It is expected that the Russian space agency will announce the failure of the Phobos-Grunt mission in the next few days.
Launched on Tuesday, the ambitious Mars moon mission remains stranded in Earth orbit.
The probe's engines failed to fire, preventing the mission from coasting to Mars.
A solution has yet to be found and sources are indicating that efforts to save the mission have failed.
Efforts to resume contact with a Russian space mission to Mars stuck in Earth orbit after launch have failed and the probe must be considered lost, Interfax news agency reported Saturday.
"All attempts to obtain telemetric information from the Phobos-Grunt probe and activate its command system have failed. The probe must be considered lost," Interfax quoted a source in the Russian space sector as saying.
The source said Russia's space agency would announce the failure of the mission in the next few days.announce
The space agency had said earlier scientists had a window of only a few days to reprogram the probe in a bid to send it on its route to Mars. If this does not happen, Phobos-Grunt would fall back to Earth early next month.
The mission went awry after launch Wednesday when the five-billion-ruble ($165 million) probe's engine failed to fire, leaving it orbiting the Earth rather than starting its journey towards the red planet.
The probe had the unprecedented mission to land on the Martian moon Phobos and bring a sample of its rock back to Earth, as well as launch a Chinese Mars satellite.
The mishap caps an inglorious list for Russia's space program in the 50th anniversary year of Yuri Gagarin's first flight into space.
Three navigation satellites plunged into the sea after a failed launch in December and Russia has since lost new military and telecommunications satellites upon launch.
The accident also comes just days before Russia is due to resume manned space flights to the International Space Station that ground to a halt in August with the crash of a cargo craft.