|
Safe Mode In Spacecraft
Safe mode is an operating mode of a modern uncrewed spacecraft during which all non-essential systems are shut down and only essential functions such as thermal management, radio reception and attitude control are active. Safe mode is entered automatically upon the detection of a predefined operating condition or event that may indicate loss of control or damage to the spacecraft. Usually the trigger event is a system failure or detection of operating conditions considered dangerously out of the normal range. Cosmic rays penetrating spacecraft electrical systems can create false signals or commands and thus cause a trigger event. The central processor electronics are especially prone to such events. Another trigger is the lack of a received command within a given time window. Lack of received commands can be caused by hardware failures or mis-programming of the spacecraft, as in the case of the Viking 1 lander. The process of entering safe mode, sometimes referred to as ''safing' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 satellite, meteorology, navigation, space colonization, Planetary science, planetary exploration, and Space transport, transportation of Human spaceflight, humans and cargo spacecraft, 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 Geocentric orbit, Earth orbit. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other Astronomical object, celestial bodies. Spacecraft used for human spaceflight carry people on board as crew or passengers from start or on orbit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Exploration Rover
NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, ''Spirit (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rover (space exploration), rovers to explore the Martian surface and Geology of Mars, geology; both landed on Mars at separate locations in January 2004. Both rovers far outlived their planned missions of 90 Timekeeping on Mars#Sols, Martian solar days: MER-A ''Spirit'' was active until March 22, 2010, while MER-B ''Opportunity'' was active until June 10, 2018. Objectives The mission's scientific objective was to search for and characterize a wide range of rock (geology), rocks and soils that hold clues to past Water on Mars, water activity on Mars. The mission is part of NASA's Mars Exploration Program, which includes three previous successful landers: the two Viking program landers in 1976 and Mars Pathfinder probe in 1997. The scientific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington Post
''The Washington Post'', locally known as ''The'' ''Post'' and, informally, ''WaPo'' or ''WP'', is an American daily newspaper published in Washington, D.C., the national capital. It is the most widely circulated newspaper in the Washington metropolitan area and has a national audience. As of 2023, the ''Post'' had 130,000 print subscribers and 2.5 million digital subscribers, both of which were the List of newspapers in the United States, third-largest among U.S. newspapers after ''The New York Times'' and ''The Wall Street Journal''. The ''Post'' was founded in 1877. In its early years, it went through several owners and struggled both financially and editorially. In 1933, financier Eugene Meyer (financier), Eugene Meyer purchased it out of bankruptcy and revived its health and reputation; this work was continued by his successors Katharine Graham, Katharine and Phil Graham, Meyer's daughter and son-in-law, respectively, who bought out several rival publications. The ''Post ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Maneuver
In spaceflight, an orbital maneuver (otherwise known as a burn) is the use of propulsion systems to change the orbit of a spacecraft. For spacecraft far from Earth, an orbital maneuver is called a ''deep-space maneuver (DSM)''. When a spacecraft is not conducting a maneuver, especially in a transfer orbit, it is said to be ''coasting''. General Rocket equation The Tsiolkovsky rocket equation, or ideal rocket equation, can be useful for analysis of maneuvers by vehicles using rocket propulsion. A rocket applies acceleration to itself (a thrust) by expelling part of its mass at high speed. The rocket itself moves due to the conservation of momentum. Delta-v The applied change in velocity of each maneuver is referred to as delta-v (\Delta\mathbf\,). The delta-v for all the expected maneuvers are estimated for a mission are summarized in a delta-v budget. With a good approximation of the delta-v budget designers can estimate the propellant required for planned maneuve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juno (spacecraft)
''Juno'' is a NASA space probe orbiting the planet Jupiter. Built by Lockheed Martin Space Systems, Lockheed Martin and operated by NASA Jet Propulsion Laboratory, the spacecraft was launched from Cape Canaveral Air Force Station on August 5, 2011 UTC, as part of the New Frontiers program. ''Juno'' entered a polar orbit of Jupiter on July 5, 2016, UTC, to begin a scientific investigation of the planet. After completing its mission, ''Juno'' was originally planned to be intentionally deorbited into Jupiter's atmosphere, but has since been approved to continue orbiting until contact is lost with the spacecraft. ''Juno'' mission is to measure Jupiter's composition, gravity field, gravitational field, magnetic field, and Magnetosphere of Jupiter, polar magnetosphere. It also searches for clues about how the planet formed, including whether it has a rocky core, the amount of water present within the deep atmosphere, mass distribution, and its deep winds, which can reach speeds up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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's civil list of government space agencies, space program, aeronautics research and outer space, space research. National Aeronautics and Space Act, Established in 1958, it succeeded the National Advisory Committee for Aeronautics (NACA) to give the American space development effort a distinct civilian orientation, emphasizing peaceful applications in space science. It has since led most of America's space exploration programs, including Project Mercury, Project Gemini, the 1968–1972 Apollo program missions, the Skylab space station, and the Space Shuttle. Currently, NASA supports the International Space Station (ISS) along with the Commercial Crew Program and oversees the development of the Orion (spacecraft), Orion spacecraft and the Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Race Condition
A race condition or race hazard is the condition of an electronics, software, or other system where the system's substantive behavior is dependent on the sequence or timing of other uncontrollable events, leading to unexpected or inconsistent results. It becomes a bug when one or more of the possible behaviors is undesirable. The term ''race condition'' was already in use by 1954, for example in David A. Huffman's doctoral thesis "The synthesis of sequential switching circuits". Race conditions can occur especially in logic circuits or multithreaded or distributed software programs. Using mutual exclusion can prevent race conditions in distributed software systems. In electronics A typical example of a race condition may occur when a logic gate combines signals that have traveled along different paths from the same source. The inputs to the gate can change at slightly different times in response to a change in the source signal. The output may, for a brief period, chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pluto
Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun. It is the largest known trans-Neptunian object by volume by a small margin, but is less massive than Eris (dwarf planet), Eris. Like other Kuiper belt objects, Pluto is made primarily of ice and rock and is much smaller than the inner planets. Pluto has roughly one-sixth the mass of the Moon and one-third its volume. Originally considered a planet, its classification was changed when astronomers adopted a new definition of planet, definition of ''planet''. Pluto has a moderately Orbital eccentricity, eccentric and Inclination, inclined orbit, ranging from from the Sun. Light from the Sun takes 5.5 hours to reach Pluto at its orbital distance of . Pluto's eccentric orbit periodically brings it closer to the Sun than Neptune, but a stabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
MESSENGER
Messenger, Messengers, The Messenger or The Messengers may refer to: People * Courier, a person or company that delivers messages, packages, or mail * Messenger (surname) * Bicycle messenger, a bicyclist who transports packages through cities * Messenger-at-arms, an officer of the Scottish Court of Session * Messenger of the Court, a court officer responsible for carrying communications and executing other orders * Prophets and messengers in Islam * Muhammad and other prophets in Islam, who were known as Messengers of Allah (God) Science and technology Biology and chemistry * Chemical messenger, such as a hormone or neurotransmitter, a molecule used for cellular signalling * Messenger RNA (mRNA), RNA that carries information from DNA to the ribosome sites of protein synthesis in a cell Electronics and computing *Instant messenger, a tool for online text communication **Facebook Messenger, an instant messaging service by Meta (Facebook) **Microsoft Messenger service, an instant me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
