An interplanetary weather satellite bound for Venus and a device to test new propulsion techniques were trucked across Japan's island space center Sunday to meet the H-2A rocket that will launch the payloads into space next week.

The H-2A rocket payload fairing containing Akatsuki and Ikaros was transported to the Vehicle Assembly Building over the weekend. Credit: JAXA

Cocooned inside the launcher's nose shroud, the payloads were loaded onto a trailer and driven less than a mile from a checkout facility to the Vehicle Assembly Building at the Tanegashima Space Center's Yoshinobu launch complex.

Once inside the VAB, the nearly 40-foot-tall fairing was lifted atop the H-2A rocket and firmly bolted to the booster.

After engineers complete testing of the rocket, the 17-story vehicle will roll on rail tracks about 1,500 feet to the launch pad next Monday. Once the rocket arrives at the launch pad, workers will load liquid hydrogen and liquid oxygen propellant into the H-2A's first and second stages.

Flying for the 17th time, the H-2A rocket on this mission carries a pair of powerful solid rocket boosters and no smaller strap-on motors. This configuration is called the "202" version.

Akatsuki was lowered onto the payload adapter in late April. Credit: JAXA

Liftoff is scheduled for exactly 2144:14 GMT (5:44:14 p.m. EDT) Monday from Launch Pad No. 1 at Tanegashima. The rocket must launch at a precise instant each day to reach the trajectory toward Venus.

The launch will occur at 6:44 a.m. local time at Tanegashima, a narrow strip of land off the coast of Japan's Kyushu Island, the southernmost of the country's four largest land masses.

About the size of a small car, the Akatsuki spacecraft arrived at the launch site March 19 to begin final testing and fueling operations. The Ikaros solar sail, a secondary payload, was shipped to Tanegashima in early April.

The 1,100-pound Venus probe was attached to an apparatus containing Ikaros and other small satellites April 30. The payloads were encapsulated inside the fairing May 4.

The payloads were shrouded inside the rocket's nose cone May 4. Credit: JAXA

Akatsuki should reach Venus by December if it gets off the ground during a planetary window stretching between May and June. Akatsuki will carry six instruments to study the Venusian atmosphere from its outer boundary with space to the planet's hellish surface.

The probe will enter an equatorial orbit around Venus stretching from just above the planet's blanketing atmosphere to an altitude of nearly 50,000 miles. It will be ideally placed to observe the whipping winds that drive massive storm systems in the Venusian atmosphere.

Ikaros will be released on the same course as Akatsuki, but its mission will be to demonstrate applying light pressure from the sun as a source of interplanetary propulsion. Although never before tested in deep space, solar sails could provide efficient propulsion for future missions traveling between planets and stars.