Japan launches historic MMX sample-return mission to Mars' moon Phobos (video)

Japan's groundbreaking mission to Mars is officially underway, headed to the Red Planet's mysterious moons Phobos and Deimos for a historic sample-return attempt.

The Martian Moons eXploration (MMX) mission launched today (Oct.

19) from Tanegashima Space Center in Japan, riding an H3 rocket that lifted off from Pad-2 at Tanegashima's Yoshinobu Launch Complex at 3:41 p.m.

EDT (1941 GMT; 4:41 a.m. local time in Japan on Oct.

20).

The JAXA ( Japan Aerospace Exploration Agency )-led MMX mission is bound for Mars orbit, where it will study the planet's two moons, Phobos and Deimos.

If everything goes according to plan, MMX will become the first spacecraft to land on and return samples from Phobos for study back on Earth, which scientists think could shed light on a decades-old mystery about the moons' origins and reveal clues about the formation of the early solar system .

It was the 10th liftoff of Japan's expendable, two-stage H3 rocket, which was jointly developed by JAXA and Mitsubishi Heavy Industries.

After clearing its launch pad today, the 207-foot-tall (63 meters) launch vehicle flew a nominal trajectory through its ascent corridor over the Pacific Ocean, jettisoning its four solid boosters in pairs just before the flight clock reached two minutes.

The rocket shed its payload fairings about one minute and 20 seconds later, exposing MMX to the vacuum of space for the first time.

H3's first stage is powered by two LE-9 rocket engines, channeling a mixture of liquid hydrogen and liquid oxygen to produce a combined thrust of 331,000 pounds (1,471 kN), according to Mitsubishi Heavy Industries.

As the mission clock approached T+5 minutes, H3 executed its main engine cut off procedure and separated from the second stage, which ignited its engines for a 5.5-minute burn about 10 seconds later.

If all goes according to plan, the H3 upper stage will ignite its engine for a second time for a trans-Mars injection burn about one hour and four minutes after liftoff, a maneuver that will last roughly six minutes and 25 seconds.

MMX will be released from the rocket's upper stage about one minute after the completion of that burn, while flying approximately 368 miles (592 kilometers) above central Africa.