Damaged Puerto Rico's Arecibo telescope collapses

The Arecibo Observatory telescope in Puerto Rico has collapsed. This happened when the telecope's 900-ton receiver platform fell 450 feet (140 metres) and smashed onto the radio dish below.

Engineers had recently warned of the huge structure's decrepit condition, and the US National Science Foundation (NSF) announced only last month that it would be dismantled.

Abel Mendez, director of the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, said the platform fell before 8:00am (1200 GMT). He described it as "a total disaster."

Two cables that held the platform in place over the radio dish -- which measures 1,000 feet (300 meters) in diameter -- had snapped this year, and the structure finally gave way on Tuesday morning.

Photographs showed clouds of dust rising into the air.

The telescope was one of the largest in the world and has been a tool for many astronomical discoveries since the 1960s, as well as being famous for its dramatic scale and setting.

The telescope once starred in a James Bond film. An action scene from the Bond film "GoldenEye" took place high above the dish, and in the film "Contact" an astronomer played by Jodie Foster used the observatory in her quest for alien signals.

The telescope was in operation until August this year, and scientists had lobbied the NSF to reverse its decision to close the site.

In August, an auxiliary cable failed after slipping from its socket in one of the towers and left a 100-foot gash in the dish below.

Engineers were working to determine how to assess and repair the damage when a main cable connected to the same tower broke on November 6.

Before Tuesday, a controlled demolition had been planned to avoid an unexpected collapse.

Among the telescope's successes was in 1992 discovering the first exoplanet -- a planet outside the Solar System -- and in 1981 it helped produce the first radar maps of the surface of Venus.