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RHESSI
Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI, originally High Energy Solar Spectroscopic Imager or HESSI or Explorer 81) was a NASA solar flare observatory. It was the sixth mission in the Small Explorer program (SMEX), selected in October 1997 and launched on 5 February 2002, at 20:58:12 UTC. Its primary mission was to explore the physics of particle acceleration and energy release in solar flares. Spacecraft HESSI was renamed to RHESSI on 29 March 2002 in honor of Dr. Ramaty, a pioneer in the area of high energy solar physics. RHESSI was the first space mission named after a NASA scientist. RHESSI was built by Spectrum Astro for Goddard Space Flight Center and was operated by the Space Sciences Laboratory in Berkeley, California. The principal investigator from 2002 to 2012 was Robert Lin, who was succeeded by Säm Krucker. The entire spacecraft rotated to provide the necessary signal modulation. The four, fixed solar panels were designed to provide enou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reuven Ramaty
Dr. Reuven Ramaty (1937—2001) was a Hungarian astrophysicist who worked for 30 years at NASA's NASA Goddard Space Flight Centre. He was a leader in the fields of solar physics, gamma-ray line spectrometry, nuclear astrophysics, and low-energy cosmic rays. Ramaty was a founding member of NASA's High Energy Solar Spectroscopic Imager which has now been renamed the Reuven Ramaty High Energy Solar Spectroscopic Imager in his honour. This was the first space mission to be named after a NASA scientist and was operational from 2002 until 2018. The Online Archive of California holds over 400 entries for documents, papers and photographs published by and of Ramaty and his work. Ramaty made many contributions in the field of astrophysics and solar physics. He was given the Goddard Lindsay Awarin 1980 and had a tribute dedicated to his work at the University of Maryland in 2000. Early life Ramaty was born on February 25, 1937, to two Hungarian parents Michael Miki Reiter and Eliz Ramaty, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explorer Program
The Explorers program is a NASA exploration program that provides flight opportunities for physics, geophysics, heliophysics, and astrophysics investigations from space. Launched in 1958, Explorer 1 was the first spacecraft of the United States to achieve orbit. Over 90 space missions have been launched since. Starting with Explorer 6, it has been operated by NASA, with regular collaboration with a variety of other institutions, including many international partners. Launchers for the Explorer program have included Juno I, Juno II, various Thor, Scout, Delta and Pegasus launch vehicles, and Falcon 9. The program has three classes: Medium-Class Explorers (MIDEX), Small Explorers (SMEX), and University-Class Explorers (UNEX), with select Missions of Opportunity operated with other agencies. History Early Explorer satellites The Explorer program began as a U.S. Army proposal (Project Orbiter) to place a "civilian" artificial satellite into orbit during the International ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Sciences Laboratory
The Space Sciences Laboratory (SSL) is an Organized Research Unit (ORU) of the University of California, Berkeley. Founded in 1959, the laboratory is located in the Berkeley Hills above the university campus. It has developed and continues to develop many projects in the space sciences, including the search for extraterrestrial life ( SETI@home). History The Space Sciences Laboratory (SSL) at Berkeley, California was initiated in 1958 by a committee of faculty members who recognized that emerging rocket and satellite technology opened up new investigative realms for the physical, biological, and engineering sciences. The committee, chaired first by Professor Otto Struve of the Department of Astronomy and subsequently by Professor Edward Teller of the Department of Physics and the Lawrence Radiation Laboratory, explored with faculty members the opportunities associated with space research as well as the impact of rapidly escalating national space exploration programs ( i.e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilkinson Microwave Anisotropy Probe
The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe (MAP and Explorer 80), was a NASA spacecraft operating from 2001 to 2010 which measured temperature differences across the sky in the cosmic microwave background (CMB) – the radiant heat remaining from the Big Bang. Headed by Professor Charles L. Bennett of Johns Hopkins University, the mission was developed in a joint partnership between the NASA Goddard Space Flight Center and Princeton University. The WMAP spacecraft was launched on 30 June 2001 from Florida. The WMAP mission succeeded the COBE space mission and was the second medium-class (MIDEX) spacecraft in the NASA Explorer program. In 2003, MAP was renamed WMAP in honor of cosmologist David Todd Wilkinson (1935–2002), who had been a member of the mission's science team. After nine years of operations, WMAP was switched off in 2010, following the launch of the more advanced Planck spacecraft by European Space Agency ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coded Aperture
Coded apertures or coded-aperture masks are grids, gratings, or other patterns of materials opaque to various wavelengths of electromagnetic radiation. The wavelengths are usually high-energy radiation such as X-rays and gamma rays. By blocking radiation in a known pattern, a coded "shadow" is cast upon a plane. The properties of the original radiation sources can then be mathematically reconstructed from this shadow. Coded apertures are used in X- and gamma ray imaging systems, because these high-energy rays cannot be focused with lenses or mirrors that work for visible light. Rationale Imaging is usually done at optical wavelengths using lenses and mirrors. However, the energy of hard X-rays and γ-rays is too high to be reflected or refracted, and simply passes through the lenses and mirrors of optical telescopes. Image modulation by apertures is therefore often used instead. The pinhole camera is the most basic form of such a modulation imager, but its disadvantage is low th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CHIPS (satellite)
CHIPS (Cosmic Hot Interstellar Plasma Spectrometer, also Explorer 82 or UNEX-2) was a NASA Explorer program satellite. It was launched on 12 January 2003 from Vandenberg Air Force Base aboard a Delta II with the larger satellite ICESat, and had an intended mission duration of one year. CHIPS was the second of NASA's University Explorer (UNEX) mission class. It performed spectroscopy from 90 to 250 Angstrom (9 to 26-nm) extreme ultraviolet (EUV) light. Mission The primary objective of the science team, led by principal investigator Mark Hurwitz, was to study the million-degree gas in the local interstellar medium. CHIPS was designed to capture the first spectra of the faint, extreme ultraviolet glow that is expected to be emitted by the hot interstellar gas within about 300 light-years of the Sun, a region often referred to as the Local Bubble. Surprisingly, these measurements produced a null result, with only very faint EUV emissions detected, despite theoretical expectations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pegasus (rocket)
Pegasus is an air-launched launch vehicle developed by Orbital Sciences Corporation (OSC) and now built and launched by Northrop Grumman. Capable of carrying small payloads of up to into low Earth orbit, Pegasus first flew in 1990 and remains active . The vehicle consists of three solid propellant stages and an optional monopropellant fourth stage. Pegasus is released from its carrier aircraft at approximately , and its first stage has a wing and a tail to provide lift and attitude control while in the atmosphere. Notably, the first stage does not have a thrust vector control (TVC) system. History Pegasus was designed by a team led by Antonio Elias. The Pegasus's three Orion solid motors were developed by Hercules Aerospace (later Alliant Techsystems) specifically for the Pegasus launcher but using advanced carbon fiber, propellant formulation and case insulation technologies originally developed for the terminated USAF Small ICBM program. The wing and fins' structures w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Sciences Corporation
Orbital Sciences Corporation (commonly referred to as Orbital) was an American company specializing in the design, manufacture, and launch of small- and medium- class space and launch vehicle systems for commercial, military and other government customers. In 2014, Orbital merged with Alliant Techsystems to create a new company called Orbital ATK, Inc., which in turn was purchased by Northrop Grumman in 2018. The remnants of the former Orbital Sciences Corporation today are a subsidiary of Northrop Grumman, known as Northrop Grumman Innovation Systems. Orbital was headquartered in Dulles, Virginia and publicly traded on the New York Stock Exchange with the ticker symbol ORB. Orbital's primary products were satellites and launch vehicles, including low Earth orbit (LEO), geosynchronous Earth orbit and planetary spacecraft for communications, remote sensing, scientific and defense missions; ground- and air-launched launch vehicles that delivered satellites into orbit; missile d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germanium
Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors silicon and tin. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature. Because it seldom appears in high concentration, germanium was discovered comparatively late in the discovery of the elements. Germanium ranks near fiftieth in relative abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev predicted its existence and some of its properties from its position on his periodic table, and called the element ekasilicon. In 1886, Clemens Winkler at Freiberg University found the new element, along with silver and sulfur, in the mineral argyrodite. Winkler named the element after his country, Germany. Germanium is mined primarily from sphalerite (the primary ore of zinc), though germanium is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attitude Control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle attitude requires sensors to measure vehicle orientation, actuators to apply the torques needed to orient the vehicle to a desired attitude, and algorithms to command the actuators based on (1) sensor measurements of the current attitude and (2) specification of a desired attitude. The integrated field that studies the combination of sensors, actuators and algorithms is called guidance, navigation and control (GNC). Aircraft attitude control An aircraft's attitude is stabilized in three directions: ''Yaw (rotation), yaw'', nose left or right about an axis running up and down; ''pitch'', nose up or down about an axis running from wing to wing; and ''roll'', rotation about an axis running from nose to tail. Elevator (aeronautics), Elevat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectric Effect
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid state and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission. The experimental results disagree with classical electromagnetism, which predicts that continuous light waves transfer energy to electrons, which would then be emitted when they accumulate enough energy. An alteration in the intensity of light would theoretically change the kinetic energy of the emitted electrons, with sufficiently dim light resulting in a delayed emission. The experimental results instead show that electrons are dislodged only when the light exceeds a certain frequency—regardless of the light's intensity or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Panels On Spacecraft
Spacecraft operating in the inner Solar System usually rely on the use of power electronics-managed photovoltaic solar panels to derive electricity from sunlight. Outside the orbit of Jupiter, solar radiation is too weak to produce sufficient power within current solar technology and spacecraft mass limitations, so radioisotope thermoelectric generators (RTGs) are instead used as a power source.NASA JPL Publication: Basics of Space Flight, Chapter 11. Typical Onboard Systems, Electrical Power Supply and Distribution Subsystems, History The first practical silicon-based solar cells were introduced by Bell Labs in April 1954. They were initially about 6% efficient, but improvements began to raise this number almost immediately. Bell had been interested in the idea as a system to provide power at remote telephone repeater stations, but the cost of the devices was far too high to be practical in this role. Aside from small experimental kits and uses, the cells remained largely unus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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