Three astronauts who had their stay on the International Space Station extended by a month after a rocket failure are set to land back on Earth on June 11, the head of Russia's space agency said Friday.

"Expedition 42/43 returns from the ISS to Earth on June 11," the head of Roscosmos space agency, Igor Komarov was cited by RIA Novosti state news agency as saying.

Komarov also said Russia would send a supply ship up to the ISS in early July, after one crashed back to Earth in early May after a rocket failure.

The next manned mission to the research outpost is then set to go ahead in late July.

The three crew members -- Russian cosmonaut Anton Shkaplerov, American astronaut Terry Virts and Italian Samantha Cristoforetti -- were originally due to leave the ISS on May 12.

Their departure was delayed when a Soyuz rocket carrying a Progress cargo ship with supplies for the ISS failed shortly after launch on April 28, causing it to fall back to Earth.

Roscosmos has said the problem was caused by a design fault in the rocket, not a defect in production.

Russia's space programme was hit by two failures within weeks in May, with the Progress crash followed by the failure of a Proton rocket carrying a Mexican satellite.

The same month, the former head of the company which manufactures the Soyuz rockets was charged with abuse of office over loans he granted to international partners and placed under house arrest.

To add to the space programme's litany of problems, British space tourist Sarah Brightman pulled out of a flight set for September for which she had paid $52 million, citing family reasons. No replacement has yet been named.