occurs when a planet
or other solar system
object is on the opposite side of the sun
from the Earth
. From an Earth reference, the object will pass behind the sun. Communication with any spacecraft
in solar conjunction will be severely limited due to the sun's blocking radio transmissions from the spacecraft. When in reference to Satellite Communications, solar conjunction occurs when the sun is directly in line with orbiting Satellite and the terrestrial receiving station.
The term can also refer to the passage of the line of sight to an interior planet (Mercury or Venus) being very close to the solar disk. If the planet passes directly in front of the sun, a solar transit occurs.