H-II Transfer Vehicle KOUNOTORI (HTV)

A World's First Successful Demonstrative Mission of On-orbit Wireless LAN Communication and Transmission of Monitored Docking Images!

On May 25, 2020, videos taken by the camera installed on the H-II Transfer Vehicle "KOUNOTORI9" (HTV9) were successfully transferred to the ISS using wireless LAN (WLAN) in the vehicle's upward approaching phase for capture. This is the world's first successful image transmission using WLAN between two spacecraft in space.

The demonstrative experiment "Wireless LAN Demonstration" (WLD) comprises taking of videos of the ISS coming closer or departing with a camera installed in a spacecraft and transmission of these videos to the ISS on a real-time basis using WLAN so that onboard astronauts in the ISS can be aware of the spacecraft's current conditions. It is conducted with a view to achieving automatic docking in the future.

During the mission conducted on May 25, the WLAN communication with the ISS were established at around 600m beneath the ISS, earlier than initially planned (250m beneath), and the images taken with a camera installed on the HTV9 were uninterruptedly transmitted to the ISS in a stable manner for four hours.

When the HTV9 was positioned at 30m beneath the ISS, correct switching between the JAXA system on the tip of the robotic arm of the Japanese Experiment Module "Kibo" with which communication had been established and the NASA system was successfully performed as a demonstration test of switching of the WLAN access point on the ISS.

Thus, the targeted goal of the WLD mission has been attained: correct operation of the system required for the automatic docking experiment of the new ISS transfer vehicle "HTV-X2" has successfully been demonstrated.

A similar demonstrative experiment is planned for the HTV9 during its return journey from the ISS.

Schematic drawing of video acquisition with a monitor camera while KOUNOTORI9 (HTV9) is approaching the ISS (outward journey) (Credit: JAXA/NASA)

H-II Transfer Vehicle "KOUNOTORI" (HTV)

The H-II Transfer Vehicle (HTV) also known as "KOUNOTORI" is an unmanned cargo transfer spacecraft developed and operated by JAXA for delivering supplies to the International Space Station (ISS). KOUNOTORI is capable of delivering up to six tons of cargo and has the world's largest transportation capacity. It also has the world's unique capability of carrying foods, clothes and large-sized extra- and intravehicular experimental devices including ISS batteries on one flight.

World's First View of "Kibo" from HTV9 / HTV9 from "Kibo"

*All times are Japan Standard Time (JST. UTC + 9 hours)