NASA video clips of the incident, which have been viewed more than 100,000 times on YouTube, show Stefanyshyn-Piper reaching out, but to no avail. Now, Kevin Fetter, a veteran satellite observer in Brockville, Ontario, has spotted the lost tool bag using his backyard observatory and published a video of it online.

He captured the backpack-sized bag at the exact time it passed over his observatory. In an email interview, Fetter said his find had little to do with luck and he had planned to capture the tool bag on video as it was "something new in orbit". The US military tracks objects in space and releases orbital data about them, allowing star gazers to pinpoint their location. A satellite tracker tool on the SpaceWeather.com site allows people to determine exactly when objects such as the tool bag are going to be floating over their suburbs.

"Depending on the size of the object and how much light its surface reflects will determine if I can see it, and get it on video," Fetter said. Lister Staveley-Smith, professor of physics at the University of Western Australia and vice-president of the Astronomical Society of Australia, said military radars could track objects "much smaller than a tool bag" using equipment similar to the airport radars used to detect planes.

"The radio waves are sent out from a radar, they bounce off the tool bag or satellite and [then] they come back to Earth and are detected by a radar [receiver]," he said. The information allowed astronomers to pinpoint the location of the object to within a few metres from its actual location, he added. Fetter used a $900 Celestron Nexstar 102 SLT telescope fitted with a high-resolution camera, which was in turn connected via a networking cable to his computer. The set-up allows him to control the telescope from inside his house and record the video directly to his computer.

A detailed outline of Fetter's equipment and several video clips of his space observations can be found on his website. "I don't have any [professional] background in astronomy. Just one night I looked up at the night sky and got hooked on astronomy. It was many years later that I started satellite observing," he said.

Staveley-Smith said it was important for NASA to monitor the position of the tool bag as there was a remote chance it could cause damage to the space station. "As space junk goes it's quite small but because it's roughly in the same orbit as the space station itself there's a chance that it might later on collide with the space station's solar panels," he said. In an interview from the space station with The Associated Press after losing the bag, Stefanyshyn-Piper vowed to triple-check all tethers to avoid another incident.

"We're definitely not going to do it again. You're not going to see us lose another bag," she said.