A Japanese satellite equipped with a sharp-eyed synthetic aperture radar launched Saturday on a mission to map the globe every two weeks, helping authorities respond to natural disasters, track agricultural yields and monitor shipping lanes.

Read our full story.

Four small secondary payloads built by Japanese universities and industry are also slated to be released from the H-2A rocket's second stage in the next few minutes. They include Rising 2, Uniform 1, Socrates and SPROUT.

In the next few minutes, the spacecraft is expected to deploy its solar panels spanning 54 feet tip-to-tip to begin charging its batteries. Deployment of the ALOS 2 satellite's radar antenna will begin about 13 hours after launch in a three-step process extending into Sunday.

ALOS 2 separation! JAXA has confirmed the spacecraft has been deployed into the planned orbit.

T+plus 15 minutes, 25 seconds. The second stage's LE-5B engine has cut off and the H-2A rocket should now be in orbit. Deployment of the ALOS 2 spacecraft is moments away.

T+plus 10 minutes. No problems have been reported thus far in the launch phase of the mission. Second stage cutoff is scheduled for T+plus 15 minutes, 14 seconds.

T+plus 7 minutes, 20 seconds. First stage main engine cutoff, staging and second stage ignition have all occurred on time, according to JAXA. Velocity is now about 3,100 meters per second.

The second stage LE-5B engine will fire for more than eight minutes during this first burn of the mission to place the vehicle into low Earth orbit.

The rocket initially flew southeast from Tanegashima to avoid flying over populated islands. It is now turning south to inject ALOS 2 in the correct orbit at an inclination of 97.9 degrees.

T+plus 4 minutes, 45 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 1,800 meters per second.

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.

T+plus 60 seconds. The 17-story rocket has surpassed Mach 1 and is now experiencing the most extreme aerodynamic forces of its flight.

Liftoff of a Japanese H-2A rocket with ALOS 2, a satellite with radar vision to map the world every 14 days.

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 ignitions occurs at T-zero.

T-minus 90 seconds. The first and second stage propellant systems have been readied for launch.

T-minus 3 minutes. The H-2A rocket has switched to internal power.

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.

T-minus 5 minutes. The ALOS 2 payload is reported ready for launch.

T-minus 5 minutes, 30 seconds. The weather is acceptable for launch today, according to JAXA. The current conditions are a temperature of 76 degrees Fahrenheit and east winds of about 12 mph.

T-minus 7 minutes. The range safety system is reported ready for launch.

T-minus 10 minutes. The ALOS 2 spacecraft should soon be operating on internal battery power as the satellite and launcher are configured for liftoff at 0305 GMT (11:05 p.m. EDT).

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.

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, 30 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 eight minutes before shutting down at T+plus 15 minutes, 14 seconds.

Deployment of the ALOS 2 satellite is expected at T+plus 16 minutes, 4 seconds. ALOS 2 will begin extending its solar panels a few minutes after spacecraft separation.

Four other small satellites will be released through the T+plus 37 minute point.

Some statistics on today's launch:

• 24th H-2A launch since 2001
• 35th H-2 family launch since 1994
• 13th launch of the H-2A (202) configuration
• 2nd launch from Tanegashima in 2014
• 30th space launch attempt worldwide in 2014

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 0205 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 ALOS 2 spacecraft for the first few minutes of flight through the lower atmosphere.

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

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 ALOS 2 spacecraft is heading for an orbit about 628 kilometers, or 390 miles, in altitude with an inclination of 97.9 degrees.

There are two hours left in today's countdown before liftoff of the H-2A rocket with the Advanced Land Observing Satellite 2, radar-equipped Earth observing spacecraft built as a follow-up to a spacecraft which failed in 2011 after a five-year mission.

GPM weighs about 2.1 metric tons, or approximately 4,600 pounds, at the time of launch. It was built by Mitsubishi Electric Co. in Japan.

The spacecraft is fitted with one primary instrument -- the PALSAR 2 L-band synthetic aperture radar.

ALOS 2 is also called Daichi 2. Daichi is the Japanese word for land.

The new mission can spot smaller surface features and has a wider observing area than its predecessor. Instead of taking 46 days to revisit the same location on Earth, as was the case with the first ALOS mission, the ALOS 2 spacecraft will fly over the same spot every two weeks.

The L-band radar also has a top resolution between 1 and 3 meters (3.3 feet to 9.8 feet), meaning it can see objects as small as shipping vessels, trucks and homes.

Officials plan to use ALOS 2 data in applications including disaster and emergency response, climate change monitoring, tracking deforestation, and locating ships and sea ice for security authorities.

Japan says it will share ALOS 2 imagery globally under an agreement signed with international governments.

Check out photos of the rollout of the H-2A rocket to the launch pad a few hours ago.

See the launch timeline for details on the H-2A rocket's ascent into orbit with the Advanced Land Observing Satellite 2.

We have also posted a cutaway diagram of the H-2A launch vehicle.

Radio checks have been completed between the rocket and ground stations.

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 0205 GMT. Liftoff remains set for 0305 GMT (11:05 p.m. EDT), or 12:05 p.m. local time at the Tanegashima Space Center in southern Japan.

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.

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, 34 rockets have departed Earth from the Yoshinobu complex since 1994. The most recent flight was an H-2A rocket launch in February 2014.

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.

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

An advanced radar mapping satellite is on the launch pad awaiting liftoff Saturday aboard a Japanese H-2A rocket to begin at least a five-year mission collecting high-resolution all-weather images of Earth from nearly 400 miles up.

The Advanced Land Observing Satellite 2 is set for launch at 0305:14 GMT Saturday (11:05:14 p.m. EDT on Friday) from the Tanegashima Space Center in southwestern Japan.

The 15-minute launch window opens at 12:05 p.m. Japan Standard Time on Saturday.

Fitted with two strap-on solid rocket motors to provide an extra boost, the H-2A's hydrogen-fueled first and second stage engines will propel the 2.3-ton ALOS 2 satellite into orbit at an altitude of 390 miles, or 628 kilometers, and an inclination of 97.9 degrees.

The 174-foot-tall H-2A launcher, making its 24th flight since 2001, will first fly southeast from Tanegashima to prevent flying over populated islands, then turn south to put ALOS 2 and four small secondary payloads into orbit.

The orange, black and white rocket just 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 half-hour rollout occurs about 12 hours before liftoff.

The ALOS 2 spacecraft, manufactured by Mitsubishi Electric Co., is a follow-on mission to the first ALOS satellite launched in 2006. ALOS failed in orbit in May 2011, just after returning vital data in the aftermath of the 2011 earthquake and tsunami that ravaged the coast of northern Japan.

Officials say ALOS 2 will supply imagery to help respond to man-made and natural disasters, monitor the environment, track food yields and crop production, study volcanoes and earthquakes, and manage forests.

The mission is supposed to last five years, with a target of seven years of operations.

ALOS 2 is shrouded inside the H-2A rocket's 13.1-foot-diameter payload fairing for the ride into space Saturday.

Separation of the spacecraft from the rocket's upper stage is expected about 16 minutes after liftoff.

Within the first half-hour of the mission, ALOS 2 will deploy its two solar array wings to begin generating electricity. The three-step process to unfurl the satellite's radar antenna begins about 13 hours after launch, ending with the final deployment some time Sunday.

The L-band synthetic aperture radar antenna, known as PALSAR 2, will see objects on the ground as small as 3 meters, or about 10 feet. That is an improvement from the ALOS mission's radar, which had a top resolution of 10 meters, or about 33 feet.

The upgrades to ALOS 2 also include a faster revisit time. It can image the same location on Earth every two weeks, while ALOS could only do that every 46 days.

When fast-paced events like natural disasters need monitoring, ALOS 2 will offer better responsiveness to emergency managers, officials said.

Besides using ALOS 2 for their own needs, the Japanese government will share the data with other governments and global partners under international agreements.