When International Space Stationcommander Barry Wilmore needed a wrench, Nasa knew just what to do. They "emailed" him one. This is the first time an object has been designed on Earth and then transmitted to space for manufacture.

Made In Space, the California company that designed the 3D printer aboard the ISS, overheard Wilmore mentioning the need for a ratcheting socket wrench and decided to create one. Previously, if an astronaut needed a specific tool it would have to be flown up on the next mission to the ISS, which could take months.

This isn't the first 3D printed object made in space, but it is the first created to meet the needs of an astronaut. In November astronauts aboard the ISS printed a replacement part for the recently installed 3D printer. A total of 21 objects have now been printed in space, all of which will be brought back to Earth for testing.

"We will use them to characterise the effects of long-term microgravity on our 3D-printing process, so that we can model and predict the performance of objects that we manufacture in space in the future," explained Mike Chen from Made in Space.

Chen also explained the process of sending hardware to space. First, the part is designed by Made In Space in CAD software and converted into a file-format for the 3D printer. This file is then sent to Nasa before being transmitted to the ISS. In space the 3D printer receives the code and starts manufacturing.

"On the ISS this type of technology translates to lower costs for experiments, faster design iteration, and a safer, better experience for the crew members, who can use it to replace broken parts or create new tools on demand," Chen said.