Russia on Tuesday blamed a computer malfunction caused by the impact of cosmic rays for the failure of its Phobos-Grunt mission to Mars, one of a litany of setbacks for its embattled space programme.

Announcing the initial results of the investigation into the Mars mission, Russian space agency Roscosmos also revealed the next manned launch to the International Space Station would be delayed due to technical problems.

The Phobos-Grunt probe -- which was to have brought home a sample of soil from Mars' largest moon -- crashed back to Earth earlier this month after becoming stuck in Earth's orbit shortly after its launch in November.

"The most likely reason in the commission's opinion is the local influence of heavy charged particles from outer space on the onboard computer system," Roscosmos chief Vladimir Popovkin said, quoted by RIA Novosti news agency.

The unmanned probe was launched November 9 in an ambitious mission to fly to Mars's largest moon, Phobos, in a first step towards Russia's dream of taking a manned mission to Mars.

But it failed to leave a low orbit around Earth, before gradually descending and crashing on January 15 over the Pacific Ocean.

Cosmic rays apparently led the onboard computer system to experience memory problems after launch which led to parts of the system restarting and going into energy-saving mode, the Roscosmos chief said.

Staff at the rocket-building plant had been punished for non-criminal offences, he said.

"Carrying out such a large-scale, lengthy job, they should have taken into consideration the effect of outer space on the equipment of an interplanetary station."

He also blamed sub-standard or fake foreign-made microchips used in the probe, saying more than 60 percent were not designed for use in space.

"This is imported equipment and of course this is probably a reason," he said.

Russia had previously speculated that radiation from US radar could have put the probe out of action.

But a space industry source told RIA Novosti it was "absolutely ridiculous" to claim the developers did not account for the effects of the cosmic radiation that is constantly bombarding the Earth's atmosphere.

"They weren't making a vacuum cleaner but a spaceship that had to fly in the aggressive environment of outer space and it is just impossible that they did not consider this," the source said.

The long-running project had undergone numerous modifications that were untested in space, Lev Zeleny of the Institute of Space Studies told the Interfax news agency.

"Practically it was newly constructed. ... I think that was one of the main reasons for the failure."

"There was a series of the most blatant errors in designing the craft that led to it being impossible to use," Igor Lisov of Space News magazine told Kommersant FM radio station.

Popovkin also confirmed that the next manned flight to the International Space Station, scheduled for March 30, would be delayed by a month because of flaws that showed up in testing of the Soyuz space capsule.

"The reason is the criticisms that came up while testing the ship," he said, Popovkin said, with the official date to be set Thursday after a teleconference with NASA.

Earlier Tuesday the head of manned programmes at Roscosmos, Alexei Krasnov, said the re-entry capsule of the Soyuz TMA-04M space ship was found not to be hermetically sealed.

The mission will ditch its faulty re-entry capsule and launch with one intended for the following mission scheduled May 30, which in turn will be delayed.

Russia has experienced an embarrassing string of failures over the last year, including the crash of an unmanned spaceship taking supplies to the ISS.

On Tuesday, Popovkin said Russia's space programme up to 2030 would cost between 150 and 200 billion rubles ($4.9 billion and $6.6 billion) a year.