The Russian Space Agency on Tuesday announced that it is postponing the launch of the latest space station crew to Nov.12. This gives NASA reasons to worry, since the situation is such that NASA itself has no space shuttles to take the astronauts to the International Space Station, and it relies completely on Russia for the same.

For NASA, the flight in July was the last one and it meant that NASA would move on to more ambitious destinations, whereas the job of ferrying people and supplies to the orbiting research station would be taken up by other companies.

But then, recent rocket malfunctions, including the one on Aug. 24 by a Russian ship that was taking tons of supplies to the space station, has caused worry. The rocket that failed in August is similar to the one that will be used in November by the Russians to carry astronauts. An American astronaut will also be on board.

The reason for the failure of the engine was later found to be a manufacturing defect on a fuel pipe that caused the third-stage engine to shut down. The finding obviously raised concerns pertaining to the quality control in the Russian rocket factories.

You can't put your head in the sand about the fact that you're going to have failures, Christopher C. Kraft, the former director of NASA's Manned Spaceflight Center told Failures are to be expected in vehicles as old as the Soyuz -- or the American shuttle for that matter, Kraft added.

It would be better if the space station were not reliant on any one nation, New York Times quoted Scott Pace, director of the space policy institute at George Washington University as saying.

There are American Companies with which NASA has contracts to carry cargo to the space station and which hope to establish contracts to be space taxis for humans. But then the whole idea does not look like its happening in reality as The Orbital Sciences Corporation of Vienna, Va., one of the two companies which are supposed to be carrying cargo to the space station next year, suffered an engine setback in June during a ground test.

Also, Space Exploration Technologies Corporation of Hawthorne, Calif. or SpaceX, the other company to have a contract, does not appear promising enough after it could not explain until last week, the overheating of engines during an otherwise highly successful test flight last December. SpaceX aims to take its first load of cargo to the space station in December, the report said.

NASA has assured that the crew staying in the International Space Station has enough food and supplies including water and oxygen for their survival.

Three of the six crew members in the space station will return this week on one of the two Soyuz capsules docked up there, while the other three must leave in the remaining capsule by Nov. 19.

Once the space station is empty, the station can be operated from the ground. But it could turn disastrous if a malfunction gets the $100 billion space station tumbling out of control. That could mean putting at risk the entire human spaceflight program of the United States, Russia and other participating nations.

Russian space officials have said that they would launch two unmanned Soyuz rockets - one to launch satellites and the other to carry cargo to the space station - before sending up people again.