|Mission type||ISS resupply|
|Mission duration||35 days|
|Spacecraft type||H-II Transfer Vehicle (HTV)|
|Manufacturer||Mitsubishi Heavy Industries (MHI)|
|Launch mass||15900 kg|
|Dry mass||10500 kg|
|Start of mission|
|Launch date||3 August 2013, 19:48:46 UTC|
|Rocket||H-IIB No. 4|
|Launch site||Tanegashima, Yoshinobu-2|
|Contractor||Mitsubishi Heavy Industries|
|End of mission|
|Decay date||7 September 2013, 06:37 UTC|
|Reference system||Geocentric orbit|
|Regime||Low Earth orbit|
|Berthing at ISS|
|RMS capture||9 August 2013, 11:22 UTC|
|Berthing date||9 August 2013, 15:28 UTC|
|Unberthing date||4 September 2013, 12:07 UTC|
|RMS release||4 September 2013, 16:20 UTC|
|Time berthed||25 days, 20 hours, 29 minutes|
Kounotori 4, also known as HTV-4, was the fourth flight of the H-II Transfer Vehicle, an uncrewed cargo spacecraft launched in August 2013 to resupply the International Space Station. It launched from Tanegashima Space Center aboard H-IIB No. 4 (H-IIB F4) rocket on 3 August 2013 and connected to ISS by 9 August 2013; it carried 5,400 kilograms (11,900 lb) of cargo. Kounotori 4 undocked on 4 September 2013 and was destroyed by reentry on 7 September 2013.
Major changes of Kounotori 4 from previous HTV are:
Kounotori 4 carries about 5,400 kilograms (11,900 lb) of cargo, consisting of 3,900 kilograms (8,600 lb) in the pressurized compartment and 1,500 kilograms (3,300 lb) in the unpressurized compartment.
Pressurized cargo include: CANA (Cabin network system for Kibō), Stirling-Cycle Refrigerator (FROST), ISS Cryogenic Experiment Storage Box (ICE Box), i-Ball and Re-Entry Data Recorder (REDR), four CubeSats: (PicoDragon, ArduSat-1, ArduSat-X, TechEdSat-3p), and the Kirobo (robot companion for Koichi Wakata).
Unpressurized cargo include: MBSU (Main Bus Switching Units) and UTA (Utility Transfer Assembly) which are ISS system spare parts, and a NASA experiment module STP-H4 (Space Test Program - Houston 4).
Kounotori 4 was successfully launched atop a H-IIB carrier rocket flying from pad 2 of the Yoshinobu Launch Complex at Tanegashima Space Center at 19:48:46 UTC on 3 August 2013. After 5.5 days of orbital manoeuvres, it arrived to Approach Initiation Point (5 kilometres (3.1 mi) behind ISS) at 05:31 UTC, 9 August 2013, and started the final approach sequence at 08:05 UTC. The ISS's robotic arm Canadarm2 grappled Kounotori 4 at 11:22 UTC, and fastened to ISS's Common berthing mechanism (CBM) on 16:32 UTC. All berthing operations were completed at 18:38 UTC.
The ISS crew opened the hatch and entered to Pressurized Logistics Carrier (PLC) at 11:11 UTC, 10 August 2013.
Kounotori 4 undocked from the ISS at 16:20 UTC, on 4 September 2013, Karen Nyberg then used the stations Canadarm2 to manoeuvre HTV-4 away from the International Space Station.
Trajectory after the release was controlled so that the reentry coincides with ISS passing over to observe it. Japanese flight controllers have deorbited HTV-4 on 06:11 UTC, on 7 September 2013, and it reentered to the atmosphere around 06:37 UTC, on7 September 2013.