Russia's top space official said Thursday that US plans for manned missions to Mars were unrealistic and said the emphasis for space exploration should be completion of the International Space Station (ISS).

Yuri Koptev, head of Russian space agency Rosaviakosmos, distanced himself from President Vladimir Putin's comments this week that Russia could work with the United States on US President Bush's ambitious plans.

He was particularly critical of Bush's plan for designing a spacecraft capable of carrying astronauts to the space station, the moon and Mars, saying he did not understand how this could be done since each destination had different needs.

"Yes, we can agree that certain elements could be used. However, there cannot be a universal spacecraft as is being suggested at the moment," he said. "I don't think we will work together on this project."

He dismissed Bush's ideas as an eye-catching ploy linked to his campaign for re-election.

He said the 16-nation ISS was Russia's priority and called for construction there to be completed within the original time frame of the next two years, despite building being delayed for almost a year since the United States grounded its shuttle fleet.

The shuttle has faced delays before, including the Russians being two years late delivering a key component, the Zvezda service module. US contractors also have run more than US$1 billion over budget.

"We are insisting on the execution of the decision taken at the end of 2002 in Tokyo, which says the construction of the station should be finished within 1.5-2 years," Koptev told reporters, referring to a meeting between the leaders of space agencies involved in the ISS.

He also said he wanted to boost the number of astronauts on the station to six as soon as possible, but did not explain how this would be done. A two-man crew is currently on the orbital platform.

Delays

The building of the space station has been delayed since last February when the United States grounded the shuttles after Columbia exploded on re-entry, killing all seven astronauts on board.

US space officials have said the shuttles, the only crafts capable of delivering large sections of the station to the ISS for assembly, should return to service in September.

Russia, temporarily the sole supplier of manned and cargo ships to the station, launched a Progress cargo ship Thursday, delivering food, fuel, water and scientific equipment to the outpost.

Koptev said the European Space Agency could play a key part in the station, when its new cargo ship -- the Automated Transfer Vehicle (ATV) -- makes its scheduled debut journey to the ISS by September.

When Bush outlined his space plans earlier this month, he said shuttles would be retired in 2010 once the space station was complete.

Koptev said Bush's plans to send humans back to the moon and then on to Mars were simply connected to his election campaign as had been the case with previous US presidents.

"We understand that to a large extent our US colleagues came up with these plans as part of a pre-election campaign," he said, adding funding was the primary barrier.

(China Daily January 30, 2004)