U. S. and Russian space agency officials, prompted by last week’s failure of an unmanned cargo mission to the international space station, are weighing options including temporarily pulling astronauts off the orbiting research facility.
A senior official from the U. S. National Aeronautics and Space Administration stressed on Monday that no final decisions have been made, and he said Russian experts were still “cautiously optimistic” they can determine and fix the cause of the recent rocket failure in a little more than two months.
That would be in time to avoid leaving the $100 billion orbiting laboratory operating entirely on automated systems.
But NASA is pursuing detailed contingency plans to have astronauts temporarily abandon the station if Russian Soyuz rockets aren’t cleared to resume flight before the last of the current residents are slated to leave, at the latest by mid-November. The replacement timetable is partly determined by the portions of the year when astronauts can land safely.
In a news conference, Mike Suffredini, manager of the station program for NASA, gave the strongest signals yet that within three weeks, the facility’s crew is likely to shrink to three astronauts from its normal six-person crew.
And unless Russia is able to successfully launch two unmanned Soyuz rockets by mid-November, Mr. Suffredini indicated, the remaining three crew members would head for home with no prospect of immediate replacement.
At that point, he indicated, the station’s international partners probably would have no choice except to temporarily keep it operating without any humans aboard.
“I want to emphasize to everyone,” he said, that the current crew is safe and “we have plenty of options” about how to keep the station performing safely with a three-person crew “or no crew.” The goal, Mr. Suffredini said, is “to protect that investment.”
comments came hours after Russian officials said the first three of the six astronauts currently orbiting the Earth are likely to return by mid-September, a week later than initially planned. But Interfax also quoted Alexei Krasnov, head of manned programs for the Russian space agency, saying the scheduled Sept. 22 launch of a replacement three-man crew has been delayed until late October or “the beginning of November.”
If the replacement crew fails to arrive by the middle of that month, however, managers effectively would have no choice but to temporarily leave the station without a full-time, live-aboard crew for the first time in more than a decade.
A Soyuz-U rocket carrying an unmanned Progress supply module malfunctioned shortly after launchlast week and the ship crashed in Siberia. The mishap raised questions about the safety of the Soyuz, the workhorse vehicle for the space station since the U. S. space shuttle flew its last mission in July. The third-stage rocket motor that failed last week is the same kind used on the Soyuz rockets that carry manned capsules to the space station.
A Russian government panel probing the accident is expected to release at least preliminary results by late next week, Interfax said.
Mr. Krasnov said Russian officials would like to conduct at least one and perhaps two unmanned launches of the Soyuz to confirm its reliability before sending up a manned mission.
Mr. Suffredini acknowledged the risks of leaving the space station unmanned. “There is a greater risk of losing” the station, due to some unexpected malfunction or onboard problem, he said, when there aren’t any astronauts able to troubleshoot.