Tethers Unlimited: Robotic Manipulation for In-Space Robotic Arms

Tethers Unlimited collaborates with PickNik to build advanced robotic control software


Tethers Unlimited, Inc. (TUI) – A subsidiary of AMERGINT Technology Holdings – is a pioneer of innovative space technologies, including software defined radios for satellite communications and mesh networks, advanced propulsion solutions for orbital maneuvering and orbital debris mitigation, and robotic systems for in-space manufacturing, servicing, assembly, and exploration.

TUI had developed their KRAKEN Robotic Arm for in-space servicing and assembly operations, and they had a new contract with NASA to put the KRAKEN arm to use tending payloads inside the International Space Station (ISS). To control the arm TUI chose to leverage the popular Robot Operating System (ROS) and the MoveIt motion planning software. They had an early prototype of a ROS application that had been used to successfully demonstrate a pilot system.


An internally developed legacy simulation was being adapted for the new project, and reliability issues were hindering progress. They needed quick access to expertise with ROS systems and MoveIt best practices to reconstruct their application for scalability and reliability with modern ROS systems.


TUI reached out to the team at PickNik Robotics for support in refactoring their robotics software to hit upcoming deadlines. PickNik engineers were able to remotely collaborate with the TUI team to revive the application functionality, and implement best practices and documentation. PickNik drew on their vast experience with ROS, MoveIt, and Gazebo to take TUI’s ROS packages to the next technical readiness level.

In addition, an effort was undertaken to improve the KRAKEN CAD model for use with ROS’ URDF modeling standard. PikNik advised TUI on how to improve the model assembly and structure for clean export to URDF, and improvements were made to better support physics simulation in Gazebo.


PickNik’s collaboration with Tethers Unlimited has provided the foundation for TUI to resume development of their robotic space applications. The open source MoveIt software framework, provided by PickNik, quickly allowed TUI to achieve advanced manipulation capabilities. This enabling robotic arm technology aids in TUI’s greater goal of extending humanity’s reach into the solar system through in-space manufacturing, servicing, assembly, and exploration missions.