Exploration of MarsThe planet Mars has been explored remotely by spacecraft. Probes sent from Earth, beginning in the late 20th century, have yielded a large increase in knowledge about the Martian system, focused primarily on understanding its geology and habitability potential. Engineering interplanetary journeys is complicated and the exploration of Mars has experienced a high failure rate, especially the early attempts. Roughly sixty percent of all spacecraft destined for Mars failed before completing their missions and some failed before their observations could begin.
PerchlorateA perchlorate is a chemical compound containing the perchlorate ion, ClO4-, the conjugate base of perchloric acid (ionic perchlorate). As counterions, there can be metal cations, quaternary ammonium cations or other ions, for example, nitronium cation (NO2+). The term perchlorate can also describe perchlorate esters or covalent perchlorates. These are organic compounds that are alkyl or aryl esters of perchloric acid. They are characterized by a covalent bond between an oxygen atom of the ClO4 moiety and an organyl group.
Viking lander biological experimentsIn 1976 two identical Viking program landers each carried four types of biological experiments to the surface of Mars. The first successful Mars landers, Viking 1 and Viking 2, then carried out experiments to look for biosignatures of microbial life on Mars. The landers each used a robotic arm to pick up and place soil samples into sealed test containers on the craft. The two landers carried out the same tests at two places on Mars' surface, Viking 1 near the equator and Viking 2 further north.
Timekeeping on MarsThough no standard exists, numerous calendars and other timekeeping approaches have been proposed for the planet Mars. The most commonly seen in the scientific literature denotes the time of year as the number of degrees on its orbit from the northward equinox, and increasingly there is use of numbering the Martian years beginning at the equinox that occurred April 11, 1955. Mars has an axial tilt and a rotation period similar to those of Earth. Thus, it experiences seasons of spring, summer, autumn and winter much like Earth.
Heat shieldIn engineering, a heat shield is a component designed to protect an object or a human operator from being burnt or overheated by dissipating, reflecting, and/or absorbing heat. The term is most often used in reference to exhaust heat management and to systems for dissipating frictional heat. Heat shields are used most commonly in automotive and aerospace. Heat shields protect structures from extreme temperatures and thermal gradients by two primary mechanisms.
AeroshellAn aeroshell is a rigid heat-shielded shell that helps decelerate and protects a spacecraft vehicle from pressure, heat, and possible debris created by drag during atmospheric entry (see blunt body theory). Its main components consist of a heat shield (the forebody) and a back shell. The heat shield absorbs heat caused by air compression in front of the spacecraft during its atmospheric entry.
Phobos (moon)Phobos (ˈfoʊbɒs; systematic designation: Mars I) is the innermost and larger of the two natural satellites of Mars, the other being Deimos. The two moons were discovered in 1877 by American astronomer Asaph Hall. It is named after Phobos, the Greek god of fear and panic, who is the son of Ares (Mars) and twin brother of Deimos. Phobos is a small, irregularly shaped object with a mean radius of . Phobos orbits from the Martian surface, closer to its primary body than any other known planetary moon.
Sojourner (rover)Sojourner is a robotic Mars rover that landed in the Ares Vallis channel in the Chryse Planitia region of the Oxia Palus quadrangle on July 4, 1997. Sojourner was operational on Mars for 92 sols (95 Earth days). It was the first wheeled vehicle to rove on a planet other than Earth and formed part of the Mars Pathfinder mission. The rover was equipped with front and rear cameras, and hardware that was used to conduct several scientific experiments.
