The Russian Express-AM4 communication satellite, missing after Thursday's launch, could not separate from the booster and was found off the designated orbit, a source in the Russian space program said on Friday.
Experts told RIA Novosti the satellite is useless unless separation from the Briz-M booster rocket is performed.
"If separation from the booster fails, the spacecraft is done for, it won't be able to perform the designated tasks," an expert said on the condition of anonymity.
Another expert said the satellite was designed to operate at a geostationary orbit at a fixed station-keeping point which it was unable to reach.
"The booster creates a huge additional burden and the satellite's propulsion engine, which is not designed for maneuvering with additional weight, won't be able to take the satellite into the assigned geostationary orbit and station-keep it in the orbital position," the expert said.
The satellite's launch and orbital operation has been fully insured for 7.5 billion rubles ($259 million).
Russia's Proton-M rocket with the Express-AM4 satellite was launched from the Baikonur Space Center in Kazakhstan early on Thursday but mission control failed to establish communication with it.