|
Queqiao
''Queqiao'' relay satellite (), also known as the Chang'e 4 Relay, is a communications relay and radio astronomy satellite for the Chang'e 4 lunar farside mission. As part of the Chinese Lunar Exploration Program, the China National Space Administration (CNSA) launched the Queqiao relay satellite on 20 May 2018 to a halo orbit around the Earth–Moon L2 Lagrangian point Queqiao is the first ever communication relay and radio astronomy satellite at this location. The name ''Queqiao'' ("Magpie Bridge") was inspired by and came from the Chinese tale '' The Cowherd and the Weaver Girl''. Design and development Queqiao was designed to function as a communication relay for the Chang'e 4 mission to the far side of the Moon, as well as a deep space radio astronomy observatory for the Chinese space program. Direct communication with Earth is impossible on the far side of the Moon, since transmissions are blocked by the Moon. Communications must go through a communications relay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queqiao Antenna
''Queqiao'' relay satellite (), also known as the Chang'e 4 Relay, is a communications relay and radio astronomy satellite for the Chang'e 4 lunar farside mission. As part of the Chinese Lunar Exploration Program, the China National Space Administration (CNSA) launched the Queqiao relay satellite on 20 May 2018 to a halo orbit around the Earth–Moon L2 Lagrangian point Queqiao is the first ever communication relay and radio astronomy satellite at this location. The name ''Queqiao'' ("Magpie Bridge") was inspired by and came from the Chinese tale '' The Cowherd and the Weaver Girl''. Design and development Queqiao was designed to function as a communication relay for the Chang'e 4 mission to the far side of the Moon, as well as a deep space radio astronomy observatory for the Chinese space program. Direct communication with Earth is impossible on the far side of the Moon, since transmissions are blocked by the Moon. Communications must go through a communications relay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chang'e 4
Chang'e 4 (; ) is a robotic spacecraft mission, part of the second phase of the Chinese Lunar Exploration Program. China achieved humanity's first soft landing on the far side of the Moon, on 3 January 2019. A communication relay satellite, , was first launched to a halo orbit near the Earth–Moon L2 point in May 2018. The robotic lander and ''Yutu-2'' () rover were launched on 7 December 2018 and entered lunar orbit on 12 December 2018, before landing on the Moon's far side. The mission is the follow-up to Chang'e 3, the first Chinese landing on the Moon. The spacecraft was originally built as a backup for Chang'e 3 and became available after Chang'e 3 landed successfully in 2013. The configuration of Chang'e 4 was adjusted to meet new scientific and performance objectives. Like its predecessors, the mission is named after Chang'e, the Chinese Moon goddess. In November 2019, Chang’e 4 mission team was awarded Gold Medal by the Royal Aeronautical Society. In October ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Lunar Exploration Program
The Chinese Lunar Exploration Program (CLEP; ), also known as the Chang'e Project () after the Chinese moon goddess Chang'e, is an ongoing series of robotic Moon missions by the China National Space Administration (CNSA). The program incorporates lunar orbiters, landers, rovers and sample return spacecraft, launched using Long March rockets. Launches and flights are monitored by a telemetry, tracking, and command (TT&C) system, which uses radio antennas in Beijing and antennas in Kunming, Shanghai, and Ürümqi to form a VLBI antenna. A proprietary ground application system is responsible for downlink data reception. Ouyang Ziyuan, a geologist, chemical cosmologist, and the program's chief scientist, was among the first to advocate the exploitation not only of known lunar reserves of metals such as titanium, but also of helium-3, an ideal fuel for future nuclear fusion power plants. Ye Peijian serves as the program's chief commander and chief designer. Scientist Sun Jia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Space Program
The space program of the People's Republic of China is directed by the China National Space Administration (CNSA). China's space program has overseen the development and launch of ballistic missiles, thousands of artificial satellites, manned spaceflight, an indigenous space station, and has stated plans to explore the Moon, Mars, and the broader Solar System. The technological roots of the Chinese space program trace back to the 1950s, when, with the help of the newly-allied Soviet Union, China began development of its first ballistic missile and rocket programs in response to the perceived American (and, later, Soviet) threats.DF-1 . Driven by the successes of Sovi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halo Orbit
A halo orbit is a periodic, three-dimensional orbit near one of the L1, L2 or L3 Lagrange points in the three-body problem of orbital mechanics. Although a Lagrange point is just a point in empty space, its peculiar characteristic is that it can be orbited by a Lissajous orbit or a halo orbit. These can be thought of as resulting from an interaction between the gravitational pull of the two planetary bodies and the Coriolis and centrifugal force on a spacecraft. Halo orbits exist in any three-body system, e.g., a Sun–Earth–orbiting satellite system or an Earth–Moon–orbiting satellite system. Continuous "families" of both northern and southern halo orbits exist at each Lagrange point. Because halo orbits tend to be unstable, stationkeeping may be required to keep a satellite on the orbit. Most satellites in halo orbit serve scientific purposes, for example as space telescopes. Definition and history Robert W. Farquhar first used the name "halo" in 1966 for orbits arou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halo Orbit
A halo orbit is a periodic, three-dimensional orbit near one of the L1, L2 or L3 Lagrange points in the three-body problem of orbital mechanics. Although a Lagrange point is just a point in empty space, its peculiar characteristic is that it can be orbited by a Lissajous orbit or a halo orbit. These can be thought of as resulting from an interaction between the gravitational pull of the two planetary bodies and the Coriolis and centrifugal force on a spacecraft. Halo orbits exist in any three-body system, e.g., a Sun–Earth–orbiting satellite system or an Earth–Moon–orbiting satellite system. Continuous "families" of both northern and southern halo orbits exist at each Lagrange point. Because halo orbits tend to be unstable, stationkeeping may be required to keep a satellite on the orbit. Most satellites in halo orbit serve scientific purposes, for example as space telescopes. Definition and history Robert W. Farquhar first used the name "halo" in 1966 for orbits arou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chang'e 2
Chang'e 2 (; ) is a Chinese unmanned lunar probe that was launched on 1 October 2010. It was a follow-up to the Chang'e 1 lunar probe, which was launched in 2007. Chang'e 2 was part of the first phase of the Chinese Lunar Exploration Program, and conducted research from a 100-km-high lunar orbit in preparation for the December 2013 soft landing by the Chang'e 3 lander and rover. Chang'e 2 was similar in design to Chang'e 1, although it featured some technical improvements, including a more advanced onboard camera. Like its predecessor, the probe was named after Chang'e, an ancient Chinese moon goddess. After completing its primary objective, the probe left lunar orbit for the Earth–Sun Lagrangian point, to test the Chinese tracking and control network, making the China National Space Administration the third space agency after NASA and ESA to have visited this point. It entered orbit around L2 on 25 August 2011, and began transmitting data from its new position in September 201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long March 4C
The Long March 4C, also known as the Chang Zheng 4C, CZ-4C and LM-4C, previously designated Long March 4B-II, is a Chinese orbital launch vehicle. It is launched from the Jiuquan, Taiyuan, and Xichang Satellite Launch Centers, and consists of 3 stages. Long March 4C vehicles have been used to launch the Yaogan-1, Yaogan-3 synthetic-aperture radar (SAR) satellites and the Fengyun-3A polar orbiting meteorological satellite. On 15 December 2009, a Long March 4C was used to launch Yaogan-8. Because it was still designated as Long March 4B-II at the time of its maiden flight, the first launch is often mistaken for a Long March 4B. The Long March 4C is derived from the Long March 4B, but features a restartable upper stage, and a larger payload fairing. On 1 September 2016, the Long March 4C failed for reasons not yet known. A Long March 4C rocket blasted off from the Taiyuan Satellite Launch Center in Shanxi but failed to insert its payload, the Gaofen 10 satellite, into its desi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagrange Point
In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of the restricted three-body problem in which two bodies are far more massive than the third. Normally, the two massive bodies exert an unbalanced gravitational force at a point, altering the orbit of whatever is at that point. At the Lagrange points, the gravitational forces of the two large bodies and the centrifugal force balance each other. This can make Lagrange points an excellent location for satellites, as few orbit corrections are needed to maintain the desired orbit. Small objects placed in orbit at Lagrange points are in equilibrium in at least two directions relative to the center of mass of the large bodies. For any combination of two orbital bodies there are five Lagrange points, L1 to L5, all in the orbital plane of the two lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Cowherd And The Weaver Girl
"The Cowherd and the Weaver Girl" are characters found in Chinese mythology and characters appearing eponymously in a romantic Chinese folk tale. The story tells of the romance between Zhinü (; the weaver girl, symbolizing the star Vega) and Niulang (; the cowherd, symbolizing the star Altair). Their love was not allowed, and thus they were banished to opposite sides of the heavenly river (symbolizing the Milky Way). Once a year, on the seventh day of the seventh lunar month, a flock of magpies would form a bridge to reunite the lovers for a single day. Though there are many variations of the story, the earliest-known reference to this famous myth dates back to a poem from the Classic of Poetry from over 2600 years ago. "The Cowherd and the Weaver Girl" originated from people’s worship of natural celestial phenomena, and later developed into the Qixi Festival since the Han Dynasty. It has also been celebrated as the Tanabata festival in Japan and the Chilseok festival in K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lissajous Orbit
In orbital mechanics, a Lissajous orbit (), named after Jules Antoine Lissajous, is a quasi-periodic orbital trajectory that an object can follow around a Lagrangian point of a three-body system without requiring any propulsion. Lyapunov orbits around a Lagrangian point are curved paths that lie entirely in the plane of the two primary bodies. In contrast, Lissajous orbits include components in this plane and perpendicular to it, and follow a Lissajous curve. Halo orbits also include components perpendicular to the plane, but they are periodic, while Lissajous orbits are usually not. In practice, any orbits around Lagrangian points , , or are dynamically unstable, meaning small departures from equilibrium grow over time. As a result, spacecraft in these Lagrangian point orbits must use their propulsion systems to perform orbital station-keeping. Although they are not perfectly stable, a modest effort of station keeping keeps a spacecraft in a desired Lissajous orbit for a long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagrangian Points
In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of the restricted three-body problem in which two bodies are far more massive than the third. Normally, the two massive bodies exert an unbalanced gravitational force at a point, altering the orbit of whatever is at that point. At the Lagrange points, the gravitational forces of the two large bodies and the centrifugal force balance each other. This can make Lagrange points an excellent location for satellites, as few orbit corrections are needed to maintain the desired orbit. Small objects placed in orbit at Lagrange points are in equilibrium in at least two directions relative to the center of mass of the large bodies. For any combination of two orbital bodies there are five Lagrange points, L1 to L5, all in the orbital plane of the two lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
