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H-2B launch timeline
Posted: July 19, 2012

T-00:00 Liftoff
With its two LE-7A main engines and four solid rocket boosters firing, the 186-foot-tall H-2B rocket lifts off from the Yoshinobu launch complex on Tanegashima Island. A few moments later, the rocket will complete a pitch program to head southeast from the launch site.
T+01:54 SRB-A Burnout
The H-2B's four solid rocket boosters exhaust their propellant and burn out at an altitude of 33 miles.
T+02:04 SRB-A 1st Pair Separation
The first pair of the four solid rocket boosters is jettisoned.
T+02:07 SRB-A 2nd Pair Separation
The second pair of the four solid rocket boosters is jettisoned 39 miles in altitude and 42 miles downrange.
T+03:40 Fairing Separation
After traversing the dense lower atmosphere and reaching an altitude of 75 miles, the rocket releases the 5-meter (16.4-foot) diameter payload fairing protecting the H-2 Transfer Vehicle during the early part of the flight.
T+05:47 Main Engine Cutoff
After consuming its liquid hydrogen and liquid oxygen propellants, the twin LE-7A first stage main engines are shut down. The first stage and solid rocket boosters push the rocket to a velocity of about 12,500 mph.
T+05:54 Stage Separation
The H-2B rocket's first stage is separated now, having completed its job, jettisoning at 117 miles in altitude and 464 miles downrange. The spent stage will fall into the Pacific Ocean.
T+06:01 Second Stage Ignition
With the first stage jettisoned, the rocket's second stage takes over. The LE-5B hydrogen-fueled engine ignites at an altitude of 121 miles to accelerate the H-2 Transfer Vehicle to orbital velocity.
T+14:20 Second Stage Cutoff
The LE-5B second stage engine shuts down after reaching its specified orbital targets. This completes the powered phase of the launch at an altitude of 180 miles and 2,314 miles downrange from the pad.
T+15:11 HTV Separation
The 35,000-pound H-2 Transfer Vehicle is deployed on its way to the International Space Station, wrapping up the flight of the H-2B rocket. Spacecraft separation will occur off the northeast coast of New Guinea. The launcher is targeting an orbit with a high point of 300 kilometers (186 miles), a low point of 200 kilometers (124 miles), and an inclination of 51.6 degrees.

Data Source: JAXA