ExpertGlossary

• The atmospheric shell extending from the top of the mesosphere to outer space; it is a region of more or less steadily increasing temperature with height, starting at 40 to 50 miles (70 to 80 kilometers); the thermosphere includes, therefore, the exosphere and most or all of the ionosphere.
  DoD Missile Defense Agency - Cite This Source - This Definition
• Browse Related Terms: Deep Space (DS), Earth Limb, SKKP, terminator, Visibility Range (or Visibility)

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