Solar conjunction generally occurs when a

planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...

or other

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

object is on the opposite side of the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

from the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. From an Earth reference, the Sun will pass between the Earth and the object. Communication with any

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

in solar conjunction will be severely limited due to the Sun's interference on radio transmissions from the spacecraft. The term can also refer to the passage of the line of sight to an interior planet ( Mercury or

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

) or comet being very close to the solar disk. If the planet passes directly in front of the Sun, a solar transit occurs.

Spacecraft-related issues

There is also a risk that an antenna equipped with auto-tracking will begin following the Sun's movements instead of the satellite once they are no longer inline with each other. This is because the Sun acts as a large electromagnetic noise generator which creates a signal much stronger than the satellite's tracking signal. One example of limitations caused by the solar conjunction occurred when the

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

- JPL team put the

Curiosity rover ''Curiosity'' is a car-sized Mars rover Space exploration, exploring Gale (crater), Gale crater and Mount Sharp on Mars as part of NASA's Mars Science Laboratory (MSL) mission. ''Curiosity'' was launched from Cape Canaveral Space Force Station ...

on Mars' surface in

autonomous In developmental psychology and moral, political, and bioethical philosophy, autonomy is the capacity to make an informed, uncoerced decision. Autonomous organizations or institutions are independent or self-governing. Autonomy can also be defi ...

operation mode for 25 days during the conjunction. In autonomous mode

Curiosity Curiosity (from Latin , from "careful, diligent, curious", akin to "care") is a quality related to inquisitive thinking, such as exploration, investigation, and learning, evident in humans and other animals. Curiosity helps Developmental psyc ...

suspends all movements and active science operations but retains communication-independent experiments (e.g. record atmospheric and radiation data). A more recent example occurred with the Mars rover Perseverance in October 2021.

References

Astrological aspects Conjunctions (astronomy and astrology) Satellite broadcasting Spaceflight concepts {{sun-stub

Spacecraft-related issues

See also

References