Two spacewalkers stepped outside the International Space Station (ISS) on Thursday in order to perform vital maintenance on the Space Station Remote Manipulator System (SSRMS), via replacing one of its Latching End Effectors (LEE). The spacewalk got underway at 12:05 GMT and successfully replaced the LEE with time to spare.
The LEE allows the SSRMS to grapple onto objects, and the SSRMS has one LEE on each of its ends, in order to enable the SSRMS to relocate itself around the ISS via so-called base changes.
The LEE features three snares which close around a grapple pin on target objects, in the same way that the Space Shuttle’s robotic arm used to work. This enables the LEE to grapple any object which features a Flight Releasable Grapple Fixture (FRGF) interface.
However, the LEE also has some more complex features due to the fact that it was designed for long-terms use on the ISS. Specifically, it features latches, which allow it to securely clamp itself onto compatible Power & Data Grapple Fixture (PDGF) interfaces, and also electrical and data interfaces which can connect the arm to the object it has grappled.
This latching capability allows the arm to tightly ...