Tethers Unlimited, Inc.

Tethers Unlimited, Inc. (TUI) is an American private aerospace company headquartered near Seattle, Washington, which performs research and development of new products and technologies for space, sea, and air.

Founded in 1994 by Dr. Robert P. Hoyt and Dr. Robert L. Forward, Tethers Unlimited began developing products based on space tether technologies, including concepts for removal of space debris and momentum exchange tethers for launching payloads into higher orbits. TUI has since broadened its suite of technologies to include power, propulsion, actuation, and communications systems for small satellites, robotic technologies for on-orbit fabrication and assembly, optical fiber winding and deployment, software defined radio communications, and 3D printed radiation shielding.

In 2007, in collaboration with Stanford University, the company launched the Multi-Application Survivable Tether (MAST) experiment to test the survivability of tethers in space.