The recently resigned head of Soviet space research says his country's maiden space shuttle launch had "absolutely no scientific value," and the U.S. and Soviet shuttle programs are in "deep trouble" economically.

Roald Z. Sagdeev, who headed the Soviet Space Research Institute for 15 years, said last week's inaugural Soviet shuttle flight - like the 1981 flight of the first U.S. shuttle - was an "outstanding technological achievement."The shuttle, however, "is technology of the 21st century. Why should we pay 20th-century money for it?"

"My personal view is that American experience with the shuttle indicates that from the point of view of cost efficiency, the shuttle is in deep trouble," said Sagdeev, who has followed closely the U.S. decision-making process on the shuttle and is a key science and arms control adviser to President Mikhail S. Gorbachev.

"It is much simpler and cheaper to fly a payload with any kind of expendable vehicle."

Sagdeev, like many American scientists, fears the costly shuttles are drawing away much needed funds from basic science, and that manned flight is unnecessary for most research.

"It went up. It came down. But it had absolutely no scientific value," was Sagdeev's blunt assessment of the 31/2-hour, unmanned orbital flight a week ago Tuesday of the Soviet shuttle that ended the U.S. monopoly on reusable spacecraft.

In a wide-ranging interview with The Associated Press, the 55-year-old physicist confirmed he voluntarily left the top post at the agency that handles space exploration and astronomy because he felt no one person should dominate an institute for such a long time.

Sagdeev, a longtime member of the Soviet Academy of Sciences, said he would concentrate on his own research and the think tank he heads that advises Gorbachev on arms control.