en days after the United States pledged to give Russia $400 million for its cooperation in joint space operations, the head of the Russian space agency complained Tuesday that he wanted much more money."Of course it's not enough; I would have liked four times more," Yury Koptev told a press conference. "That doesn't mean we are not satisfied or that the Americans deceived us. It's just unfortunate that they are not buying more."Prime Minister Viktor Chernomyrdin and U.S. Vice President Al Gore signed the $400 million agreement on June 23, the latest in a series in recent years. It outlines joint cooperation in both nations' space-shuttle programs as well as on the initial design of a joint space station called Alpha.Russia has already received $28 million of those funds, and expects to get a total of $107 million before Oct. 1, said Koptev, who was formerly a top official in the Soviet state's military space program. The rest is expected to be paid before the end of 1997.The ultimate goal of the current cooperation is to build and maintain the Alpha space station, a $30 billion project which has been called the largest scientific collaboration ever. American astronauts and Russian cosmonauts will work aboard the craft after its scheduled 2001 maiden voyage.In a sign of growing U.S.-Russian space collaboration, Sergei Krikalev, a Russian cosmonaut, flew on the U.S. space shuttle Discovery in February. Two Americans are now training outside Moscow to fly aboard the Russian Mir station next year.