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H-II Transfer Vehicle KOUNOTORI (HTV)

HTV Overview

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

The HTV will be 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," will grapple 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, and the U.S. Space Shuttle, the Automated Transfer Vehicle (ATV), developed and built by the European Space Agency (ESA), and Japan's HTV will be utilized for delivering supplies to the ISS. Among these cargo-carrying spacecraft, the HTV is the only unmanned vehicle that can carry both pressurized and unpressurized cargo. This is a unique special feature of the HTV.

The HTV "Technical Demonstration Vehicle" (initial flight vehicle) has been successfully launched on September 11, 2009 (JST) from Tanegashima Space Center in Japan. Subsequently, one or two HTVs per year are planned for launch.

HTV specifications

HTV specifications
Item Specification
Length 9.8m (including thrusters)
Diameter Approx. 4.4m
Total Mass Approx. 10,500kg
Cargo capacity (supplies and equipment) Approx. 6,000kg
  -Pressurized cargo: 4,500kg
  -Unpressurized cargo: 1,500kg
Cargo capacity (waste) Approx. 6,000kg
Target orbit to ISS Altitude: 350km to 460km
Inclination: 51.6 degrees
Maximum duration of a mission Solo flight: Approx. 100 hours
Stand-by (on orbit): More than a week
Berthed with the ISS: Maximum 30 days
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