They keep me going at 400 kilometers above Earth
Essential supplies (including treats I never imagined, like green tea and chestnut jelly cakes) are delivered to my home way away from home—the International Space Station (ISS)—by the H-II Transfer Vehicle. Mitsubishi Electric’s autonomous orbit control technology helps the vehicle rendezvous safely with the Space Station every time. Even at 28,800 km/hour, Mitsubishi Electric works for me.
–American astronaut on the ISS
What is HTV?
The HTV* is the first Japan-made unmanned, automated vehicle for delivering supplies to the International Space Station (ISS)
*HTV: H-II Transfer Vehicle
Images of ISS and HTV provided by JAXA
Sophisticated control technology ensures a safe, on-target rendezvous.
Home to Japan's Kibo Laboratory and other facilities, the International Space Station (ISS) orbits at an altitude of 400 km and circles Earth at a speed of 8km per second. The unmanned HTV supply vehicle autonomously delivers food, replacement parts, test equipment, and other items to the crew living on the ISS. This vehicle's "brain" -- its Avionics Module--was developed by Mitsubishi Electric. Current plans call for the launch of six more HTV’s in addition to the HTV-1, which has already completed its mission. Delivering food and clothing to space is one small step for humanity. But it is a giant leap towards the dream of human advances in space.
Advanced autonomous control technology
The difficulty in completing a rendezvous with the ISS comes from the way HTV approaches the ISS: not from behind but from underneath (inner orbit). The reason for approaching from underneath is to protect the ISS in the unlikely event of a problem. However, to move toward the ISS from an inner orbit and maneuver to within 10 meters of it requires advanced autonomous control technology.
The HTV uses sophisticated technologies for navigational guidance control, communications, data processing and power supply. These key Mitsubishi Electric technologies were developed from successful rendezvous and docking experiments made in 1998 with the Orihime and Hikoboshi satellites.
Extreme reliability and safety
For the unmanned, automated HTV to safely rendezvous with the manned ISS, an unprecedented level of reliability exceeding that of previous satellites is required. Not only is each and every part made to be extremely durable, but if a failure occurs, the vehicle can also diagnose and correct itself. Even if two failures occur simultaneously, the HTV is designed to automatically avoid damaging the ISS.
Fail Safe & One-Fail Operative
Comparison chart of fail safe and one-fail operative function