This is an archive of information released in the past.

Disclaimer: It may contain broken links or outdated information. Some parts may not function in current web browsers.
*Visit for the latest information.


Japan Aerospace Exploration Agency:JAXA
  • contact us
  • Japanese

H-II Transfer Vehicle KOUNOTORI (HTV)

HTV Overview

The H-II Transfer Vehicle (HTV), developed and built in Japan, is an unmanned cargo transfer spacecraft that delivers supplies to the International Space Station (ISS).

The HTV is launched from the Tanegashima Space Center aboard an H-IIB launch vehicle with up to 6,000kg of supplies. When the HTV approaches close to the ISS, the Space Station Remote Manipulator System (SSRMS), known as "Canadarm2," grapples the HTV and berth it to the ISS. After the supplies, such as food, clothes and a variety of experiment equipment, are unloaded, the HTV will then be loaded with waste materials, including used experiment equipment or used clothes. The HTV will then undock and separate from the ISS and reenter the atmosphere. While the HTV is berthed to the ISS, the ISS crew will be able to enter and remove the supplies from the HTV Pressurized Logistics Carrier.

In addition to Russia's cargo spacecraft, Progress, the Automated Transfer Vehicle (ATV), developed and built by the European Space Agency (ESA), Cygnus Spacecraft developed by Orbital Sciences Corporation, SpaceX, and Japan's HTV are currently utilized for delivering supplies to the ISS. Among these cargo freighters, the HTV can carry both pressurized and large unpressurized cargo. This is the unique special feature of the HTV.

The HTV "Technical Demonstration Vehicle" (initial flight vehicle) was successfully launched on September 11, 2009 (JST) from Tanegashima Space Center in Japan. As of 2014, four HTVs, including its technical demonstration mission (HTV1) have successfully completed the missions.

HTV specifications

HTV specifications
Item Specification
Length Approx. 10.0m
Diameter Approx. 4.4m
Mass excluding cargo Approx. 10,500kg
Cargo capacity (supplies and equipment) Total:Maximum 6,000kg

Pressurized Logistics Carrier (PLC)Maximum 4,100kg
Unpressurized Logistics Carrier (ULC)Maximum 1,900kg

Total Mass Maximum 16,500kg
Reentry cargo capacity Maximum 6,000kg
Propellant Fuel:MMH (Monomethylhydrazine)
Oxidizer:MON3 (NTO containing 3wt% NO)
Insertion orbit Altitude: 350km-460km
Inclination: 51.6 degrees
Mission Duration Solo flight:Normally 5 days
Berthing:Maximum 45 days
Stand-by (on orbit): Normally 7 days
Copyright 2007 Japan Aerospace Exploration Agency Site Policy