Japan’s Kounotori 6 cargo carrier will get a boost from a powerful H-2B rocket to send the supply ship and its 4.5 tons of provisions and experiments on a four-day pursuit of the International Space Station.
The sixth H-2 Transfer Vehicle is set for liftoff at 1326 GMT (8:26 a.m. EST; 10:26 p.m. Japan Standard Time) Friday in an instantaneous launch opportunity to catch up with the space station.
The two-stage, 186-foot-tall (56-meter) H-2B rocket is Japan’s most capable launcher. It is an upgrade from the Japanese H-2A rocket.
The H-2B features two LE-7A first stage engines instead of one, four solid rocket boosters instead of the two normally aboard H-2A missions, and a first stage with a diameter of nearly 17.1 feet (5.2 meters), an increase from the 13.1-foot-wide (4-meter) core of the H-2A rocket. The H-2B’s first stage is also more than 3 feet — about 1 meter — longer than the H-2A’s first stage.
That allows the H-2B rocket to carry 1.7 times the liquid hydrogen and liquid oxygen propellants that can be flown on the H-2A, effectively doubling the heavier launcher’s lift capacity.
After liftoff, the H-2B will turn southeast over the Pacific Ocean, aligning with the International Space Station’s flight path. It will take about 15 minutes for the rocket to deliver the Kounotori 6 spacecraft to an initial orbit, kicking off its chase of the research complex.
Cosmonauts Sergey Prokopyev and Dmitri Petelin floated outside the International Space Station Wednesday, unbolted an experiment airlock from the Rassvet docking compartment and then connected it to Russia’s Nauka multi-purpose laboratory module in a 7-hour, 11-minute excursion.
Russian ground controllers decided Tuesday to delay the docking of a Progress supply freighter to the International Space Station until Thursday after telemetry signals indicated two radar navigation antennas may not have deployed following the ship’s launch from Kazakhstan.
NASA and SpaceX have set April 22 as the target launch date for the next Crew Dragon flight to the International Space Station. The four-person crew will be the first to ride a previously-flown Falcon 9 booster and a reused Dragon spacecraft, and a NASA official said this week that the launcher and capsule are in “really good shape” as refurbishment wraps up at Cape Canaveral.