The European Space Agency (ESA) is showing 3D-printed metal parts made onboard the International Space Station using a printer and materials the agency sent earlier this year.  While 3D printing onboard the ISS is nothing new, the printing of metal parts in space is an important advancement. The agency’s goals are to be able to produce more tools and spares in situ rather than having to rely on resupply missions. An ambitious idea being pitched is to use captured space debris as input as well, which would further decrease the ISS’s dependence on Earth and expensive cargo runs from the bottom of the gravity well.

The 180 kg 3D printer lives in the European Drawer Rack Mark II inside ESA’s Columbus module. Controllers on Earth managed the printing process after installation. The printer ran for about four hours a day, with each layer inspected before continuing. This means the printing process took days, but running the machine continuously would, of course, cut printing time significantly.

The printer uses stainless steel wire that is fed to the printing location, where a laser melts it. As the pool of molten metal moves away from the laser-heated spot, it solidifies like plastic does in a regular FDM printer. Of course, with the melting point of stainless steel being around 1400 °C, it runs a lot hotter and thus requires that the printer to be inside a completely sealed box, with the atmosphere inside vented into space and replaced with nitrogen prior to starting the printing process. The presence of oxygen would totally ruin the print.

We badly want a practical metal printer for home use, but, so far, they remain out of reach. When you do get them, you might consider that there are different design rules for metal-printed parts.

Recently Canada’s Canadarm2 caught its 50th spacecraft in the form of a Northrop Grumman Cygnus cargo vessel since 2009. Although perhaps not the most prominent part of the International Space Station (ISS), the Canadarm2 performs a range of very essential functions on the outside of the ISS, such as moving equipment around and supporting astronauts during EVAs.

Officially called the Space Station Remote Manipulator System (SSRMS), it is part of the three-part Mobile Servicing System (MSS) that allows for the Canadarm2 and the Dextre unit to scoot around the non-Russian part of the ISS, attach to Power Data Grapple Fixtures (PDGFs) on the ISS and manipulate anything that has a compatible Grapple Fixture on it.

Originally the MSS was not designed to catch spacecraft when it was installed in 2001 by Space Shuttle Endeavour during STS-100, but with the US moving away from the Space Shuttle to a range of unmanned supply craft which aren’t all capable of autonomous docking, this became a necessity, with the Japanese HTV (with grapple fixture) becoming the first craft to be caught this way in 2009. Since the Canadarm2 was originally designed to manipulate ISS modules this wasn’t such a major shift, and the MSS is soon planned to also started building new space stations when the first Axiom Orbital Segment is launched by 2026. This would become the Axiom Station.

With the Axiom Station planned to have its own Canadarm-like system, this will likely mean that Canadarm2 and the rest of the MSS will be decommissioned with the rest of the ISS by 2031.

Top image: Canadarm2 captures Cygnus OA-5 S.S. Alan Poindexter in late 2016 (Credit: NASA)