The Russian space agency, Roscosmos, which has given up hope of recovering the spacecraft, is now concentrating on figuring out what will happen to the pieces that fall to Earth.

The agency expects about 20 to 30 fragments totaling about 440 pounds (200 kilograms) to reach the ground, with very low risk to people.

"Due to its predominantly low-melting construction materials, Phobos-Grunt will largely burn up during its reentry, so the corresponding risk to the population on ground is low," said Heiner Klinkrad, head of the space-debris office at the European Space Agency's space operations center in Darmstadt, Germany.

Phobos-Grunt is also carrying 11 tons of toxic fuel propellants, all of which should be consumed by the massive fireball at reentry.

"Roscosmos does not expect any environmental contamination—neither for an impact