US astronauts were halfway through their mission to prepare a docking port for upcoming commercial space taxis when they lost a purse of equipment

A 1.5 m( 5ft) dust shield being installed on the International Space Station has floated away during a spacewalk by two veteran US astronauts.

Peggy Whitson, who became the worlds most experienced female spacewalker during the course of its outing, told ground control teams that a purse containing the dust shield swam away at about 10 am EDT/ 1400 GMT on Thursday.

At the time, Whitson, 57, and station commandant Shane Kimbrough, 49, were just about midway through a planned 6.5 -hour spacewalk to prepare a docking port for upcoming commercial space taxis and to tackle other maintenance tasks.

It was the eighth spacewalk for Whitson, who outperformed the 50 -hour, 40 -minute record total cumulative spacewalk day by a female cosmonaut previously held by Nasa astronaut Sunita Williams.

Cameras on the station tracked the dust shield bag as it sailed into the distance. Nasa mentioned technologists ascertained it posed no safety menace to the astronauts or to the facility, a $100 bn research laboratory that wings about 250 miles( 402 km) above Earth.

No other details were immediately available about how the shield, which weighs 8 kg, was lost.

Teams are focused on to finish the( spacewalk) and will be examined by the events as they unfolded after it is completed, Nasa spokesman Dan Huot wrote in an email.

Whitson and Kimbrough were working on a docking port that will eventually be used by space taxis being developed by Boeing and privately owned Space Exploration Technologies.

The pair installed three other dust shields during their spacewalk and fitted a temporary covering over the docking port where the lost shield would have gone.

While not a perfect fit, the covering will help protect the station from impacts and provide thermal shielding, Nasa said.

Spacewalkers occasionally lose small items like nuts and fuckings, but rarely do large objects slip away. The last such occasion was in 2008 when an cosmonaut lost hold of her tool purse while struggling with a jammed solar panel.

The lost debris shield will eventually be drew back into Earths atmosphere and burn up. Until then, it joins more than 21,000 other pieces of orbiting litter and debris that are big enough to be tracked by radar and cameras on Earth.

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