0715 GMT (2:15 a.m. EST)
A Japanese H-2A launcher blasted off from an idyllic island spaceport Tuesday, dispatching a daring six-year expedition to bring a piece of an asteroid back to Earth.

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0612 GMT (1:12 a.m. EST)
The Hayabusa 2 spacecraft is now flying on its own on the first leg of a six-year roundtrip journey to asteroid 1999 JU3. It arrives there in June 2018.

Meanwhile, three secondary payloads are scheduled to separate from the H-2A rocket's upper stage in the next few minutes. They include a student-built amateur radio satellite, a "deep space sculpture" conceived in a marriage of art and space exploration, and a suitcase-sized probe designed to fly by another asteroid in 2016.

0610 GMT (1:10 a.m. EST)
Hayabusa 2 separation!
0606 GMT (1:06 a.m. EST)
Deployment of Hayabusa 2 is moments away, but it may take a few minutes to confirm separation due to a gap in communications coverage from ground stations. A telemetry receiving station in Christmas Island will acquire signals from the rocket in a few minutes if separation can't be verified immediately.
0606 GMT (1:06 a.m. EST)
T+plus 1 hour, 44 minutes. The second stage engine has switched off again, and the rocket is preparing to deploy the Hayabusa 2 spacecraft in about 3 minutes.
0604 GMT (1:04 a.m. EST)
JAXA reports engine combustion, attitude control and the rocket's flight trajectory are normal. The H-2A rocket and Hayabusa 2 are 250 kilometers above Earth traveling at 8 kilometers per second.

This rocket burn is required to put Hayabusa 2 at the correct speed to break free of Earth's gravitational pull and travel into interplanetary space.

0602 GMT (1:02 a.m. EST)
T+plus 1 hour, 40 minutes. The H-2A rocket's LE-5B second stage engine is firing again. The engine consumes liquid oxygen and liquid hydrogen propellants, generating a maximum thrust of about 31,000 pounds.
0557 GMT (12:57 a.m. EST)
T+plus 95 minutes. Re-ignition of the second stage's LE-5B engine is less than 5 minutes away and will occur as the rocket crosses over Japan.

The burn will last about 4 minutes, 1 second.

0448 GMT (11:48 p.m. EST on Tues.)
T+plus 26 minutes. The H-2A rocket is coasting through space in a temporary low-altitude parking orbit. The upper stage's hydrogen-fueled LE-5B engine will ignite again at 0601 GMT (1:01 a.m. EST) for a four-minute burn to propel Hayabusa 2 free of the pull of Earth's gravity.

Separation of Hayabusa 2 is scheduled for 0609 GMT (1:09 a.m. EST), followed a few minutes later by release of three piggyback payloads carried on today's launch.

An H-2A rocket has never attempted such a lengthy coast period during any of the booster's 25 previous flights.

"In this launch of the H-2A rocket, we will execute a difficult operation called a long coast operation," said Hitoshi Kuninaka, JAXA's Hayabusa 2 project manager, in an interview with Spaceflight Now. "For most H-2A rocket launches, the satellite is separated about 30 minutes after the launch, but for this mission, we have a long coast operation and the H-2A rocket will do one orbit around Earth and when the rocket comes back over Japan, we will turn on the second stage engine again. We accelerate the spacecraft away from Earth and separate."

0433 GMT (11:33 p.m. EST on Tues.)
T+plus 11 minutes, 30 seconds. The second stage's LE-5B engine has cut off and the H-2A rocket has reached a parking orbit.

A second burn of the second stage engine is scheduled to begin at T+plus 1 hour, 39 minutes, 23 seconds.

0432 GMT (11:32 p.m. EST on Tues.)
T+plus 10 minutes. No problems have been reported thus far in the launch phase of the mission. The first cutoff of the second stage engine is scheduled for T+plus 11 minutes, 18 seconds.
0429 GMT (11:29 p.m. EST on Tues.)
T+plus 7 minutes. First stage main engine cutoff, staging and second stage ignition have all occurred on time, according to JAXA. Velocity is now about 5,200 meters per second and altitude is about 211 kilometers.

Rocketing east across the Pacific Ocean, the second stage LE-5B engine will fire for more than five minutes during this first burn of the mission to place the vehicle into a parking orbit.

A second burn will come later to put Hayabusa 2 on track to break free of Earth's gravity and escape into the solar system.

0426 GMT (11:26 p.m. EST on Tues.)
T+plus 4 minutes, 40 seconds. JAXA reports the four-meter-diameter payload fairing has been released from the rocket. The H-2A is now being powered by its LE-7A main engine at an altitude of 157 kilometers and a velocity of 2,800 meters per second.
0424 GMT (11:24 a.m. EST on Tues.)
T+plus 2 minutes. Burnout and separation of the twin solid rocket boosters that provided the bulk of thrust at liftoff. Altitude is now about 55 kilometers.
0423 GMT (11:23 p.m. EST on Tues.)
T+plus 60 seconds. The 17-story rocket has surpassed Mach 1 and is now experiencing the most extreme aerodynamic forces of its flight.
0422 GMT (11:22 p.m. EST on Tues.)
Liftoff of a Japanese H-2A rocket with Hayabusa 2, a daring expedition to return a piece of an asteroid to Earth.
0421 GMT (11:21 p.m. EST on Tues.)
T-minus 60 seconds and counting. Thousands of gallons of water are now being poured over the launch platform to cushion the structure from intense acoustic vibrations at launch. In the countdown's final minute, the rocket will be armed and the guidance system will start.

The ignition sequence of the first stage engine begins 5.2 seconds before liftoff. Solid rocket booster ignition occurs at T-zero.

0420 GMT (11:20 p.m. EST on Tues.)
T-minus 90 seconds. The first and second stage propellant systems have been readied for launch.
0419 GMT (11:19 p.m. EST on Tues.)
T-minus 3 minutes. The H-2A rocket has switched to internal power.
0417 GMT (11:17 p.m. EST on Tues.)
T-minus 4 minutes, 30 seconds. The automatic countdown sequence has started and the H-2A rocket's propellant tanks will soon be pressurized for flight.
0417 GMT (11:17 p.m. EST on Tues.)
T-minus 5 minutes. The Hayabusa 2 payload is reported ready for launch.
0416 GMT (11:16 p.m. EST on Tues.)
T-minus 5 minutes, 30 seconds. The weather is acceptable for launch today, according to JAXA.
0415 GMT (11:15 p.m. EST on Tues.)
T-minus 7 minutes. The range safety system is reported ready for launch.
0412 GMT (11:12 p.m. EST on Tues.)
T-minus 10 minutes. The Hayabusa 2 spacecraft should soon be operating on internal battery power as the satellite and launcher are configured for liftoff at 0422:04 GMT (11:22:04 p.m. EST).
0410 GMT (11:10 p.m. EST on Tues.)
T-minus 12 minutes. In the final minutes of the countdown, an automated sequencer will control the final crucial steps before launch.

The automatic sequence will begin at T-minus 4 minutes, 30 seconds and computers will pressurize the H-2A's propellant tanks for flight at about T-minus 4 minutes, 20 seconds.

At about T-minus 3 minutes, the launcher will transition to internal battery power and remove external power.

Water will be released onto the launch pad deck beginning at T-minus 73 seconds to help suppress sound and acoustics during the ignition and liftoff. The vehicle's pyrotechnic and ordnance systems will be armed at T-minus 30 seconds and the rocket's guidance system initializes at T-minus 18 seconds. Batteries controlling solid rocket booster ignition are activated at T-minus 15 seconds.

Sparklers underneath the rocket's main engine ignite at T-minus 11.7 seconds to burn off residual hydrogen that could be an explosive hazard at main engine start.

0402 GMT (11:02 p.m. EST on Tues.)
T-minus 20 minutes. Engineers are uploading the latest upper level wind data into the H-2A's flight computer. The rocket will use the information to compute a specific steering profile based on the real launch day weather conditions.

At liftoff, the H-2A will be propelled upward from the launch pad on the power of a single hydrogen-burning LE-7A main engine and two solid rocket motors. The total liftoff thrust of the rocket is approximately 1.6 million force pounds.

The rocket will pitch southeast from Tanegashima, racing through the speed of sound in less than a minute and reaching an altitude of more than 30 miles in the first two minutes of flight.

After consuming their pre-packed solid propellant, the two strap-on boosters will jettison at about the two-minute point. The 13.1-foot diameter payload shroud will separate at T+plus 4 minutes, 10 seconds after the H-2A rocket ascends above the discernable traces of Earth's atmosphere.

First stage main engine cutoff, stage separation and ignition of the second stage's LE-5B engine will occur nearly seven minutes into the mission. The second stage will burn for more than five minutes before shutting down at T+plus 11 minutes, 18 seconds.

After a nearly 90-minute coast, the second stage will reignite for a 4-minute, 1-second burn.

Deployment of the Hayabusa 2 spacecraft is expected at T+plus 1 hour, 47 minutes, 15 seconds.

Three secondary payloads -- Procyon, Shin'en 2 and Artsat 2 -- will separate from the H-2A rocket a few minutes later.

0342 GMT (10:42 p.m. EST on Tues.)
Some statistics on today's launch:
0322 GMT (10:22 p.m. EST on Tues.)
Now 60 minutes from the planned launch of the H-2A rocket.

Officials just gave the "go" to enter the terminal count, which began at 0322 GMT. The final hour of the countdown will prepare the rocket, the payloads, and ground systems for flight.

The H-2A rocket for today's launch is flying in the "202" configuration with two large 15-meter-long (49-foot) solid rocket boosters and without any of the smaller strap-on boosters sometimes used to augment the launcher's thrust.

It also features a standard four-meter (13.1-foot) diameter nose shroud, which encloses the Hayabusa 2 spacecraft for the first few minutes of flight through the lower atmosphere.

Japanese engineers added thermal paint to a section of the rocket's upper stage for today's launch, which will mark the first time the rocket will fly a lengthy hour-and-a-half coast phase before restarting the second stage engine.

The long coast is necessary to inject Hayabusa 2 on the proper trajectory.

The lead contractor for the H-2A rocket is Mitsubishi Heavy Industries.

0308 GMT (10:08 p.m. EST on Tues.)
There are 75 minutes left in today's countdown before liftoff of the H-2A rocket with Hayabusa 2, the most ambitious asteroid exploration mission ever attempted.

Hayabusa 2 weighs about 600 kilograms, or approximately 1,320 pounds, at the time of launch. It was built by NEC Corp. of Japan.

The spacecraft will be deployed on a trajectory into deep space to begin a six-year mission to gather samples from a distant asteroid and return the material to Earth.

Hayabusa 2 will fly by Earth again in December 2015 to receive a speed boost from Earth's gravity. The probe will reach asteroid 1999 JU3 in June 2018 for one-and-a-half years of detailed study.

During its stay near the asteroid, the spacecraft will conduct a series of touch-and-go maneuvers to collect bits of rock and dust from its surface. It will also release four landers -- three from Japan and one from Europe -- to bounce around the asteroid, take pictures, and provide ground truth for the Hayabusa 2 mothership's observations.

Hayabusa 2 will leave the asteroid in December 2019 and return to Earth in December 2020, when scientists will recover the samples for analyses in laboratories.

Asteroid 1999 JU3 is about six-tenths of a mile across and completes one rotation every seven hours and 38 minutes. Scientists believe the object is a "C-type" asteroid rich in carbon, organic molecules and water.

0255 GMT (9:55 p.m. EST on Tues.)
A second steering check of the rocket's engines has been accomplished, according to Mitsubishi Heavy Industries.

Another "go/no go" decision point is coming up soon, before the countdown enters the terminal phase at T-minus 60 minutes.

The Hayabusa 2 spacecraft is heading for an interplanetary journey. The H-2A rocket's upper stage LE-5B engine will fire two times to accelerate the probe to escape the grasp of Earth's gravity.

0010 GMT (7:10 p.m. EST on Tues.)
Radio checks have been completed between the rocket and ground stations.
2330 GMT (6:30 p.m. EST)
Mitsubishi Heavy Industries, the H-2A rocket's contractor and commercial operator, reports the liquid hydrogen and liquid oxygen tanks aboard the launcher are now full of super-cold cryogenic propellant.

The next few hours of the countdown will be spent activating and checking out a variety of rocket systems, including radio frequency links with tracking stations. Another steering check of the rocket's main engine is also planned.

After testing is completed, officials will give the go-ahead for the terminal countdown scheduled to start at 0322 GMT. Liftoff remains set for 0422 GMT (11:22 p.m. EST), or 1:22 p.m. local time at the Tanegashima Space Center in southern Japan.

2145 GMT (4:45 p.m. EST)
Slew checks of the H-2A rocket's first stage engine have been completed, verifying the powerplant will be able to steer the launcher during ascent.
2020 GMT (3:20 p.m. EST)
Safety officials have established road blocks 400 meters from Launch Pad No. 1 of the Yoshinobu launch complex. The Yoshinobu launch complex was built for the H-2 rocket program that began operations in 1994 and has since been modified for use by the more powerful and H-2A rocket family.

The pads are positioned on a rocky outcrop on the southeastern flank of Tanegashima Island, which lies about 80 miles south of Kagoshima, Japan.

The complex features two pads for the H-2A and H-2B rockets. Launch Pad No. 2 has been used for four flights of the H-2B rocket with the H-2 Transfer Vehicle, an unmanned cargo ship for the International Space Station. In all, 36 rockets have departed Earth from the Yoshinobu complex since 1994. The most recent flight was an H-2A rocket launch in October 2014.

1945 GMT (2:45 p.m. EST)
Launch officials report they are go for cryogenic fueling of the H-2A rocket. The launcher's two stages consume liquid hydrogen and liquid oxygen propellants. Two strap-on boosters attached to the first stage are already packed with solid fuel.

The LE-7A and LE-5B engines on each stage burn the super-cold propellants during the flight. Because the propellant is stored under cryogenic conditions, it must be gradually replenished throughout the countdown to ensure proper levels of fuel are inside the rocket at liftoff.

1630 GMT (11:30 a.m. EST)
The orange, black and white H-2A rocket has arrived at Launch Pad No. 1 at Tanegashima's Yoshinobu launch complex to begin preparations for fueling, including the connection of fuel lines and data and electrical cables between the ground complex and the rocket.

The 500-meter rollout from the Vehicle Assembly Building occurs about 12 hours before liftoff. The trip follows rail tracks and takes about a half-hour to complete.

JAXA and Mitsubishi Heavy Industries, the H-2A rocket's prime contractor, report all systems are functioning well at this point in the countdown.

Japan's H-2A rocket is set to leave its assembly building at the Tanegashima Space Center on Tuesday for a half-hour rollout to its seaside launch complex for final countdown preparations.

The 17-story rocket is set for liftoff at 0422:04 GMT Wednesday (11:22:04 p.m. EST Tuesday) with Hayabusa 2, a robotic spacecraft embarking on a six-year roundtrip journey to collect samples from and asteroid and return the materials to Earth.

Fitted with two solid-fueled boosters and hydrogen-burning first stage and second stage engines, the H-2A launcher will roll out on rails to Launch Pad No. 1 at Tanegashima. Rollout is expected about 12 hours before liftoff.

The launch base is located on Tanegashima Island, which lies off the southern coast of Kyushu at the southwest end of the Japanese main islands.

Once the rocket arrives at the launch pad, technicians will connect the vehicle to the facility's electrical and propellant supplies before fueling of the launcher with liquid hydrogen and liquid oxygen.

Poor weather at the Tanegashima Space Center in Japan has grounded until at least Wednesday the launch of a $300 million robotic mission to fly to an asteroid, pick up samples and return them to Earth.

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