H-II Transfer Vehicle

The HTV is an unmanned cargo spacecraft which is used to deliver supplies to the International Space Station. A unique feature of the HTV is that it carries both pressurized and unpressurized cargo.

The first launch of the HTV, called a "Technical Demonstration Vehicle", took place on 10 September 2009. Re-entry and planned disintegration occurred 1 November 2009.
HTV-2, called "Kounotori" 2 gouki ("White Stork" Unit 2), was launched 22 January 2011. Re-entry and planned disintegration took place 30 March 2011.
HTV-3 (Kounotori 3) was launched 21 July 2012.
HTV-4 (Kounotori 4) was launched 3 August 2013.
HTV-5 (Kounotori 5) was launched 19 August 2015.
HTV-6 was launched 9 December 2016.
HTV-7 was launched 22 September 2018.
HTV-8 was launched 24 September 2019.
HTV-9 was launched 20 May 2020.

There are four modules making up the HTV.

• The Propulsion Module has fuel tanks and is equipped with 32 thrusters for orbital control.
• The Avionics Module has the electronics needed for power, communication, and navigation.
• The Unpressurized Logistics Carrier carries the Exposed Pallet. The Exposed Pallet in turn will carry the unpressurized cargo. This can be payloads for Kibo's Exposed Facility, or ISS battery Orbital Replacement Units.
• The Pressurized Logistics Carrier is used for supplies used on board the space station. The station crew can move back and forth between the station and the pressurized module.

Credit: JAXA

The HTV is launched with an H-IIB rocket. After launch, it is controlled from the ground for about 3 days as it makes its approach to the ISS. Once it is within range of the ISS (about 23 km), control shifts to the ISS. Once the HTV has closed to about 10 meters of the ISS, its thrusters are shut down and the HTV is grappled by the station's Canadarm2 and berthed to the Harmony Node 2.

While docked with the ISS, hatches are opened to allow free access to the pressurized module. The Canadarm2 is used to unload the unpressurized module. After all supplies have been unloaded from the HTV, it will be loaded with waste from the space station. It is then undocked and deorbited over the South Pacific where it will be destroyed upon reentry to the atmosphere.

Credit: JAXA	Credit: JAXA
Artistic representation of HTV approaching the ISS	Artistic representation of the HTV being unloaded

The H-IIB, is an upgraded version of the H-IIA launch vehicle currently in use by Japan.

Credit: JAXA	Credit: JAXA
H-IIA on the launch pad	H-IIB concept drawing

HTV Launches

Page last modified: 04 November 2023 19:28:49.