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.
The MS-25 mission was scrubbed on Thursday, but the root cause is still under investigation. The earliest that liftoff from the Baikonur Cosmodrome can now occur is Saturday, March 23, pending the outcome of the investigation.
Less than a week after winding up a successful spacewalk, outgoing space station commander Jeff Williams, America’s most experienced astronaut, will join two Russian cosmonauts for a fiery descent to Earth Tuesday evening to close out a 172-day mission covering 2,752 orbits and 72.8 million miles since launch last March.
Bigelow Space Operations says it will charge $52 million per seat to send private astronauts to the International Space Station aboard Crew Dragon ferry ships, and has already paid “substantial sums” to SpaceX for up to four dedicated crew missions to the orbiting research complex.