Russia's space agency Roskosmos is considering ending a permanent human presence in space, an agency official said on Wednesday following last week's crash of a supply ship delivering precious cargo to the ISS.
"Perhaps in the future, we will not need a constant manned presence in the lower Earth orbit," Roskosmos deputy director Vitaly Davydov told journalists in Moscow.
"We don't exclude the possibility of returning to the concept of DOS (long-term orbital) stations that we had before stations with constant human presence," he said.
Soviet-era space station designs, which included the early Salyut station series, were not meant to constantly house cosmonauts but instead served as a base for incoming missions.
Davydov's remarks came days after a failed launch left the International Space Station without a planned delivery of 2.9 tonnes of food, water, and fuel and delayed the next manned launch by at least a month.
Russia's space officials have for the first time warned that the current crew aboard the ISS could be evacuated, leaving the station, whose cost has been estimated at $100 billion, unmanned.
Such prospects have alarmed NASA as "there is a bigger risk of losing the ISS if there are no astronauts on board," according to the agency's ISS program chief Mike Suffredini.
Davydov denied that an unmanned ISS faces any threat. He confirmed however that the next planned landing of three cosmonauts currently at the ISS will happen a week later than planned, on September 16.
He did not provide any details on the delay of the next launch, which was originally scheduled for September 22, referring to an ongoing investigation into the causes of the launch failure.
Roskosmos chief Vladimir Popovkin said in a recent interview that he regretted Russia having put so much emphasis on manned space flight, rather than looking into more financially rewarding spheres like telecommunications.