Leather part for their skins. Kangaroo leather is used to make items that must be strong and flexible. It is the material most commonly used in bullwhips. Some motorcyclists favor kangaroo leather for motorcycle leathers because of its light weight and abrasion resistance. Kangaroo leather is also used for falconry jesses, soccer footwear, and boxing speed bags. Although originally raised for their feathers in the 19th century, ostriches are now more popular for both meat and leather. Ostrich leather has a characteristic "goose bump" look because of the large follicles where the feathers grew. Different processes produce different finishes for many
Space tether that scale). For some applications, the tensile force on the tether is projected to be less than 15 lbs (< 65 N) Material selection in this case depends on the purpose of the mission and design constraints. Electrodynamic tethers, such as the one used on TSS-1R, may use thin copper wires for high conductivity (see EDT). There are design equations for certain applications that may be used to aid designers in identifying typical quantities that drive material selection. Space elevator equations typically use a "characteristic length", L, which is also known as its "self-support length" and is the length of