U.S. Astronaut Scheduled to Make Russian Spaceflight : Mission: Blastoff for Mir 18 station is set for tonight. It marks closest such cooperation by two nations in 20 years.

In the pale sunlight of an icy desert dawn, a Russian Soyuz rocket was hoisted smoothly onto its launch pad Sunday, ready to blast the first American cosmonaut into space.

In a landmark of post-Cold War cooperation, U.S. astronaut Norman E. Thagard, who has spent a year in Russia preparing for the mission, is scheduled to lift off tonight with two Russian cosmonauts bound for the Mir space station.

The Mir 18 crew members will spend about three months on the space station conducting medical experiments. In June, the U.S. space shuttle Atlantis will rendezvous with Mir, deliver a fresh Russian-American crew and ferry Thagard and his colleagues back to Earth.

Two Russian cosmonauts have flown in U.S. space shuttles. But Thagard, a 51-year-old former Marine pilot, engineer and physician, will be the first American ever to fly in a Russian spacecraft.

Twenty years have passed since Russians and Americans worked together in space so closely. In 1975, the U.S. Apollo 18 and Russian Soyuz 19 linked up in space briefly, but hopes for more joint missions were dashed when detente ended.

“My comrades and I are happy that after 20 years we are resuming work together once again,” said Yaroslav V. Nechesa, head of the Baikonur Space Museum, who worked on the Apollo-Soyuz mission as a young officer.

“It should happen much more frequently-- dai Bog, “ Nechesa said, using the revived, post-Soviet expression for “if God wills it.” Many Russian officials see expanded international scientific and commercial cooperation as the only way to keep the Russian space program alive.

The Mir 18 mission was made possible by a broad 1992 agreement between former President George Bush and Russian President Boris N. Yeltsin on space cooperation.

In 1993, the two countries agreed to a two-year program of joint experimentation on Mir leading to the development of a new international space station. The United States signed a $400-million, four-year contract to buy Russian space equipment, expertise and up to 21 months on Mir for U.S. astronauts.

International openness is still a new concept at the Baikonur Cosmodrome, where secrecy was the byword from the outset. Moscow gave it the name it has even though the tiny town of Baikonur is almost 360 miles to the northeast.

Moscow knew that missile launches from what was then the southern Soviet Union would be detected, but it wanted to confuse Westerners as to their location, said Craig Covault, who has long monitored the Russian space program at Aviation Week magazine.

Thagard and his Russian colleagues will blast off from the same pad that launched Sputnik, the world’s first satellite, in 1957.

U.S. pilot Gary Powers was on a mission to photograph the launch pad when his U-2 spy plane was shot down in 1960. A year later, the same launch pad was used when Russian cosmonaut Yuri A. Gagarin became the first human in space.

But the failures of the Russian space program can also be seen along the narrow, bumpy road leading through the desolate base: the buildings with boarded-up windows, the abandoned launch pads for Russia’s aborted attempt to put a man on the moon.

The breakup of the Soviet Union stranded the cosmodrome in another country. Last year, the Russians signed a 20-year lease with Kazakhstan for the base, with an option to renew for 10 more years.

Last year, inflation and payment delays ate up the space agency’s budget. Last month, the space agency received “not a kopeck,” said its director, Yuri N. Koptev.

Although the financial situation remains critical, there are signs that the worst years for the Russian space program may be over.

In response to warnings that lack of funding could, among other things, jeopardize the 1993 agreement with the United States, the Russian government has promised it will double the budget that Parliament approved for the space program this year, to about $670 million. By comparison, the National Aeronautics and Space Administration’s annual budget is roughly $14 billion.