December 2016.

[33] Since 07:44, 14 December 2016, Exposed Pallet (EP) was extracted from Unpressurised Logistics Carrier (ULC) of Kounotori 6 by SSRMS and transferred to Payload and ORU Accommodation (POA).

The Exposed Pallet carrying old Nickel-hydrogen battery units was returned to Kounotori 6's Unpresurised Logistics Carrier on 23 January 2017.