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Lander (spacecraft)
A lander is a spacecraft that descends towards, then comes to rest on the surface of an astronomical body other than Earth. In contrast to an impact probe, which makes a hard landing that damages or destroys the probe upon reaching the surface, a lander makes a soft landing after which the probe remains functional. For bodies with atmospheres, the landing occurs after atmospheric entry. In these cases, landers may employ parachutes to slow them down enough to maintain a low terminal velocity. In some cases, small landing rockets will be fired just before impact in order to reduce the lander's velocity. Landing may be accomplished by controlled descent and set down on landing gear, with the possible addition of a post-landing attachment mechanism (such as the mechanism used by ''Philae'') for celestial bodies with low gravity. Some missions (for example, Luna 9 and Mars Pathfinder) used inflatable airbags to cushion the lander's impact rather than utilizing more traditional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Viking 2
The ''Viking 2'' mission was part of the American Viking program to Mars, and consisted of an orbiter and a lander essentially identical to that of the '' Viking 1'' mission. ''Viking 2'' was operational on Mars for sols ( days; '). The ''Viking 2'' lander operated on the surface for days, or sols, and was turned off on April 12, 1980, when its batteries eventually failed. The orbiter worked until July 25, 1978, returning almost 16,000 images in 706 orbits around Mars. Mission profile The craft was launched on September 9, 1975. Following launch using a Titan/Centaur launch vehicle and a 333-day cruise to Mars, the ''Viking 2'' Orbiter began returning global images of Mars prior to orbit insertion. The orbiter was inserted into a 1,500 x 33,000 km, 24.6 h Mars orbit on August 7, 1976, and trimmed to a 27.3 h site certification orbit with a periapsis of 1,499 km and an inclination of 55.2 degrees on August 9. The orbiter then began taking photographs of candidate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Atmospheric Reentry
Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entry,'' as in the entry of astronomical objects, space debris, or bolides. It may be ''controlled entry'' (or ''reentry'') of a spacecraft that can be navigated or follow a predetermined course. Methods for controlled atmospheric ''entry, descent, and landing'' of spacecraft are collectively termed as ''EDL''. Objects entering an atmosphere experience Drag (physics), atmospheric drag, which puts mechanical stress on the object, and aerodynamic heating—caused mostly by compression of the air in front of the object, but also by drag. These forces can cause loss of mass (ablation) or even complete disintegration of smaller objects, and objects with lower compressive strength can explode. Objects have reentered with speeds ranging from 7.8&n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type asteroid, C-type (carbonaceous), M-type asteroid, M-type (metallic), or S-type asteroid, S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres (dwarf planet), Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 astronomical unit, AU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Titan (moon)
Titan is the largest moon of Saturn and the List of Solar System objects by size, second-largest in the Solar System. It is the only Natural satellite, moon known to have an atmosphere denser than the Atmosphere of Earth, Earth's and is the only known object in space—other than Earth—on which there is clear evidence that stable bodies of liquid exist. Titan is one of seven List of gravitationally rounded objects of the Solar System, gravitationally rounded moons of Saturn and the second-most distant among them. Frequently described as a Planetary-mass moon, planet-like moon, Titan is 50% larger in diameter than Earth's Moon and 80% more Mass, massive. It is the second-largest moon in the Solar System after Jupiter's Ganymede (moon), Ganymede and is larger than Mercury (planet), Mercury; yet Titan is only 40% as massive as Mercury, because Mercury is mainly iron and rock while much of Titan is ice, which is less dense. Discovered in 1655 by the Dutch astronomer Christiaan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mercury (planet)
Mercury is the first planet from the Sun. It is a rocky planet with a trace atmosphere. While it is the List of Solar System objects by size, smallest and least massive planet of the Solar System, its surface gravity is slightly higher than that of Mars. The surface of Mercury is similar to Earth's Moon, heavily Impact crater, cratered, with expansive rupes system, generated from thrust faults, and bright ray systems, formed by ejecta. Its largest crater, Caloris Planitia, has a diameter of , which is about one-third the diameter of the planet (). Being the most inferior planet, inferior orbiting planet it appears in Earth's sky, always close to the Sun, either as a "morning star" or an "evening star". It stays most of the time the closest to all other planets and is the planet with the highest delta-v needed to travel to from all other planets of the Solar System. Mercury's sidereal year (88.0 Earth days) and sidereal day (58.65 Earth days) are in a 3:2 ratio. This relation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, frost, larger polar regions of permafrost and ice caps (with seasonal snow), but no liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. It is half as wide as Earth or twice the Moon, with a diameter of , and has a surface area the size of all the dry land of Earth. Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 and denser than Earth and any other rocky body in the Solar System. Its atmosphere is composed of mostly carbon dioxide (), with a global sulfuric acid cloud cover and no liquid water. At the mean surface level the atmosphere reaches a temperature of and a pressure 92 times greater than Earth's at sea level, turning the lowest layer of the atmosphere into a supercritical fluid. Venus is the third brightest object in Earth's sky, after the Moon and the Sun, and, like Mercury, appears always relatively close to the Sun, either as a "morning star" or an "evening star", resulting from orbiting closer ( inferior) to the Sun than Earth. The orbits of Venus and Earth make the two planets approach each other in synodic periods of 1.6 years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar day) that is synchronized to its orbital period (Lunar month#Synodic month, lunar month) of 29.5 Earth days. This is the product of Earth's gravitation having tidal forces, tidally pulled on the Moon until one part of it stopped rotating away from the near side of the Moon, near side, making always the same lunar surface face Earth. Conversley, the gravitational pull of the Moon, on Earth, is the main driver of Earth's tides. In geophysical definition of planet, geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is , roughly one-quarter of Earth's (about as wide as the contiguous United States). Within the Solar System, it is the List of Solar System objects by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Terrestrial Planet
A terrestrial planet, tellurian planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate, rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Venus, Earth and Mars. Among astronomers who use the geophysical definition of a planet, two or three planetary-mass satellites – Earth's Moon, Io, and sometimes Europa – may also be considered terrestrial planets. The large rocky asteroids Pallas and Vesta are sometimes included as well, albeit rarely. The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth (''Terra'' and ''Tellus''), as these planets are, in terms of structure, ''Earth-like''. Terrestrial planets are generally studied by geologists, astronomers, and geophysicists. Terrestrial planets have a solid planetary surface, making them substantially different from larger gaseous planets, which are composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mars Pathfinder
''Mars Pathfinder'' was an American robotic spacecraft that landed a base station with a rover (space exploration), roving probe on Mars in 1997. It consisted of a Lander (spacecraft), lander, renamed the Carl Sagan Memorial Station, and a lightweight, wheeled robotic Mars rover named ''Sojourner (rover), Sojourner'', the first rover to operate outside the Earth–Moon system. The mission terminated in 1998. Launched on December 4, 1996, by NASA aboard a Delta II booster a month after the ''Mars Global Surveyor'', it landed on July 4, 1997, on Mars's Ares Vallis, in a region called Chryse Planitia in the Oxia Palus quadrangle. The lander (spacecraft), lander then opened, exposing the rover which conducted many experiments on the Martian surface. The mission carried a series of scientific instruments to analyze the Martian Celestial body atmosphere, atmosphere, climate, and geology and the composition of its rock (geology), rocks and soil. It was the second project from NASA's D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Philae (spacecraft)
''Philae'' ( or ) was a robotic European Space Agency Lander (spacecraft), lander that accompanied the Rosetta (spacecraft), ''Rosetta'' spacecraft until it separated to land on comet 67P/Churyumov–Gerasimenko, ten years and eight months after departing Earth. On 12 November 2014, ''Philae'' touched down on the comet, but it bounced when its anchoring harpoons failed to deploy and a thruster designed to hold the probe to the surface did not fire. After bouncing off the surface twice, ''Philae'' achieved the first-ever "soft" (nondestructive) landing on a comet nucleus, although the lander's final, uncontrolled touchdown left it in a non-optimal location and orientation. Despite the landing problems, the probe's instruments obtained the first images from a comet's surface. Several of the instruments on ''Philae'' made the first in-situ analysis of a comet nucleus, sending back data regarding the composition of the surface and outgassing from the subsurface. In October 2020, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Spacecraft Lander Landing Gear
A spacecraft is a vehicle that is designed to fly and operate in outer space. Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle (carrier rocket). On a sub-orbital spaceflight, a space vehicle enters space and then returns to the surface without having gained sufficient energy or velocity to make a full Earth orbit. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies. Spacecraft used for human spaceflight carry people on board as crew or passengers from start or on orbit (space stations) only, whereas those used for robotic space missions operate either autonomously or telerobotically. Robotic spacecraft used to support scientific research are space probes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
