A satellite or artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life. Methods include monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets, optical observation, and the search for physical artifacts. Attempts to message extraterrestrial intelligences have also been made.
Sputnik 1, sometimes referred to as simply Sputnik, was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for three weeks before its three silver-zinc batteries became depleted. Aerodynamic drag caused it to fall back into the atmosphere on 4 January 1958.
A space telescope is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO-2 launched in 1968, and the Soviet Orion 1 ultraviolet telescope aboard space station Salyut 1 in 1971. Space telescopes avoid several problems caused by the atmosphere, including the absorption or scattering of certain wavelengths of light, obstruction by clouds, and distortions due to atmospheric refraction such as twinkling. Space telescopes can also observe dim objects during the daytime, and they avoid light pollution which ground-based observatories encounter. They are divided into two types: Satellites which map the entire sky, and satellites which focus on selected astronomical objects or parts of the sky and beyond. Space telescopes are distinct from Earth imaging satellites, which point toward Earth for satellite imaging, applied for weather analysis, espionage, and other types of information gathering.
An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, meteorology, cartography and others. The most common type are Earth imaging satellites, that take satellite images, analogous to aerial photographs; some EO satellites may perform remote sensing without forming pictures, such as in GNSS radio occultation.
Twinkling, also called scintillation, is a generic term for variations in apparent brightness, colour, or position of a distant luminous object viewed through a medium. If the object lies outside the Earth's atmosphere, as in the case of stars and planets, the phenomenon is termed astronomical scintillation; for objects within the atmosphere, the phenomenon is termed terrestrial scintillation. As one of the three principal factors governing astronomical seeing, atmospheric scintillation is defined as variations in illuminance only.
James Alfred Van Allen was an American space physicist at the University of Iowa. He was instrumental in establishing the field of magnetospheric research in space.
Landsat 1 (LS-1), formerly named ERTS-A and ERTS-1, was the first satellite of the United States' Landsat program. It was a modified version of the Nimbus 4 meteorological satellite and was launched on July 23, 1972, by a Delta 900 rocket from Vandenberg Air Force Base in California.
Carolyn C. Porco is an American planetary scientist who explores the outer Solar System, beginning with her imaging work on the Voyager missions to Jupiter, Saturn, Uranus and Neptune in the 1980s. She led the imaging science team on the Cassini mission in orbit around Saturn. She is an expert on planetary rings and the Saturnian moon, Enceladus.
Deborah Byrd is an American science journalist. She is editor-in-chief of EarthSky, which presents science news and night sky information. The website served more than 21 million users in 2019, according to Google Analytics.
Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission began in February 2007 as a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles. The name of the mission is an acronym alluding to the Titan Themis.
Satellite Instructional Television Experiment or SITE was an experimental satellite communications project launched in India in 1975, designed jointly by NASA and the Indian Space Research Organization (ISRO). The project made available informational television programs to rural India. The main objectives of the experiment were to educate the financially backward and academically illiterate people of India on various issues via satellite broadcasting, and also to help India gain technical experience in the field of satellite communications.
The Near Earth Object Surveillance Satellite (NEOSSat) is a Canadian microsatellite using a 15-cm aperture f/5.88 Maksutov telescope, with 3-axis stabilisation giving a pointing stability of ~2 arcseconds in a ~100 second exposure. It is funded by the Canadian Space Agency (CSA) and Defence Research and Development Canada (DRDC), and searches for interior-to-Earth-orbit (IEO) asteroids, at between 45 and 55 degree solar elongation and +40 to -40 degrees ecliptic latitude.
StarDate is a science radio program of The University of Texas at Austin McDonald Observatory, broadcast on over 300 radio stations. It is a daily guide to the night sky and breaking astronomical news. Typically heard without formal introduction, StarDate is a self-contained science news feature interwoven with routine radio programming. It is the longest-running science outreach program on U.S. radio.
Space research is scientific study carried out in outer space, and by studying outer space. From the use of space technology to the observable universe, space research is a wide research field. Earth science, materials science, biology, medicine, and physics all apply to the space research environment. The term includes scientific payloads at any altitude from deep space to low Earth orbit, extended to include sounding rocket research in the upper atmosphere, and high-altitude balloons.
Radio Aurora Explorer (RAX) is the first National Science Foundation sponsored CubeSat mission. The RAX mission is a joint effort between SRI International in Menlo Park, California and the University of Michigan in Ann Arbor, Michigan. The chief scientist at SRI International, Dr. Hasan Bahcivan, led his team at SRI to develop the payload while the chief engineer, Dr. James Cutler, led a team of students to develop the satellite bus in the Michigan Exploration Laboratory. There are currently two satellites in the RAX mission.
B. M. Birla Planetarium is a large planetarium in Chennai, India. The fifth B. M. Birla planetarium in the country, it is located at Kotturpuram in the Periyar Science and Technology Centre campus which houses eight galleries, namely, Physical Science, Electronics and Communication, Energy, Life Science, Innovation, Transport, International Dolls and Children and Materials Science, with over 500 exhibits. Built in 1988 in the memory of the great industrialist and visionary of India B. M. Birla, it is considered the most modern planetarium in India, providing a virtual tour of the night sky and holding cosmic shows on a specially perforated hemispherical aluminium inner dome. Other Birla planetariums in India include the M. P. Birla Planetarium in Kolkata, the Birla Planetarium in Hyderabad, and the planetariums in Tiruchirapalli and Coimbatore.
Since its establishment in 1958, NASA has conducted research on a range of topics. Because of its unique structure, work happens at various field centers and different research areas are concentrated in those centers. Depending on the technology, hardware and expertise needed, research may be conducted across a range of centers.
2020 CD3 (also CD3 for short) is a tiny near-Earth asteroid (or minimoon) that ordinarily orbits the Sun but makes close approaches to the Earth–Moon system, in which it can temporarily enter Earth orbit through temporary satellite capture (TSC). It was discovered at the Mount Lemmon Observatory by astronomers Theodore Pruyne and Kacper Wierzchoś on 15 February 2020, as part of the Mount Lemmon Survey or Catalina Sky Survey. The asteroid's discovery was announced by the Minor Planet Center on 25 February 2020, after subsequent observations confirmed that it was orbiting Earth.
