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HTV 1, ..., 9 (Kounotori 1, ..., 9)


The HTV (H-2 Transfer Vehicle) or Kounotori is an uncrewed, non-reusable cargo spacecraft for delivering pressurized and unpressurized cargo to the International Space Station. Launched by an H-2B-304 rocket, it maneuvers to the vicinity of the ISS, where the Canadarm-2 grapples the HTV and berths it to Node-2.

The HTV consists of four main components:

  • A propulsion module installed at the rear and composed of main engines for orbit change, Reaction Control System (RCS) thrusters for position control, fuel and oxidizing reagent tanks, and high-pressure air tanks; The HTV-1, 2 and 4 used four R-4D engines, all other use four IHI HBT-5 engines for propulsion.
  • An avionics module installed in the center part, with electronic equipment for guidance control, power supply, and telecommunications data processing.
  • A unpressurized logistics carrier to carry material on exposed pallets to the ISS. This section is open on one side to allow the Canadarm-2 to grapple the exposed pallet.
  • A pressurized logistics carrier to carry materials to be used on board of the ISS. This section is fitted with a CBM (Common berthing mechanism) to allow the spacecraft to be docked with the ISS and the crew to enter the pressurized section of HTV.

Electrical power is provided by body mounted solar cells.

HTV has a cargo capacity for supplies and equipment of max. 6,000 kg in total. The pressurized cargo can be max. 5,200 kg and the unpressurized cargo max. 1,500 kg. It can deorbit 6,000 kg of waste.

The maximum duration of a mission solo flight is approx. 100 hours. It can stay on stand-by on orbit for more than a week. The berthed time with the ISS is up to 30 days.

At the end of the mission, the HTV is unberthed from the ISS by the Canadarm-2 and it is deorbited to a destructive reentry.

HTV-6 carried the EDT tether experiment to be conducted after departing from the ISS. It failed to deploy.

Nation: Japan
Type / Application: Supply
Operator: JAXA (ex NASDA)
Contractors: Mitsubishi Electric (MELCO)
Propulsion: 4 × R-4D-11 (#1, 2, 4) or 4 × IHI HBT-5 (#3, 5-7)
Power: Solar cells (body mounted), batteries
Lifetime: 30 days
Mass: 16500 kg
Orbit: 400 km × 400 km, 51.6 (typical)
Satellite COSPAR Date LS Launch Vehicle Remarks
HTV 1 2009-048A 10.09.2009 Ta YLP-2 H-2B-304 with HREP, SMILES
HTV 2 (Kounotori 2) 2011-003A 22.01.2011 Ta YLP-2 H-2B-304
HTV 3 (Kounotori 3) 2012-038A 21.07.2012 Ta YLP-2 H-2B-304 with SCaN-Testbed, MCE, Raiko, WE WISH, FITSat 1, F 1, TechEdSat 1
HTV 4 (Kounotori 4) 2013-040A 03.08.2013 Ta YLP-2 H-2B-304 with STP-H4, TechEdSat 3, ArduSat X, ArduSat 1, PicoDragon
HTV 5 (Kounotori 5) 2015-038A 19.08.2015 Ta YLP-2 H-2B-304 with CALET, Flock-2b 1, ..., 14, SERPENS, S-CUBE, GOMX 3, AAUSAT 5
HTV 6 (Kounotori 6) 2016-076A 09.12.2016 Ta YLP-2 H-2B-304 with EDT, Lemur-2 18, ..., 21, TechEdSat 5, EGG, TuPOD, AOBA-VELOX 3, STARS C, FREEDOM, ITF 2, Waseda-SAT 3, OSNSAT, Tancredo 1
HTV 7 (Kounotori 7) 2018-073A 22.09.2018 Ta YLP-2 H-2B-304 with HSRC, SPATIUM 1, STARS-Me, RSP 00
HTV 8 (Kounotori 8) 2019-062A 24.09.2019 Ta YLP-2 H-2B-304 with AQT-D, RWASAT 1, NARSScube 1
HTV 9 (Kounotori 9) 2020-030A 20.05.2020 Ta YLP-2 H-2B-304 with iSIM

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