can be combined into a manipulator, depending on the requirements for a particular application. The  primary parts of a manipulator are labeled on the left of the figure and the components of a joint are labeled on the right. When developing a manipulator with the architecture depicted in Figure 1, tension elements can be used to actuate and stiffen a joint as well as stiffen a link. The motors used to actuate  the joint can either drive hoists, where excess tension material (for example cable) is spooled, or drive capstans where the tension elements circulate from one side to the other. These tension networks increase the stiffness of the manipulator dramatically, allowing compression members with smaller cross  sections to be used and lighter overall systems to be realized compared to the current state-of-the-art manipulators such as the SSRMS and SRMS. The spreaders (identified in the figure) are used to provide  joint stiffening and mechanical advantage about the joint. Single spreaders above and below the joint, or multiple spreaders (depending on design requirements) can be incorporated as shown. Similar to joint  spreaders that aid articulation, link towers (which are fixed elements along the link) can be used to  provide a tension path to increase link stiffness. The components of a single joint are identified on the right side of Figure 1. The joint rotates about the  joint axis, identified in red in the middle of the figure. In this example, the capstan (B) and pulleys (A,C,D) are located equidistant from the joint axis and a single capstan (with dual warping profiles) located along  one of the links is used to actuate the joint. The number and location of the drive motor(s) that actuate the joint can be varied, allowing significant design freedom to meet mission requirements. The link-mounted  capstan in the figure has two warping end profiles of different diameters that operate two circulating cable  loops simultaneously to achieve joint articulation. Extension/contraction of the springs shown in the figure are used to accommodate changes in the total cable path as the joint articulates. Many variations of the joint architecture shown in Figure 1 are possible, with four possibilities shown in  Figure 2. Starting in the upper left with image “I” and using the nomenclature defined on Figure 1, first the  distance from “A” and “B” to the joint axis does not need to be equal as shown in Figure 2. In image “I” of  Figure 2, “B” has moved to the end of the link. This arrangement uses a single cable, one each above  and below the link, to not only stiffen the link, but also to stiffen and actuate the joint. The location of “B” in Figure 2 can be selected to be at any point along the link. The image also shows a manipulator configuration where the tension element is no longer in contact with the spreader, referred to as “spreader liftoff”. Allowing liftoff is optional because it results in the tension element sweeping through a large portion of the workspace which might cause interference. However, a benefit of liftoff is that it enables significantly increased force to be applied between the link ends, achieving a large amount of joint torque. In Figure 2, image “II” in the upper right, the dual capstan warping end profiles may be the same diameter  and combined with a single motor located along one of the spreaders. This results in one of the simplest  configurations from a control standpoint. In the lower right of Figure 2, image “III” shows multiple  spreaders used above the links. Additional spreaders can be located above or below the links and any  number of spreaders can be used. In the final image in the lower left of Figure 2, four motors are used to  actuate the joint, each one driving separate tension elements that run between the link end point and the top of the spreader. For optimal performance, each motor must be synchronized to keep the spreader tips equidistance form the links. Using multiple motors allows for many advanced control schemes including dynamic damping of structural modes. Image “IV” also depicts constrained lift-off, where the tension  element along the lower portion of the joint is encapsulated and forced to remain affixed to the spreader,in this case, by a telescoping member that allows for some increase in spreader height. In Figures 1 and  2 the joint rotation axes between successive joints have been shown as parallel and tension stiffening is  only shown in the plane of articulation. Successive joint rotation axes can also be rotated relative to one  another and tension stiffening can be applied in multiple directions. Tension stiffening enables much smaller tr uss cross sections to be used while achieving equivalent in tip  deflection performance. For example, the 4-link manipulator shown in Figure 3, where the actuation tendons are connected to the link ends, places the links in pure compression, avoiding bending loads. Stiffness provided by the tension network enables a reduced link cross section and a smaller overall  packaged device. When packaged for launch (middle of Fi gure 3) the spreaders slide in between the links  allowing their maximum length to approach the length of the links without requiring any additional  407