The Japan Aerospace Exploration Agency (JAXA) will launch a cargo of experiments, supplies and small satellite payloads to the International Space Station today at 12:05 PM EDT (1:05 AM JST / 9:05 AM PDT). The payload will be delivered via a Mitsubishi Heavy Industries (MHI) H-IIB rocket, packed in an H-II Transport Vehicle (HTV) unpiloted cargo spacecraft, which will then rendezvous with the ISS to offload science experiments and new lithium-ion batteries for use in replacing older nickel-hydrogen ones used on the orbital laboratory.
This mission is codenamed “HTV-8,” the eighth mission that MHI has run using the HTV cargo ship. It’ll launch from Tanegashima Space Center in Japan, which is on a small island off the very southern end of Japan’s Kyushu region. This is the second attempt for the launch, after the original try was scrubbed prior to lift-off due to a small fire on the launch pad, which MHI subsequently investigated and corrected.
The H-IIB rocket is a fully expendable launch vehicle, with a liquid-oxygen-fueled central core and four solid fuel boosters that surround the base to provide more lift, giving the rocket a total lift capacity of up to 18,000 lbs to geostationary transfer orbit, or as much as 36,400 lbs to low Earth orbit.
This eighth flight for the H-IIB will also be its second to last — the company plans one more flight for this configuration before focusing entirely on its forthcoming H3 medium-lift launch vehicle, which will boost cargo capacity to as much as 14,300 lbs to geostationary transfer orbit, and which will reduce launch costs by more than half, to between $50-$65 million, in an effort to become more price competitive with emerging commercial launch providers like SpaceX. H3 is targeting next year for its first test flights, with commercial operations kicking off in 2021.
NASA will begin broadcasting the live stream of the launch above starting at around 11:30 AM EDT (8:30 AM PDT).