Luna Innovations Incorporated is proposing to design, build, and test a shape, length, and tension sensing tether for robotic exploration and sample-gathering missions on remote planets and moons. The proposed tether system is capable of determining the location and orientation of marsupial robots as they navigate difficult terrain. The tether system will also provide shape and tension information along the entire tether, distinguishing elevation changes, tension due to snags, and potential points of harm. The tension feedback is particularly crucial, as it can be used to determine whether the rover has fallen down a slope or cliff, lost traction, or whether it is still moving under its own power. The system is based on Luna's unique fiber optic position and shape sensing technology, and is an enabling technology for obtaining images, data, and samples in areas with difficult terrain. In addition to providing new, vital feedback, the fiber optic shape sensor within the tether is lightweight, small, and flexible. Luna's unique shape sensing fiber also has the potential to provide both communication and power through the same fiber, further reducing the size and weight of the total tether package.