The six-member crew of the International Space Station took shelter in two Russian Soyuz spacecraft early Tuesday because of a predicted close approach by an unknown piece of space debris. Radar tracking indicated the debris could pass within about 820 feet of the space station at 8:08 a.m. EDT (GMT-4), but no impact was detected and the crew was told to resume normal operations.

“We are currently at TCA plus four minutes and you are clear to egress Soyuz,” Kjell Lindgren radioed the crew from mission control in Houston at 8:12 a.m., four minutes after the time of closest approach.

“Copy that. Thank you,” replied Expedition 28 flight engineer Satoshi Furukawa.

Safety procedures are put into effect when radar tracking indicates debris could pass within an imaginary box around the space station that takes into account tracking errors to provide a margin of safety. “Sheltering in place” aboard the Soyuz crew ferry craft is required when notification of a possible debris “conjunction” occurs too late to orchestrate a space station maneuver to get out of the way.

The size and source of the debris were not immediately known.

Space debris is an ongoing concern for space station crews because of the extreme velocities of objects in low-Earth orbit — about five miles per second.

(Source: SFN)