Atmosphere of Mars in the context of "Mars"

The study of extraterrestrial atmospheres is an active field of research, both as an aspect of astronomy and to gain insight into Earth's atmosphere. In addition to Earth, many of the other astronomical objects in the Solar System have atmospheres. These include all the giant planets, as well as Mars, Venus and Titan. Several moons and other bodies also have atmospheres, as do comets and the Sun. There is evidence that extrasolar planets can have an atmosphere. Comparisons of these atmospheres to one another and to Earth's atmosphere broaden our basic understanding of atmospheric processes such as the greenhouse effect, aerosol and cloud physics, and atmospheric chemistry and dynamics.

In September 2022, astronomers were reported to have formed a new group, called "Categorizing Atmospheric Technosignatures" (CATS), to list the results of exoplanet atmosphere studies for biosignatures, technosignatures and related.

The planet Mars has two permanent polar ice caps of water ice and some dry ice (frozen carbon dioxide, CO₂). Above kilometer-thick layers of water ice permafrost, slabs of dry ice are deposited during a pole's winter, lying in continuous darkness, causing 25–30% of the atmosphere being deposited annually at either of the poles. When the poles are again exposed to sunlight, the frozen CO₂ sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds.

The caps at both poles consist primarily of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one meter thick on the north cap in the northern winter, while the south cap has a permanent dry ice cover about 8 m thick. The northern polar cap has a diameter of about 1000 km during the northern Mars summer, and contains about 1.6 million cubic km of ice, which if spread evenly on the cap would be 2 km thick. (This compares to a volume of 2.85 million cubic km (km) for the Greenland ice sheet.) The southern polar cap has a diameter of 350 km and a thickness of 3 km. The total volume of ice in the south polar cap plus the adjacent layered deposits has also been estimated at 1.6 million cubic km. Both polar caps show spiral troughs, which analysis of SHARAD ice penetrating radar has shown are a result of roughly perpendicular katabatic winds that spiral due to the Coriolis Effect.

Crustal magnetism is the magnetic field of the crust of a planetary body. The crustal magnetism of Earth has been studied; in particular, various magnetic crustal anomalies have been studied. Two examples of crustal magnetic anomalies on Earth that have been studied in the Americas are the Brunswick magnetic anomaly (BMA) and East Coast magnetic anomaly (ECMA). Also, there can be a correlation between physical geological features and certain readings from crustal magnetism on Earth. Below the surface of the Earth, the crustal magnetism is lost because the temperature rises above the curie temperature of the materials producing the field.

On Mars, the crustal magnetic fields have been noted as affecting its ionosphere. (See also Atmosphere of Mars) The magnetic fields on Mars from its rocks and crust are thought to come from ferromagnetism and if the material is heated above its curie temperature the magnetic imprint is un-done. The Mars Global Surveyor (MGS) discovered magnetic stripes in the crust of Mars, especially in the Phaethontis and Eridania quadrangles (Terra Cimmeria and Terra Sirenum). The magnetometer on MGS discovered 100 km (62 mi) wide stripes of magnetized crust running roughly parallel for up to 2,000 kilometres (1,200 mi). These stripes alternate in polarity, with the north magnetic pole of one pointing up from the surface and the north magnetic pole of the next pointing down. When similar stripes were discovered on Earth in the 1960s, they were taken as evidence of plate tectonics. Researchers believe these magnetic stripes on Mars are evidence for a short, early period of plate tectonic activity. Only roughly half of Mars seems to have a crustal magnetic field; there are several possible explanations for this, such as that an internal dynamo only affected part of the planet, or that a body struck Mars in the past destroying the magnetism.

Ingenuity, nicknamed Ginny, is an autonomous NASA helicopter that operated on Mars from 2021 to 2024 as part of the Mars 2020 mission. Ingenuity made its first flight on 19 April 2021, demonstrating that flight is possible in the extremely thin atmosphere of Mars, and becoming the first aircraft to conduct a powered and controlled extraterrestrial flight. It was designed by NASA's Jet Propulsion Laboratory (JPL) in collaboration with AeroVironment, NASA's Ames Research Center and Langley Research Center with some components supplied by Lockheed Martin Space, Qualcomm, and SolAero.

Ingenuity was delivered to Mars on 18 February 2021, attached to the underside of the Perseverance rover, which landed at Octavia E. Butler Landing near the western rim of the 45 km-wide (28 mi) Jezero crater. Because radio signals take several minutes to travel between Earth and Mars, it could not be manually controlled in real time, and instead autonomously flew flight plans sent to it by JPL.