Lyappa arm
The Lyappa (or Ljappa) arm, officially Automatic system of re-docking (), was a robotic arm used during the assembly of the Soviet/Russian space station "Mir". Each of the "Kvant-2", "Kristall", "Spektr" and "Priroda" modules was equipped with one of these arms, which, after the module had docked to the Mir Core Module's forward (or axial) port, grappled one of two fixtures positioned on the core module's hub module. The module's main docking probe was then retracted, and the arm raised the module so that it could be pivoted 90 degrees for docking to one  of the four radial docking ports. Both the Wentian and Mengtian modules of the planned Tiangong space station will carry Lyappa arms to enable them to manoeuvre around the docking hub of the "Tianhe core module". Likewise the Prichal module will host the grapple fixtures for the redocking of future modules docked to it from one port to another using the Lyappa Arm attached to those modules. Name. The word “Lyappa” does not exist in Russian. It is probably a corruption of .