Astronauts conducting a spacewalk on the International Space Station discovered a major problem on their most recent mission, a problem that is most definitely not insignificant: a piece of cloth shielding went floating away. The emergency prompted Astronaut Peggy Wilson to immediately report the problem to Mission Control, and NASA said they would monitor the piece to make sure it didn’t return and strike the station.

The shielding is very important because it protects the ISS from micrometeorite debris, and it is one of four pieces that Whitson and her colleague, Shanke Kimbrough, were installing on their latest spacewalk near a docking par. The three remaining shields were placed over the spots that were considered the most vulnerable.

It was an unfortunate mishap on what was a history spacewalk for Whitson, who became the world’s oldest and most experienced woman in space, as it was her eighth career spacewalk. She was clearly frustrated as she spoke to Mission Control, media reports indicated.

Here is a description of the spacewalks from NASA: “The first spacewalk will prepare the Pressurized Mating Adapter-3 (PMA-3) for installation of the second International Docking Adapter, which will accommodate commercial crew vehicle dockings. The PMA-3 provides the pressurized interface between the station modules and the docking adapter. Expedition 50 Commander Shane Kimbrough of NASA and Flight Engineer Thomas Pesquet of ESA (European Space Agency) will disconnect cables and electrical connections on PMA-3 to prepare for its robotic move Sunday, March 26. PMA-3 will be moved from the port side of the Tranquility module to the space-facing side of the Harmony module, where it will become home for the docking adapter, which will be delivered on a future flight of a SpaceX Dragon cargo spacecraft. The spacewalkers also will install on the starboard zero truss a new computer relay box equipped with advanced software for the adapter.”