This "back-up" agreement would enable a client of one of the three firms to call on either of the other two to launch a satellite in the case of technical problems, explained Arianespace chief executive Jean-Yves Le Gall.

Arianespace was negotiating a similar agreement with the Japanese government covering public satellites, Le Gall told a news conference in Tokyo.

Until now, the launch contractor has provided a replacement when it fails in a rocket launch, causing a delay and trouble for customers.

"Arianespace and NASDA (National Space Development Agency of Japan) are discussing how it would be possible to implement such a back-up agreement," Le Gall said.

"We are also looking at the possiblity for a back-up agreement for commercial launches," he continued, referring to the possible tie-up between his firm, Boeing and MHI.

"I hope next time I will be in Japan next fall I will be in a position to announce formally the agreements I just mentioned."

At present MHI only launches public satellites, a company spokesman said.

"We are not in a position to comment" on the subject of this possible accord, he said.

The Asahi newspaper said last month the rockets to be covered by the scheme would be the H2-A built by MHI, Ariane-5 by the European consortium and Boeing's Sea-Launch.

Arianespace has been the world's number one satellite launcher for 20 years, declared Le Gall, who is visiting Japan to take part in a symposium on French-Japanese cooperation in space.

The European firm has launched 212 satellites. It has enjoyed 60 percent of the global market for the past 15 years, said Arianespace senior vice president of sales marketing and programs Philippe Berterottiere.

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