The science and technology ministry plans to launch sometime in fiscal 2008 a rocket that can carry a payload 50 percent larger than the current H-IIA rocket.

The successor to Japan's principal rocket is the H-IIB, a heavy-lift version that will be able to carry up to 8 tons of satellites and other vehicles into space, ministry officials said. The H-IIA's payload capacity is between 4 and 6 tons.

Its main mission is to carry the H-2 Transfer Vehicle to the International Space Station without relying on the U.S. space shuttles. The HTV will carry food, clothes and scientific equipment to the station.

The main body of the H-IIB will be around 1 meter greater in diameter and have two engines -- one more than the H-IIA -- as well as four solid-fuel boosters, according to officials at the Education, Culture, Sports, Science and Technology Ministry.

The No. 1 and No. 2 vehicles of the new rocket are projected to be launched in fiscal 2008 from the Tanegashima Space Center in Kagoshima Prefecture, and the ministry is hoping to have the No. 2 unit carry the first HTV, the officials said.

The Japan Aerospace Exploration Agency and Mitsubishi Heavy Industries Ltd. have been developing the new rocket since 2004 on a budget of around 20 billion yen.

For fiscal 2006, the ministry is seeking around 3.8 billion yen for the H-IIB.

In February, Japan's seventh H-IIA rocket successfully placed a multipurpose weather and navigation satellite into orbit -- 15 months after the previous launch ended in failure.