page_title: Space tether
section_title: Mass ratio
hierarchical_section_title: Space tether / Construction / Shape / Mass ratio
caption_attribution_description: English: Diagram of the payload:tether ratio of a spinning bolus (space) tether
context_page_description: Space tethers are long cables which can be used for propulsion, momentum exchange, stabilization and attitude control, or maintaining the relative positions of the components of a large dispersed satellite/spacecraft sensor system. Depending on the mission objectives and altitude, spaceflight using this form of spacecraft propulsion is theorized to be significantly less expensive than spaceflight using rocket engines.
context_section_description: Integrating the area to give the volume and multiplying by the density and dividing by the payload mass gives a payload mass / tether mass ratio of:
  where erf is the normal probability error function.
  Let ,
  then:
  This equation can be compared with the rocket equation, which is proportional to a simple exponent on a velocity, rather than a velocity squared. This difference effectively limits the delta-v that can be obtained from a single tether.
caption: Graph of tether mass to payload ratio versus the tip speed in multiples of the characteristic speed of the material
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