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Small Satellites
A small satellite, miniaturized satellite, or smallsat is a satellite of low mass and size, usually under . While all such satellites can be referred to as "small", different classifications are used to categorize them based on mass. Satellites can be built small to reduce the large economic cost of launch vehicles and the costs associated with construction. Miniature satellites, especially in large numbers, may be more useful than fewer, larger ones for some purposes – for example, gathering of scientific data and radio relay. Technical challenges in the construction of small satellites may include the lack of sufficient power storage or of room for a propulsion system. Rationales One rationale for miniaturizing satellites is to reduce the cost; heavier satellites require larger rockets with greater thrust that also have greater cost to finance. In contrast, smaller and lighter satellites require smaller and cheaper launch vehicles and can sometimes be launched in mult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medium Earth Orbit
A medium Earth orbit (MEO) is an geocentric orbit, Earth-centered orbit with an altitude above a low Earth orbit (LEO) and below a high Earth orbit (HEO) – between above sea level.''Catalog of Earth Satellite Orbits'' NASA Earth Observatory. 4 September 2009. Accessed 2 May 2021. The boundary between MEO and LEO is an arbitrary altitude chosen by accepted convention, whereas the boundary between MEO and HEO is the particular altitude of a geosynchronous orbit, in which a satellite takes 24 hours to circle the Earth, the same period as the Earth’s own rotation. All satellites in MEO have an orbital period of less than 24 hours, with the minimum period (for a circular orbit at the lowest MEO altitude) about 2 hours. Satellites in MEO or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picard (satellite)
PICARD is a satellite dedicated to the simultaneous measurement of the absolute total and spectral solar irradiance, the diameter and solar shape, and to the Sun's interior probing by the helioseismology method. These measurements obtained throughout the mission allow study of their variations as a function of solar activity. It launched, along with the Prisma spacecraft, on 15 June 2010 on a Dnepr launcher from Dombarovskiy Cosmodrome, near Yasny, Russia. The mission, originally planned for two years, ended on 4 April 2014. Objectives The objectives of the PICARD mission are to improve our knowledge of: * the functioning of our star through new observations, * the influence of the solar activity on the climate of the Earth. History The PICARD mission was named after the French astronomer of the 17th century Jean Picard (1620–1682) who achieved the first accurate measurements of the solar diameter. These measurements are especially important as they were made during a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasol (satellite)
PARASOL (Polarization & Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) was a French-built Earth observing research satellite. It carried an instrument called POLDER, which studied the radiative and microphysical properties of clouds and aerosols. PARASOL was launched from the French spaceport in Kourou, French Guiana on December 18, 2004, by an Ariane 5 G+. It flew in formation in the " A Train" constellation with several other satellites ( Aqua, CALIPSO, CloudSat and Aura). These satellites had, for the first time ever, combined a full suite of instruments for observing clouds and aerosols, from passive radiometers to active lidar and radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ... sounders. On 2 December 2009, PARASO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Essaim (satellite)
Essaim (''swarm'', in French) was a French military reconnaissance microsatellite constellation. Its main purpose was to collect and map signals intelligence around the world. The Direction générale de l'armement (DGA) described it as a "vacuum cleaner for adiowaves". Description Essaim was a constellation of four 120 kg microsatellites (one of which was a spare) in low Earth orbit (LEO). They were demonstration models which were supposed to last three years. They flew separated by a few hundreds of kilometers. Missions were designed by the ''Celar'' (Centre d'électronique de l'armement) in Bruz, near Rennes and were uploaded from CNES in Toulouse to the constellation. Collected data followed the same path in reverse order. Launch The constellation was launched from Kourou, in French Guiana, by an Ariane 5 G+ launch vehicle on 18 December 2004. The flight was shared with Helios 2A and two other auxiliary payloads: Parasol An umbrella or parasol is a folding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demeter (satellite)
DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) was a French micro-satellite operated by CNES devoted to the investigation of the ionospheric disturbances due to seismic and volcanic activity. It was launched on June 29, 2004, on a quasi Sun-synchronous circular orbit with an inclination of about 98.23° and an altitude of about 710 km. The altitude was changed to about 660 km in December 2005. Due to the specific orbit, DEMETER was always located either shortly before the local noon (10:30 local time) or local midnight (22:30 local time). The satellite performs 14 orbits per day and measures continuously between -65° and +65° of invariant latitude. DEMETER observed an increase in ultra low frequency radio waves in the month before the 2010 Haiti earthquake. During the 2010 eruption of Mount Merapi, DEMETER noted anomalies in the ionosphere. Scientific operations ended December 9, 2010. Scientific Objectives * To study ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wet Mass
In aerospace engineering, mass ratio is a measure of the efficiency of a rocket. It describes how much more massive the vehicle is with propellant than without; that is, the ratio of the rocket's ''wet mass'' (vehicle plus contents plus propellant) to its ''dry mass'' (vehicle plus contents). A more efficient rocket design requires less propellant to achieve a given goal, and would therefore have a lower mass ratio; however, for any given efficiency a higher mass ratio typically permits the vehicle to achieve higher delta-v. The mass ratio is a useful quantity for back-of-the-envelope rocketry calculations: it is an easy number to derive from either \Delta or from rocket and propellant mass, and therefore serves as a handy bridge between the two. It is also a useful for getting an impression of the size of a rocket: while two rockets with mass fractions of, say, 92% and 95% may appear similar, the corresponding mass ratios of 12.5 and 20 clearly indicate that the latter syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Technology 5 On Payload Structure
Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as ''spacetime''. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. In the 19th and 20th centuries mathematicians began to examine geometries that are non-Euclidean, in which space is conceived as '' curved'', rather than '' flat'', as in the Euclidean space. According to Albert Einstein's theory of general relativity, space around gravitational fields deviates from Euclidean space. Experimental tests of general relativity have confirmed that non-Euclidean geometries provide a better model ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tel Aviv University
Tel Aviv University (TAU) is a Public university, public research university in Tel Aviv, Israel. With over 30,000 students, it is the largest university in the country. Located in northwest Tel Aviv, the university is the center of teaching and research of the city, comprising 9 faculties, 17 teaching hospitals, 18 performing arts centers, 27 schools, 106 departments, 340 research centers, and 400 laboratories. Tel Aviv University originated in 1956 when three education units merged to form the university. The original campus was expanded and now makes up in Tel Aviv's Ramat Aviv neighborhood. History TAU's origins date back to 1956, when three research institutes: the Tel Aviv School of Law and Economics (established in 1935), the Institute of Natural Sciences (established in 1931), and the Academic Institute of Jewish Studies (established in 1954) – joined to form Tel Aviv University. Initially operated by the Tel Aviv municipality, the university was granted autonomy in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Israel
Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Israeli-occupied territories, It occupies the Occupied Palestinian territories, Palestinian territories of the West Bank in the east and the Gaza Strip in the south-west. Israel also has a small coastline on the Red Sea at its southernmost point, and part of the Dead Sea lies along its eastern border. Status of Jerusalem, Its proclaimed capital is Jerusalem, while Tel Aviv is the country's Gush Dan, largest urban area and Economy of Israel, economic center. Israel is located in a region known as the Land of Israel, synonymous with the Palestine (region), Palestine region, the Holy Land, and Canaan. In antiquity, it was home to the Canaanite civilisation followed by the History of ancient Israel and Judah, kingdoms of Israel and Judah. Situate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technion – Israel Institute Of Technology
The Technion – Israel Institute of Technology is a public university, public research university located in Haifa, Israel. Established in 1912 by Jews under the dominion of the Ottoman Empire, the Technion is the oldest university in the country. The university offers degrees in science and engineering, and related fields such as architecture, medicine, industrial management, and education. It has 19 academic departments, 60 research centers, and 12 affiliated teaching hospitals. Since its founding, it has awarded more than 123,000 degrees and its graduates are cited for providing the skills and education behind the creation and protection of the State of Israel. Technion's 565 faculty members include three Nobel laureates in Chemistry, Nobel Laureates in chemistry. Four Nobel Laureates, Nobel laureates have been associated with the university. The current List of presidents of the Technion, president of the Technion is Uri Sivan. The selection of Modern Hebrew, Hebrew as th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomous Nanosatellites
In developmental psychology and moral, political, and bioethical philosophy, autonomy is the capacity to make an informed, uncoerced decision. Autonomous organizations or institutions are independent or self-governing. Autonomy can also be defined from a human resources perspective, where it denotes a (relatively high) level of discretion granted to an employee in his or her work. In such cases, autonomy is known to generally increase job satisfaction. Self-actualized individuals are thought to operate autonomously of external expectations. In a medical context, respect for a patient's personal autonomy is considered one of many fundamental ethical principles in medicine. Sociology In the sociology of knowledge, a controversy over the boundaries of autonomy inhibited analysis of any concept beyond relative autonomy, until a typology of autonomy was created and developed within science and technology studies. According to it, the institution of science's existing autonomy i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
