A rocket exploded on its launch pad Friday during tests just days before liftoff, killing 21 people and injuring 20 others, the Brazilian defense ministry said.

The blast in northeastern Brazil killed mostly civilian technicians, destroyed two research satellites and delivered a serious blow to Brazil's nascent space program. Brazil is trying to be the first Latin American nation to put a satellite in orbit.

"We have recovered more bodies and now know of 21 dead. We don't expect number of dead will increase further," said Brazilian air force spokesman Lt. Ricardo Olanda, adding the investigation into what caused the accident was expected to take 90 days.

The explosion occurred after one of the four main motors of the VLS-3 rocket accidentally ignited for reasons still unknown, Defense Minster Jose Veigas Filho said.

An explosion followed that decimated the launch pad, a box-like structure that surrounded the 100-foot high white rocket on three sides.

"The launching pad collapsed and the technicians were working there," Veigas said. There was no damage outside the launch area, officials said.

Globo television showed footage of a plume of smoke rising into the sky over the seaside Alcantara Launch Center near Sao Luis, about 900 miles north of Brasilia.

Most of the injured were taken to a hospital in neighboring Sao Luis de Maranhao, about 20 minutes by flight from the launching base.

"We had just done two days of tests and everything went well — 100 percent. Everybody is devastated," said air force Col. Romeo Brasileiro.

The US$2.2 million rocket, scheduled to launch on Monday, became Brazil's third failed attempt to send a rocket into space with a research satellite.

Presidential spokesman Andre Singer said Brazil was committed to continuing with its space program.

"The government wants to reaffirm its willingness to continue its effort to provide Brazil with a space technology of its own," Singer said. "Brazil's space program is an important scientific and technological project of our country, today is a day of mourning."

Veigas met with President Luiz Inacio Lula da Silva Friday night to provide details of the accident.

A rocket launched in November 1997 crashed in the Atlantic Ocean after suffering engine problems shortly after blast off.

In December 1999, another Brazilian rocket developed problems and failed three minutes after takeoff. Officials remotely destroyed the rocket.

The Alcantra base is considered a near-ideal launch because of its location, just 2.3 degrees south of the equator. The Earth's rotation is faster at the equator, which helps propel rockets into space with up to 13 percent less fuel, which allows heavier payloads.

Brazil is currently negotiating with the United States and the Ukraine to allow use of the base to launch their rockets.

(China Daily August 23, 2003)