ROME, Feb 1: An incorrect angle of re-entry through the earth’s atmosphere could have caused the US Space Shuttle Columbia to disintegrate, Italian astronaut Umberto Guidoni said Saturday.

“It is too early to speculate on the precise causes of the accident but the images from Texas suggest that the Columbia broke up into at least three pieces due to an improper angle as it returned into the atmosphere,” Guidoni, who has participated in two space flights, told Italy’s ANSA news agency.

“Re-entry through the atmosphere is one of the most critical moments in the mission of the shuttle. An error of several degrees (on re-entry) could provoke a catastrophe similar to what happened today,” Guidoni said.

“The angle of penetration should be at 40 degrees to the horizon... The margin of error is at most three or four degrees. Beyond that range the shuttle becomes uncontrollable,” said the astronaut.

Another experts said the failure of the heat resistance system could have caused the disintegration.

German space expert Heinz-Hermann Koelle said: “That’s what the pictures seem to show,” Koelle told Germany’s n-tv, referring to television footage showing several white trails emanating from the shuttle as it re-entered the atmosphere Saturday 100 miles (160 kilometers) south of Dallas, Texas.

Re-entry is one of the most dangerous moments in space missions, as the sudden slowdown of spacecraft as they re-enter the earth’s atmosphere from speeds of 28,000 to 1,100 kilometres per hour causes extreme heat, said Koelle, who spent more than a decade working in the United States.

United States space shuttles are covered in heat-protective tiles.

The shuttle’s seven passengers would have died within “10 seconds” of the incident, he said.—AFP