"We exploded the rocket because it swayed off orbit," confirmed an official at the National Space Development Agency (NASDA)'s Tanegashima Space Center in southern Japan.

Yuji Sato, a spokesman at the center, said "the main engine stopped some four minutes after liftoff," which took place at the space centre at 4:29 p.m. (0729 GMT).

"We still do not know the reason it stopped and will have to analyze flight data which are coming up now," Sato said.

Prime Minister Keizo Obuchi said he was "a bit worried" about the costly H-2 rocket project, noting it was the second successive failure after a February 1998 flop.

"I think it was very regrettable and I have ordered a thorough investigation," he was quoted as telling an executive meeting of his party in Tokyo.

The two-stage, liquid-fuel propulsion H-2 rocket cost 14 billion yen and the satellite, which had been destined for weather forecasting and air traffic control, another 10 billion yen.

Crew at the ground center "exploded the rocket about 500 seconds after the launch," as it was going out of control, Sato said. The pieces were now believed to be in the Pacific.

NASDA executive director Eiji Sogame said the main engine, located in the first stage, had never caused trouble before.

"It was a problem we had never anticipated," Sogame told a news conference in Tanegashima.

Hirofumi Nakasone, chief of the Science and Technology Agency, vowed to "make the utmost effort to investigate the cause thoroughly and take measures."

Transport Minister Yoshihiro Nikai said he hoped Japan would be able to carry out another launch "at the earliest possible time."

The failed launch, which had been repeatedly delayed for fuel sensor and other problems, was a devastating blow to Japan's home-grown H-2 rocket program which had been trying to recover its shattered reputation.

In the last H-2 launch in February 1998, a 36-million-dollar satellite was lost in space despite a successful separation from the rocket because it was released at the wrong altitude and sent into an elliptical orbit.

Japanese press described that satellite as "million dollar garbage."

The latest launch was the seventh blast-off since 1994 of the Japanese H-2 rocket, supposed to be a fully-Japanese built rival to the successful European Ariane-4.

NASDA is now developing the H-2-A rocket, a high-performance but cheaper version of the H-2, for an expected launch in 2000 but experts have warned it could be delayed.

A report by the Nikkei Weekly said the latest launch was critical to Japan's space reputation.

"For Japanese rockets to gain credibility in the world market the minimum requirement would be a successful launch of the H-2 rocket," the newspaper said before the disaster.

"This would speed the commercialization of the H-2-A."

The Nikkei Weekly listed a catalogue of problems ahead of the launch, including a cable intalled by Mitsubishi Heavy Industries Ltd. which fell off and damaged the outer covering.

"Then a design problem was discovered with batteries in control units for engines which delayed the launch for more than three months."

H2 #8 Flight Sequence
Weather: Fine Wind: North North East 7.7 m/s Temp: 22.5C
Event 1. lift off - 16.29 (JST) 2. SRB burn out 3. SRB separation 4. Fairing jettison 5. Main Engine Cutoff 6. Second stage separation 7. Second stage ignition 8. All systems off 9. destruct command sent	actual time 16.29 (JST) 1:31 1:37 4:50 3:59 5:22 5:30 7:35 7:41	flight plan 16.29 (JST) 1:34 1:37 4:15 5:36 5:54 6:00 n/a n/a
Note: time given are mins/secs after launch