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Japan Aerospace Exploration Agency:JAXA
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H-II Transfer Vehicle KOUNOTORI (HTV)

HTV2 Mission Logo

HTV2 Mission Logo

HTV2 Mission

On the HTV2 Mission, JAXA’s H-II Transfer Vehicle (HTV), KONOTORI, will make the second flight to the International Space Station (ISS). During the HTV1 Mission (September 2009), the HTV maiden flight vehicle (HTV1) demonstrated its autonomous and remotely-controlled rendezvous capabilities while delivering cargo/supplies to the ISS.

Having achieved the remarkable performance during the HTV1 Mission, the HTV2 Mission will focus on ISS cargo transportation activities.


KOUNOTORI2 (HTV2) Mission Completed

KOUNOTORI2 (HTV2) Mission Completed (March 30, 2011)

The KOUNOTORI2 reentered Earth's atmosphere at 0:09 p.m. on March 30, over the East Coast of New Zealand. The KOUNOTORI2 successfully completed its cargo supply mission to the ISS.

the KOUNOTORI2 (HTV2) performed three de-orbit maneuvers for reentry

the KOUNOTORI2 (HTV2) performed three de-orbit maneuvers for reentry (March 30, 2011)

On March 30, the KOUNOTORI2 (HTV2) performed three de-orbit maneuvers for reentry into Earth's atmosphere. The third and final de-orbit maneuver was completed at 11:44 a.m.

KOUNOTORI2 (HTV2) Leaves the ISS

KOUNOTORI2 (HTV2) Leaves the ISS (March 29, 2011)

The KOUNOTORI2 (HTV2), which was unberthed from Harmony (Node 2) and moved to the release position below the ISS by the SSRMS, was released from the SSRMS at 0:46 a.m., March 29, 2011.

*All times are Japan Standard Time (JST)

» HTV2 Mission News

Mission Objectives

The HTV2 Mission’s primary objectives include launch of the second H-IIB launch vehicle, cargo delivery to the ISS, and support of the station’s trash disposal.

After the HTV1 Mission, some modifications were made to HTV’s original configuration and operational procedures based on the HTV1 mission results. During the HTV2 Mission, performances of the modified parts will be monitored. Major modifications are as follows.

HTV Pressurized Logistics Module (PLC)
  • Cargo loading capacity of the HTV Re-supply Rack (HRR) was increased by modifying its cargo layout
  • Cargo capacity of the PLC was increased by creating additional cargo spaces inside the PLC
  • Of four lights inside the PLC, two lights were replaced to domestic (Japanese) LED lights.

Avionics Module
  • The total number of onboard batteries was reduced. In addition, the onboard batteries were upgraded
  • Onboard rendezvous flight software was modified
  • Space Integrated GPS/Inertial Navigation System (SIGI) software was modified
  • Proximity Link System String B transponder was replaced to a domestic (Japanese) transponder

Propulsion Module
  • Some of the injection temperature sensors on the HTV’s Reaction Control System (RCS) thrusters were modified to increase the upper measurement range

Payload (Cargo)

KOBAIRO Rack (left), MSPR (right)

KOBAIRO Rack (left), MSPR (right)

The HTV2 delivers approximately 5,300 kg of cargo to the ISS.

For pressurized cargo, the HTV2 delivers JAXA’s two science racks, KOBAIRO Rack and the Multi-purpose Small Payload Rack (MSPR). This is the first time that the HTV delivers JAXA’s science experiment rack to the ISS. In addition, the HTV2 Mission delivers potable water to the ISS.

For unpressurized cargo, the HTV2 delivers NASA’s two Orbital Replacement Units (ORUs), the Cargo Transport Container (CTC) and the Flex Hose Rotary Coupler (FHRC), to the ISS. These unpressurized ORUs will be stored outside of the ISS for later use.

» Payload

HTV2 Mission Overview

HTV2 Mission Summary (Updated March 30, 2011)
Item Detail
HTV Flight Number HTV2 (KOUNOTORI 2)
Launch Time 2:37:57 p.m., January 22, 2011 (JST)
Launch Site Launch Pad2 (LP2), Tanegashima Space Center (TNSC)
Capture by the SSRMS 8:41 p.m., January 27, 2011 (JST)
Berthing to the ISS 3:34 a.m., January 28, 2011 (JST)
Unberthing by the SSRMS March 28, 2011 10:29 p.m. (JST)
Separation from the ISS March 29, 2011 0:46 a.m. (JST)
Reentry March 30, 2011 0:09 p.m. approx. (JST)
Mission Duration Approx. 67 days
Altitude Insertion Orbit: 200 km x 300 km (elliptical orbit)
Rendezvous: Approx. 350 km
Inclination 51.6 degrees
Multi-purpose Small Payload Rack (MSPR)
Supplies for onboard use (six HRRs)
HTV ULC Cargo Transport Container (CTC)
Flex Hose Rotary Coupler (FHRC)
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