Which orbit type provides long dwell times over high latitudes?

Which orbit type provides long dwell times over high latitudes?

• A. LEO
• B. MEO
• C. GEO
• D. HEO

Answer: (D)

Highly elliptical, highly inclined orbits provide long dwell times over high latitudes. In these orbits, the apogee sits up near the polar regions, and the spacecraft moves slowly there, so the ground point under the satellite lingers for a long period as the satellite spends more of its orbit near apogee. This is why Molniya- or Tundra-type designs are used to achieve extended visibility over northern latitudes. By contrast, low or medium Earth orbits pass quickly over any given latitude, and geostationary orbit stays fixed above the equator, not offering extended dwell at high latitudes.

Highly elliptical, highly inclined orbits provide long dwell times over high latitudes. In these orbits, the apogee sits up near the polar regions, and the spacecraft moves slowly there, so the ground point under the satellite lingers for a long period as the satellite spends more of its orbit near apogee. This is why Molniya- or Tundra-type designs are used to achieve extended visibility over northern latitudes. By contrast, low or medium Earth orbits pass quickly over any given latitude, and geostationary orbit stays fixed above the equator, not offering extended dwell at high latitudes.