Security officials of the Brazilian state of Maranhao, where the space center -- the world's closest to the equator -- is located, put the toll at 19 dead and 20 injured.

The prototype rocket was being prepped to launch two Brasilian observation satellites into orbit next Monday when it exploded, virtually carbonizing the bodies of the victims and destroying the satellites, officials said.

"Because it was impossible to identify the bodies, we were forced to hold a roll call of technicians" in order to ascertain by a process of elimination who was missing, said Viegas.

The explosion was triggered when one of the rocket's four main thrust engines was unintentionally fired up. The platform on which the technicians were working disintegrated.

Viegas, who was to travel to the space center on Saturday, said an investigation would be launched to determine the cause "with speed and efficacity."

"On behalf of the government I want to express deep regret over the death of these workers who were laboring in such a noble cause," Viegas said.

Brazilian President Luiz Inacio Lula da Silva "deplored" the accident and "paid homage to the victims and their families," his spokesman said, adding that he had "reaffirmed" Brasil's determination to pursue space technology.

Television images shot by an amateur cameraman from a nearby beach showed the rocket and pieces of the launcher disintegrating in the air. A blaze on the launch pad that followed the explosion had been brought under control, reports added.

About 700 people worked at the base, which is in the jungle on a peninsula jutting into the Atlantic Ocean. About 220 people were working on the launch project, of which only a small team was on the launch platform at the time of the accident.

The aeronautics command was scheduled to launch the vehicle on August 25.

Globo Television, citing an Air Force officer, said that most of the victims were civilian technicians working at the space center.

The VLS rocket was the third prototype in a series, a spokesman with the Brazilian Space Agency said. He said the 50-tonne, 19 meter (62 feet) vehicle can carry up to 40 tonnes of fuel and had cost about 6.5 million dollars.

The vehicle is one of the most simple of its type, with an orbital range of 1,000 kilometers (600 miles). It was to have given Brasil a long-sought entree into the world satellite launch market and was the project's third failure.

Rocket launches were aborted for technical reasons shortly after takeoff in 1997 and 1999.

SPACE.WIRE