Construction from the bottom up has benefits but users must proceed with caution
In 2014, International Space Station commander Barry ‘Butch’ Wilmore had a problem. He needed a torque wrench for a repair but it was missing from the toolkit – one of the joys of zero gravity. Normally, he’d have to wait for it to arrive on the next resupply rocket. This time, Nasa emailed Wilmore a file for the on-board 3D printer. Four hours later, Wilmore was holding the first object to be designed on Earth and sent digitally to space to be printed there.