The U.S.- Russia satellite collision will help raise world awareness of the threat of orbital debris, a U.S. space expert said Thursday, calling for international cooperation to remove the debris.

The debris clouds from Tuesday's collision will pose some risk to the upcoming launch of the U.S. space shuttle Discovery and to the International Space Station (ISS), said Mark Matney, a scientist at the Orbital Debris Program Office in NASA's Johnson Space Center.

But he added that at this point, their models seemed to indicate that the difference in altitude would minimize the risk.

"If the ISS orbited at an altitude up closer to the collision altitude of 790 km, then it would be a different story," Matney told Xinhua Thursday in an email interview.

A privately-owned U.S. communications satellite collided Tuesday with a defunct Russian military satellite in space, shooting out massive debris clouds.

Matney said it is very difficult to predict collision conjunctions accurately, since satellites travel at very high velocities.

Actually, a collision in space between any satellites was rather high, given enough time and enough satellites, he said.

"It is like the lottery -- the probability of any one person winning is quite small, but the probability that someone is a winner is quite high," Matney said.

While most satellites operate their full lifetime without experiencing any serious damage from debris, the problem continues to grow and will become more important in future years, Matney said. "We will continue to monitor the situation."

According to Matney, historically, the United States and Russia have launched the most of objects into space and their space activities have created a large amount of debris through the years.

The two countries are implementing many policies to limit the production of orbital debris, along with the other space-faring nations. Tuesday's accident will help spread awareness of this important topic, he said.

The space expert called the debris limitation "an international problem" which "requires all users of space to work together to make space safe for future generations."

He hoped that the international community would work hard to minimize the production of debris. "This is an international problem, and requires international cooperation to solve."

On efforts to remove the debris, Matney said the natural atmospheric drag could remove some, but it is generally too slow.

For future missions, scientists can deliberately design satellites to de-orbit more quickly, he said. For satellites already there, he added, "we would need some sort of 'space tug' to remove them."

The best way to avoid such kind of collision is to design spacecraft so that they are removed from the environment at the end of life, which will help avert the growth of satellite mass in Earth orbit, Matney said.

Source:Xinhua