Galileo is prepared for mating with the IUS booster

Galileo and Inertial Upper Stage being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission

Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. Named after the astronomer and Renaissance pioneer Galileo Galilei, it was launched on October 18, 1989 by the Space Shuttle Atlantis on the STS-34 mission. It arrived at Jupiter on December 7, 1995, a little more than six years later, via gravitational assist flybys of Venus and Earth. Image File history File links Galileo_mission_patch. ... Download high resolution version (1200x1500, 1988 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1200x1500, 1988 KB) Wikipedia does not have an article with this exact name. ... The Galileo spacecraft and its attached Inertial Upper Stage (IUS) booster being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission The Inertial Upper Stage or IUS is a two-stage solid-fueled booster rocket developed by NASA and the U.S. Air Force for... Galileo probe deplyed (large). ... Galileo probe deplyed (large). ... Space Shuttle Orbiter Atlantis (NASA Orbiter Vehicle Designation: OV-104) is one of the fleet of space shuttles belonging to the U.S. National Aeronautics and Space Administration (NASA). ... STS-34 was a space shuttle mission by NASA using the Space Shuttle Atlantis. ... Unmanned space missions are those using remote-controlled spacecraft. ... The National Aeronautics and Space Administration (NASA) is an agency of the United States federal government, responsible for the nations public space program. ... The eight planets and three dwarf planets of the Solar System. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... An astronomer or astrophysicist is a person whose area of interest is astronomy or astrophysics. ... The Renaissance (French for rebirth, or Rinascimento in Italian), was a cultural movement in Italy (and in Europe in general) that began in the late Middle Ages, and spanned roughly the 14th through the 17th century. ... KDFSAJFKASJDKFJASDKLJFDKLASJFLKJASKLFJLAKSJFLKSJALFKJSKLJFto the Sun-centered solar system which Galileo supported. ... October 18 is the 291st day of the year (292nd in leap years). ... 1989 (MCMLXXXIX) was a common year starting on Sunday of the Gregorian calendar. ... Space Shuttle Orbiter Atlantis (NASA Orbiter Vehicle Designation: OV-104) is one of the fleet of space shuttles belonging to the U.S. National Aeronautics and Space Administration (NASA). ... STS-34 was a space shuttle mission by NASA using the Space Shuttle Atlantis. ... December 7 is the 341st day (342nd in leap years) of the year in the Gregorian calendar. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ... (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ...

Galileo conducted the first asteroid flyby, discovered the first asteroid moon, was the first spacecraft to orbit Jupiter, and launched the first probe into Jupiter's atmosphere. It has been suggested that minor planet be merged into this article or section. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ...

On September 21, 2003, after 14 years in space and 8 years of service in the Jovian system, Galileo's mission was terminated by sending the orbiter into Jupiter's atmosphere at a speed of nearly 50 kilometres per second to avoid any chance of it contaminating local moons with bacteria from Earth. Of particular concern was the ice-crusted moon Europa, which, thanks to Galileo, scientists now suspect harbors a salt water ocean beneath its surface. September 21 is the 264th day of the year (265th in leap years). ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... Apparent magnitude: 5. ... Animated map exhibiting the worlds oceanic waters. ...

Mission overview

Galileo's launch had been significantly delayed by the hiatus in Space Shuttle launches that occurred after the Challenger space shuttle disaster. New safety protocols introduced as a result of the Challenger accident forced Galileo to use a lower-powered upper stage booster rocket, instead of a Centaur booster rocket, to send it from Earth orbit to Jupiter; several gravitational slingshots (once by Venus and twice by Earth), called a "VEEGA" or Venus Earth Earth Gravity Assist maneuver, provided the additional velocity required to reach its destination. Along the way Galileo performed close observation of the asteroids 951 Gaspra (October 29, 1991) and 243 Ida, and discovered Ida's moon Dactyl. In 1994 Galileo was perfectly positioned to watch the fragments of comet Shoemaker-Levy 9 crash into Jupiter. Terrestrial telescopes had to wait to see the impact sites as they rotated into view. NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... Space Shuttle Challenger (NASA Orbiter Vehicle Designation: OV-099) was NASAs second Space Shuttle orbiter to be put into service. ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... Model of Centaur with Surveyor as payload. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... m. ... It has been suggested that sling effect be merged into this article or section. ... (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... 951 Gaspra is an S-type asteroid that orbits very close to the inner edge of the asteroid belt. ... October 29 is the 302nd day of the year (303rd in leap years) in the Gregorian calendar. ... 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ... NASA image of 243 Ida. ... 243 Ida (left) and Dacytl (right), as photographed by Galileo. ... Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. ...

Galileo's prime mission was a two-year study of the Jovian system. The spacecraft traveled around Jupiter in elongated ellipses, each orbit lasting about two months. The differing distances from Jupiter afforded by these orbits allowed Galileo to sample different parts of the planet's extensive magnetosphere. The orbits were designed for close up flybys of Jupiter's largest moons. Once Galileo's prime mission was concluded, an extended mission followed starting on December 7, 1997; the spacecraft made a number of daring close flybys of Jupiter's moons Europa and Io. The closest approach was 180 km (112 mi) on October 15, 2001. The radiation environment near Io in particular was very unhealthy for Galileo's systems, and so these flybys were saved for the extended mission when loss of the spacecraft would be more acceptable. For other uses, see Ellipse (disambiguation). ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ... December 7 is the 341st day (342nd in leap years) of the year in the Gregorian calendar. ... 1997 (MCMXCVII) was a common year starting on Wednesday of the Gregorian calendar. ... Apparent magnitude: 5. ... Atmospheric characteristics Atmospheric pressure trace Sulfur dioxide 90% Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter. ... October 15 is the 288th day of the year (289th in leap years). ... 2001 (MMI) was a common year starting on Monday of the Gregorian calendar. ... Radiation as used in physics, is energy in the form of waves or particles. ...

Galileo's cameras were deactivated on January 17, 2002 after they had sustained irrecoverable radiation damage. NASA engineers were able to recover the damaged tape recorder electronics, and once more Galileo continued to return other scientific data until it was deorbited in 2003 as described above, performing one last scientific experiment —a measurement of Amalthea's mass as Galileo swung by. January 17 is the 17th day of the year in the Gregorian calendar. ... For album titles with the same name, see 2002 (album). ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Amalthea (am-É™l-thee-É™, IPA: , Greek Αμάλθεια) is the third moon of Jupiter in order of distance from the planet, and the fifth in order of discovery. ...

The Galileo spacecraft

Overview of Galileo's components

The Jet Propulsion Laboratory built the Galileo spacecraft and managed the Galileo mission for NASA. Germany supplied the propulsion module. NASA's Ames Research Center managed the probe, which was built by Hughes Aircraft Company. Download high resolution version (1041x720, 251 KB)Galileo spacecraft, simpler diagram. ... Download high resolution version (1041x720, 251 KB)Galileo spacecraft, simpler diagram. ... The NASA Jet Propulsion Laboratory (JPL), in Pasadena and La Cañada Flintridge, near Los Angeles, California, USA, builds and operates unmanned spacecraft for the National Aeronautics and Space Administration (NASA). ... Aerial View of Moffett Field and NASA Ames Research Center. ... Hughes developed the AIM-120 AMRAAM, one of the worlds most advanced air-to-air missiles Hughes Aircraft Company was a major defence/aerospace company founded by Howard Hughes. ...

At launch, the orbiter and probe together had a mass of 2,564 kilograms (5,653 pounds) and was seven metres tall. One section of the spacecraft rotated at 3 rpm, keeping Galileo stable and holding six instruments that gathered data from many different directions, including the fields and particles instruments. The other section of the spacecraft was an antenna and data were periodically transmitted to it, back on the ground the mission operations team used software containing 650,000 lines of programming code in the orbit sequence design process; 1,615,000 lines in the telemetry interpretation; and 550,000 lines of code in navigation. The U.S. National Prototype Kilogram, which currently serves as the primary standard for measuring mass in the U.S. It was assigned to the United States in 1889 and is periodically recertified and traceable to the primary international standard, The Kilogram, held at the Bureau International des Poids et... The pound (abbreviations: lb or, sometimes in the United States, #) is a unit of mass in a number of different systems, including various systems of units of mass that formed part of English units, Imperial units, and United States customary units. ... The or meter (see spelling differences) is a measure of length. ... Revolutions per minute (abbreviated rpm, RPM, r/min, or min-1) is a unit of frequency, commonly used to measure rotational speed, in particular in the case of rotation around a fixed axis. ...

The spacecraft was controlled by a RCA 1802 Cosmac microprocessor CPU, clocked at about 1.6 MHz, and fabricated on sapphire (Silicon on Sapphire) which is a radiation-and static-hardened material ideal for spacecraft operation. This microprocessor was the first low-power CMOS processor chip, quite on a par with the 8-bit 6502 that was being built into the Apple II desktop computer at that time. Galileo's attitude control system software was written in the HAL/S programming language, also used in the Space Shuttle program. The 1802 CPU had previously been used onboard the Voyager and Viking spacecraft. The RCA (CDP)1802 (aka RCA COSMAC*, COSMAC 1802) is an 8-bit CMOS microprocessor (µP) introduced by RCA in early 1976, and presently being manufactured by Intersil Corporation. ... A microprocessor is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semiconducting integrated circuit (IC). ... Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... Sapphire (from Hebrew: ספיר Sapir) is the single-crystal form of aluminium oxide (Al2O3), a mineral known as corundum. ... Silicon on sapphire (SOS) is a hetero-epitaxial process for integrated circuit manufacturing that consists of a thin layer (typically thinner than 0. ... Static CMOS Inverter Complementary metal–oxide–semiconductor (CMOS) (see-moss, IPA: ), is a major class of integrated circuits. ... The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. ... The Apple II was one of the most popular personal computers of the 1980s. ... HAL/S is a real-time aerospace programming language, best known for its use in the Space Shuttle program. ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... Voyager Project redirects here. ... Viking mission profile. ...

Propulsion

The Propulsion Subsystem consisted of a 400 N main engine and twelve 10 N thrusters together with propellant, storage and pressurizing tanks, and associated plumbing. The fuel for the system was 925 kg of monomethyl hydrazine and nitrogen tetroxide. Two separate tanks held another 7 kg of helium pressurant. The Propulsion Subsystem was developed and built by Daimler Benz Aero Space AG (DASA) (formerly Messerschmitt–Bölkow–Blohm (MBB)) and provided by Germany, the major international partner in Project Galileo.^[1] The newton (symbol: N) is the SI unit of force. ... Hydrazine is the chemical compound with formula N2H4. ... Nitrogen tetroxide (or Dinitrogen tetroxide) (N2O4) is a hypergolic propellant often used in combination with a hydrazine-based rocket fuel. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... Luftwaffe Tornado ECR Deutsche Aerospace AG Daimler-Benz Aerospace AG DaimlerChrysler Aerospace AG Founded May 19, 1989 as Deutsche Aerospace AG, bundling space and aeronautic elements of Daimler-Benz (including Dornier Luftfahrt), Messerschmitt-Bölkow-Blohm (MBB), MTU München, and Telefunken Systemtechnik (TST) In 1992, the helicopter division was... Messerschmitt is a famous German aircraft manufacturer, known primarily for their World War II fighter aircraft, notably the Bf 109 and Me 262. ...

Galileo's power

Solar panels were not a practical solution for Galileo's power needs at Jupiter's distance from the Sun (it would have needed a minimum of 65 square metres (700 ft²) of solar panels); as for batteries, they would have been prohibitively massive. The solution adopted consisted of two radioisotope thermoelectric generators (RTGs). The RTGs powered the spacecraft through the radioactive decay of plutonium-238. The heat emitted by this decay was converted into electricity for the spacecraft through the solid-state Seebeck effect. This provided a reliable and long-lasting source of electricity unaffected by the cold space environment and high radiation fields such as those encountered in Jupiter's magnetosphere. Solar Panel made by BP Solar The solar panels (photovoltaic arrays) on this small yacht at sea can charge the 12 V batteries at up to 9 Amps in full, direct sunlight. ... // A radioisotope thermoelectric generator (RTG) is a simple electrical generator which obtains its power from radioactive decay. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight (244) g·mol−1 Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... The Peltier-Seebeck effect, or thermoelectric effect, is the direct conversion of heat differentials to electric voltage and vice versa. ...

Each RTG, mounted on a 5-meter long boom, carried 7.8 kilograms (17.2 lb) of ²³⁸Pu.^[2] Each RTG contained 18 separate heat source modules, and each module encased four pellets of plutonium dioxide, a ceramic material resistant to fracturing. The modules were designed to survive a range of hypothetical accidents: launch vehicle explosion or fire, re-entry into the atmosphere followed by land or water impact, and post-impact situations. An outer covering of graphite provided protection against the structural, thermal, and eroding environments of a potential re-entry. Additional graphite components provided impact protection, while iridium cladding of the fuel cells provided post-impact containment. The RTGs produced about 570 watts at launch. The power output initially decreased at the rate of 0.6 watts per month and was 493 watts when Galileo arrived at Jupiter. Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... Graphite (named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): to draw/write, for its use in pencils) is one of the allotropes of carbon. ... General Name, Symbol, Number iridium, Ir, 77 Chemical series transition metals Group, Period, Block 9, 6, d Appearance silvery white Atomic mass 192. ...

As the launch of Galileo neared, anti-nuclear groups, concerned over what they perceived as an unacceptable risk to the public's safety from Galileo's RTGs, sought a court injunction prohibiting Galileo's launch. RTGs had been used for years in planetary exploration without mishap: the Lincoln Experimental Satellites 8/9, launched by the U.S. Department of Defense, had 7% more plutonium on board than Galileo, and the two Voyager spacecraft each carried 80% as much plutonium as Galileo did. However, activists remembered the messy crash of the Soviet Union's nuclear-powered Cosmos 954 satellite in Canada in 1978, and the 1986 Challenger accident had raised public awareness of the possibility of explosive spacecraft failures. Also, no RTGs had ever been made to swing past the Earth at close range and high speed, as Galileo's Venus-Earth-Earth Gravity Assist trajectory required it to do. This created a novel mission failure modality that might plausibly have entailed total dispersal of Galileo's plutonium in the Earth's atmosphere. Scientist Carl Sagan, for example, a strong supporter of the Galileo mission, said in 1989 that "there is nothing absurd about either side of this argument." ^[3] The United States Department of Defense, abbreviated DoD or DOD and sometimes called the Defense Department, is a civilian Cabinet organization of the United States government. ... The Voyager spacecraft Launch of Voyager 2 Voyager is also the name of a planned series of unmanned probes to Mars, cancelled in 1968. ... Cosmos 954 was a Soviet Radar Ocean Reconnaissance Satellite (RORSAT) with an onboard nuclear reactor. ... STS-51-L was the 25th launch of a Space Shuttle and the tenth launch of the Challenger. ...

After the Challenger accident, a study considered additional shielding and eventually rejected it, in part because such a design significantly increased the overall risk of mission failure and only shifted the other risks around (for example, if a failure on orbit had occurred, additional shielding would have significantly increased the consequences of a ground impact).^[2]

Instrumentation overview

Scientific instruments to measure fields and particles were mounted on the spinning section of the spacecraft, together with the main antenna, power supply, the propulsion module and most of the galileo computers and control electronics. The sixteen instruments, weighing 118 kg altogether, included magnetometer sensors mounted on an 11 m boom to minimize interference from the spacecraft; a plasma instrument for detecting low energy charged particles and a plasma wave detector to study waves generated by the particles; a high energy particle detector; and a detector of cosmic and Jovian dust. It also carried the Heavy Ion Counter, an engineering experiment added to assess the potentially hazardous charged particle environments the spacecraft flew through, and an added Extreme Ultraviolet detector associated with the UV spectrometer on the scan platform. A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves. ... A magnetometer is a scientific instrument used to measure the strength and/or direction of the magnetic field in the vicinity of the instrument. ... A Plasma lamp In physics and chemistry, a plasma is an ionized gas, and is usually considered to be a distinct phase of matter. ... After just three years of use, dust has blocked this laptop heat sink, making the computer unusable Dust is a general name for minute solid particles with diameters less than 500 micrometers (otherwise, please see sand or granulates and, more generally, finely divided matter). ... UV redirects here. ...

The despun section's instruments included the camera system; the near infrared mapping spectrometer to make multi-spectral images for atmospheric and moon surface chemical analysis; ultraviolet spectrometer to study gases; and photo-polarimeter radiometer to measure radiant and reflected energy. The camera system was designed to obtain images of Jupiter's satellites at resolutions from 20 to 1,000 times better than Voyager's best, because Galileo flew closer to the planet and its inner moons and because the CCD sensor in Galileo's camera was more sensitive and had a broader color detection band than the vidicons of Voyager. Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... Voyager Project redirects here. ... A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... In older video cameras, prior to the 1990s, a video camera tube or pickup tube was used instead of a charge-coupled device (CCD). ...

Instrumentation details

The following information was taken directly from NASA's Galileo legacy site.^[4]

Despun section

Highly detailed diagram of Galileo instruments and subsystems.

Image File history File links Download high-resolution version (1442x1053, 63 KB) Highly detailed diagram of Galileo spacecraft instrumentation and subsystems source: http://www2. ... Image File history File links Download high-resolution version (1442x1053, 63 KB) Highly detailed diagram of Galileo spacecraft instrumentation and subsystems source: http://www2. ...

Solid State Imager (SSI)

The SSI is an 800 by 800 pixel solid state camera consisting of an array of silicon sensors called a "charge coupled device" (CCD). The optical portion of the camera is built as a Cassegrain telescope. Light is collected by the primary mirror and directed to a smaller secondary mirror that channels it through a hole in the center of the primary mirror and onto the CCD. The CCD sensor is shielded from radiation, a particular problem within the harsh Jovian magnetosphere. The shielding is accomplished by means of a 10 mm thick layer of tantalum surrounding the CCD except where the light enters the system. An eight position filter wheel is used to obtain images at specific wavelengths. The images are then combined electronically on Earth to produce color images. The spectral response of the SSI ranges from about 0.4 to 1.1 micrometres. The SSI weighs 29.7 kilograms and consumes, on average, 15 watts of power.^[5][6] A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... Light path in a Cassegrain reflector Laurent Cassegrain was a catholic priest born in the region of Chartres around 1629 and died at Chaudon (Eure-et-Loir) on August 31, 1693. ... Radiation as used in physics, is energy in the form of waves or particles. ... General Name, Symbol, Number tantalum, Ta, 73 Chemical series transition metals Group, Period, Block 5, 6, d Appearance gray blue Atomic mass 180. ...

Near-Infrared Mapping Spectrometer (NIMS)

The NIMS instrument is sensitive from 0.7 to 5.2 micrometre wavelength IR light, overlapping the wavelength range of SSI. The telescope associated with NIMS is all reflective (uses mirrors and no lenses) with an aperture of 229 mm. The spectrometer of NIMS uses a grating to disperse the light collected by the telescope. The dispersed spectrum of light is focused on detectors of indium antimonide and silicon. The NIMS weighs 18 kilograms and uses 12 watts of power on average.^[7][8] A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... Look up ir in Wiktionary, the free dictionary. ... General Name, Symbol, Number indium, In, 49 Chemical series poor metals Group, Period, Block 13, 5, p Appearance silvery lustrous gray Atomic mass 114. ... Antimonides are compounds of antimony with more electropositive elements. ... It has been suggested that Silicons ranking be merged into this article or section. ...

Ultraviolet Spectrometer / Extreme Ultraviolet Spectrometer (UVS/EUV)

The Cassegrain telescope of the UVS has a 250 mm aperture and collects light from the observation target. Both the UVS and EUV instruments use a ruled grating to disperse this light for spectral analysis. This light then passes through an exit slit into photomultiplier tubes that produce pulses or "sprays" of electrons. These electron pulses are counted, and these count numbers are the data that are sent to Earth. The UVS is mounted on the scan platform and can be pointed to an object in inertial space. The EUV is mounted on the spun section of the spacecraft. As Galileo spins, the EUV observes a narrow ribbon of space perpendicular to the spin axis. The two instruments combined weigh about 9.7 kilograms and use 5.9 watts of power.^[9][10] Light path in a Cassegrain reflector Laurent Cassegrain was a catholic priest born in the region of Chartres around 1629 and died at Chaudon (Eure-et-Loir) on August 31, 1693. ... In optics, a diffraction grating is an array of fine, parallel, equally spaced grooves (rulings) on a reflecting or transparent substrate. ... Photomultipliers, or photomultiplier tubes (PMT) are extremely sensitive detectors of light in the ultraviolet, visible and near infrared. ...

Photopolarimeter-Radiometer (PPR)

The PPR has seven radiometry bands. One of these uses no filters and observes all the radiation, both solar and thermal. Another band lets only solar radiation through. The difference between the solar- plus-thermal and the solar-only channels gives the total thermal radiation emitted. The PPR also measured in five broadband channels that span the spectral range from 17 to 110 micrometres. The radiometer provides data on the temperatures of the Jovian satellites and Jupiter's atmosphere. The design of the instrument is based on that of an instrument flown on the Pioneer Venus spacecraft. A 100 mm aperture reflecting telescope collects light, directs it to a series of filters, and, from there, measurements are performed by the detectors of the PPR. The PPR weighs 5.0 kilograms and consumes about 5 watts of power.^[11][12]

Spun section

Dust Detector Subsystem (DDS)

The Dust Detector Subsystem (DDS) was used to measure the mass, electric charge, and velocity of incoming particles. The masses of dust particles that the DDS can detect go from 10⁻¹⁶ to 10⁻⁷ grams. The speed of these small particles can be measured over the range of 1 to 70 kilometers per second. The instrument can measure impact rates from 1 particle per 115 days (10 megaseconds) to 100 particles per second. These particles will help determine dust origin and dynamics within the magnetosphere. The DDS weighs 4.2 kilograms and uses an average of 5.4 watts of power.^[13][14] A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ...

Energetic Particles Detector (EPD)

The energetic particles detector (EPD) is designed to measure the numbers and energies of ions and electrons whose energies exceed about 20 keV (3.2 fJ). The EPD can also measure the direction of travel of such particles and, in the case of ions, can determine their composition (whether the ion is oxygen or sulfur, for example). The EPD uses silicon solid state detectors and a time-of-flight detector system to measure changes in the energetic particle population at Jupiter as a function of position and time. These measurements will tell us how the particles get their energy and how they are transported through Jupiter's magnetosphere. The EPD weighs 10.5 kilograms and uses 10.1 watts of power on average.^[15][16] Kev can refer to either: A regional term for the chav social group in the United Kingdom An abbreviation - keV - of the unit Kiloelectronvolt An abbreviation for the given name Kevin. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Standard atomic weight 32. ... The Time of flight method of measuring particle mass is done as follows. ...

Heavy Ion Counter (HIC)

The HIC is really a repackaged and updated version of some parts of the flight spare of the Voyager Cosmic Ray System. The HIC detects heavy ions using stacks of single crystal silicon wafers. The HIC can measure heavy ions with energies as low as 6 MeV (1 pJ) and as high as 200 MeV (32 pJ) per nucleon. This range includes all atomic substances between carbon and nickel. The HIC and the EUV share a communications link and, therefore, must share observing time. The HIC weighs 8 kilograms and uses an average of 2.8 watts of power.^[17][18] Voyager Project redirects here. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic and silvery with a gold tinge Standard atomic weight 58. ...

Magnetometer (MAG)

The magnetometer (MAG) uses two sets of three sensors. The three sensors allow the three orthogonal components of the magnetic field section to be measured. One set is located at the end of the magnetometer boom and, in this position, is about 11 m from the spin axis of the spacecraft. The second set, designed to detect stronger fields, is 6.7 m from the spin axis. The boom is used to remove the MAG from the immediate vicinity of the spacecraft to minimize magnetic effects from the spacecraft. However, not all these effects can be eliminated by distancing the instrument. The rotation of the spacecraft is used to separate natural magnetic fields from engineering induced fields. Another source of potential error in measurement comes from bending and twisting of the long magnetometer boom. To account for these motions, a calibration coil is mounted rigidly on the spacecraft and puts out a reference magnetic field during calibrations. The magnetic field at the surface of the Earth has a strength of about 50,000 nT. At Jupiter, the outboard (11 m) set of sensors can measure magnetic field strengths in the range from ±32 to ±512 nT while the inboard (6.7 m) set is active in the range from ±512 to ±16,384 nT. The MAG experiment weighs 7 kilograms and uses 3.9 watts of power.^[19][20] A magnetometer is a scientific instrument used to measure the strength and/or direction of the magnetic field in the vicinity of the instrument. ... In physics, a magnetic field is a force field that surrounds electric current circuits. ... The nanotesla (nT) is a unit of magnetic flux density equal to 10−9 tesla (unit). ...

Plasma Subsystem (PLS)

The PLS uses seven fields of view to collect charged particles for energy and mass analysis. These fields of view cover most angles from 0 to 180 degrees, fanning out from the spin axis. The rotation of the spacecraft carries each field of view through a full circle. The PLS will measure particles in the energy range from 0.9 eV to 52 keV (0.1 aJ to 8.3 fJ). The PLS weighs 13.2 kilograms and uses an average of 10.7 watts of power.^[21][22] Particle radiation is the radiation of energy by means of small fast-moving particles that have energy and mass. ...

Plasma Wave Subsystem (PWS)

An electric dipole antenna is used to study the electric fields of plasmas, while two search coil magnetic antennas studied the magnetic fields. The electric dipole antenna is mounted at the tip of the magnetometer boom. The search coil magnetic antennas are mounted on the high-gain antenna feed. Nearly simultaneous measurements of the electric and magnetic field spectrum allowed electrostatic waves to be distinguished from electromagnetic waves. The PWS weighs 7.1 kilograms and uses an average of 9.8 watts.^[23][24] A simple half-wave dipole antenna that a shortwave listener might build. ... A Plasma lamp In physics and chemistry, a plasma is an ionized gas, and is usually considered to be a distinct phase of matter. ...

Galileo's atmospheric entry probe

Timeline of Galileo atmospheric entry probe. (The Probe transmitted data to the Orbiter continuously for 57.6 minutes reaching a depth of 23 bars (2.3 MPa) but the relay link to the Orbiter began at four minutes after entry, so transmission ended 61.4 minutes after entry.)

Diagram of Galileo atmospheric entry probe instruments and subsystems.

The 339 kilogram atmospheric probe, built by Hughes Aircraft Company at its El Segundo, California plant, measured about 1.3 meters across. Inside the heat shield, the scientific instruments were protected from ferocious heat during entry. The probe had to withstand extreme heat and pressure on its high speed journey at 47.8 km/s. The probe was released from the main spacecraft in July 1995, five months before reaching Jupiter, and entered Jupiter's atmosphere with no braking beforehand. It was slowed from the probe's arrival speed of about 47 kilometers per second to subsonic speed in less than 2 minutes. This was by far the most difficult atmospheric entry ever attempted; the probe's 152 kg heat shield made up almost half of the probe's total mass, and lost 80 kg during the entry. ^{[25] [26]} NASA built a special laboratory, the Giant Planet Facility to simulate the heat load, which was similar to that of an ICBM-style straight-down reentry through a thermonuclear fireball.^{[27] [28]} It then deployed its 2.5-meter (8-foot) parachute, and dropped its heat shield. Download high resolution version (1800x1364, 326 KB)Galileo atmospheric probe entry. ... Download high resolution version (1800x1364, 326 KB)Galileo atmospheric probe entry. ... Download high resolution version (1534x1513, 206 KB)Galileo atmospheric entry probe diagram File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Download high resolution version (1534x1513, 206 KB)Galileo atmospheric entry probe diagram File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Hughes logo adopted after his death Hughes developed the AIM-120 AMRAAM, one of the worlds most advanced air-to-air missiles Hughes Aircraft Company was a major defense/aerospace company founded by Howard Hughes. ... The El Segundo skyline, as seen from Sepulveda Boulevard (CA/SR-1) El Segundo is a city in Los Angeles County, California on the Santa Monica Bay, incorporated on January 18, 1917. ... In aeronautics, a heat shield is a protective layer on a spacecraft or ballistic missile that is designed to protect it from high temperatures, usually those that result from aerobraking during entry into a planets atmosphere. ... Atmospheric entry is the transition from the vacuum of space to the atmosphere of any planet or other celestial body. ... This article refers to the device for slowing descent through the air. ...

As the probe descended through 150 kilometers of the top layers of the atmosphere, it collected 58 minutes of data on the local weather and only stopped transmitting when ambient pressure exceeded 23 atmospheres. The data were sent to the spacecraft overhead, then transmitted back to Earth. Each of 2 L-band transmitters operated at 128 bits per second and sent nearly identical streams of scientific data to the orbiter. All the probe's electronics were powered by lithium sulfur dioxide (LiSO₂) batteries that provided a nominal power output of about 580 watts with an estimated capacity of about 21 ampere-hours on arrival at Jupiter. The probe included six instruments for taking data on its plunge into Jupiter: Weather is a term that encompasses phenomena in the atmosphere of a planet. ... Standard atmosphere (symbol: atm) is a unit of pressure. ... CR2032 lithium battery Lithium batteries are primary batteries that have lithium metal anodes. ...

• an atmospheric structure instrument group measuring temperature, pressure and deceleration,
• a neutral mass spectrometer and
• a helium-abundance interferometer supporting atmospheric composition studies,
• a nephelometer for cloud location and cloud-particle observations,
• a net-flux radiometer measuring the difference between upward and downward radiant flux at each altitude, and
• a lightning/radio-emission instrument with an energetic-particle detector that measured light and radio emissions associated with lightning and energetic particles in Jupiter's radiation belts.

Total data returned from the probe was about 3.5 megabits. The probe stopped transmitting before the line of sight link with the orbiter was cut. The likely proximal cause of the final probe failure was overheating, which sensors indicated before signal loss. The atmosphere as the probe descended was somewhat more turbulent and hotter than expected. The probe was eventually completely destroyed. The parachute would have melted first, roughly 30 minutes later^[29], then the aluminum components after another 40 minutes of free fall. The titanium structure would have lasted 6.5 hours more before disintegrating. Due to the high pressure, the metals of the probe would finally have vaporised once their critical temperature had been reached, completely dissolving it into Jupiter's interior. A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum. ... Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ... A nephelometer is an instrument for measuring suspended particulates in a liquid. ... A Radiometer is a device used to measure the radiant flux or power in Electromagnetic radiation. ... Luminous flux or luminous power is the measure of the perceived power of light. ... The critical temperature, Tc, of a material is the temperature above which distinct liquid and gas phases do not exist. ...

Science performed by the Galileo Orbiter at Jupiter

After arriving on December 7, 1995 and completing 35 orbits around Jupiter throughout a nearly eight year mission, the Galileo Orbiter was destroyed during a controlled impact with Jupiter on September 21, 2003. During that intervening time, Galileo forever changed the way scientists saw Jupiter and provided a wealth of information on the moons orbiting the planet which will be studied for years to come. Culled from NASA's press kit, the top orbiter science results were: Image File history File links Wiki_letter_w. ... December 7 is the 341st day (342nd in leap years) of the year in the Gregorian calendar. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ... September 21 is the 264th day of the year (265th in leap years). ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ...

• Galileo made the first observation of ammonia clouds in another planet's atmosphere. The atmosphere creates ammonia ice particles from material coming up from lower depths.
• The moon Io was confirmed to have extensive volcanic activity that is 100 times greater than that found on Earth. The heat and frequency of eruptions are reminiscent of early Earth.
• Complex plasma interactions in Io's atmosphere create immense electrical currents which couple to Jupiter's atmosphere.
• Several lines of evidence from Galileo support the theory that liquid oceans exist under Europa's icy surface.
• Ganymede possesses its own, substantial magnetic field - the first satellite known to have one.
• Galileo magnetic data provide evidence that Europa, Ganymede and Callisto have a liquid-saltwater layer under the visible surface.
• Evidence exists that Europa, Ganymede, and Callisto all have a thin atmospheric layer known as a 'surface-bound exosphere'.
• Jupiter's ring system is formed by dust kicked up as interplanetary meteoroids smash into the planet's four small inner moons. The outermost ring is actually two rings, one embedded with the other. There is probably a separate ring along Amalthea's orbit, as well.
• The Galileo spacecraft identified the global structure and dynamics of a giant planet's magnetosphere.

Ammonia is a compound with the formula NH3. ... Atmospheric characteristics Atmospheric pressure trace Sulfur dioxide 90% Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter. ... Apparent magnitude: 5. ... This article or section does not adequately cite its references or sources. ... This article or section does not cite its references or sources. ... [fAgot png|thumb|200px|right|Atmosphere diagram showing the exosphere and other layers. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... It has been suggested that micrometeoroid be merged into this article or section. ... The inner satellites of Jupiter are four small moons that orbit close to Jupiter, merging with its planetary ring. ... Amalthea (am-əl-thee-ə, IPA: , Greek Αμάλθεια) is the third moon of Jupiter in order of distance from the planet, and the fifth in order of discovery. ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ...

Other science conducted with Galileo

The Galileo Star Scanner

The star scanner was a small optical telescope used to provide the spacecraft with an absolute attitude reference. It was also able to serendipitously make scientific discoveries.^[30] In the prime mission, it was found that the star scanner was able to detect high energy particles as a noise signal. These data were eventually calibrated to show the particles were predominantly > 2 MeV electrons that were trapped in the Jovian magnetic belts.

A second discovery occurred in 2000. The star scanner was observing a set of stars which included the second magnitude star Delta Velorum. At one point, this star dimmed for 8 hours below the star scanner's detection threshold. Subsequent analysis of Galileo data and work by amateur and professional astronomers showed that Delta Velorum is the brightest known eclipsing binary, brighter at maximum than even Algol.^[31] It has a primary period of 45 days and the dimming is just visible with the naked eye. 2000 (MM) was a leap year starting on Saturday of the Gregorian calendar. ... Animation showing how an eclipsing binary stars light intensity changes as they orbit An eclipsing binary star is a binary star in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses. ... Algol (β Per / Beta Persei) is a bright star in the constellation Perseus. ...

A final discovery occurred during the last two orbits of the mission. When the spacecraft passed the orbit of Jupiter's moon Amalthea, the star scanner detected unexpected flashes of light that were reflections from moonlets. None of the individual moonlets were sighted twice, hence no orbits were determined and the moonlets did not meet the International Astronomical Union requirements to receive designations.^[32] It is believed that these moonlets most likely are debris ejected from Amalthea and form a tenuous, and perhaps temporary, ring. Amalthea, in Greek mythology, is the foster-mother of Zeus. ...

Image taken by Galileo of Earth during GOPEX test clearly showing bright laser pulses coming from a transmitting telescope on the night side. Galileo's imager was panned downward during the exposure to separate the pulses, thus blurring earth's image on the right.

Download high resolution version (650x613, 18 KB)Image taken by Galileo spacecraft during the GOPEX experiment This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Download high resolution version (650x613, 18 KB)Image taken by Galileo spacecraft during the GOPEX experiment This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...

Remote detection of life

The late Carl Sagan, pondering the question of whether life on Earth could be easily detected from space, devised a set of experiments in the late 1980s using Galileo's remote sensing instruments to determine if life indeed could be detected during the first Earth flyby of the mission in December of 1990. After data acquisition and processing, Sagan et al. published a paper in Nature in 1993 detailing the results of the experiment. Galileo had found what are now referred to as the "Sagan criteria for life"; these were: strong absorption of light at the red end of the visible spectrum (especially over continents) which was caused by absorption by chlorophyll in photosynthesizing plants, absorption bands of molecular oxygen which is also a result of plant activity, infrared absorption bands caused by the ~1 micromole per mole (µmol/mol) of methane in Earth's atmosphere (a gas which must be replenished by either volcanic or biological activity) and modulated narrowband radio wave transmissions uncharacteristic of any known natural source. Galileo's experiments were thus the first ever controls in the newborn science of astrobiological remote sensing. ^[33] Insert non-formatted text here Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer and astrobiologist and a highly successful popularizer of astronomy, astrophysics, and other natural sciences. ... Nature is one of the most prominent scientific journals, first published on 4 November 1869. ... Dymaxion map by Buckminster Fuller shows land mass with minimal distortion as only one continuous continent A continent (Latin continere, to hold together) is a large continuous mass of land on the planet Earth. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ...

The Galileo optical experiment

In December of 1992 during Galileo's second gravity assist flyby of Earth, another groundbreaking yet almost entirely unpublicized experiment was done using Galileo to assess the possibility of optical communication with spacecraft by detecting pulses of light from powerful lasers which were to be directly imaged by Galileo's CCD. The experiment, dubbed Galileo OPtical EXperiment or GOPEX,^[34] used two separate sites to beam laser pulses to the spacecraft, one at Table Mountain Observatory in California and the other at the Starfire Optical Range in New Mexico. The Table Mountain site used a frequency doubled Neodymium-Yttrium-Aluminium Garnet (Nd:YAG) laser operating at 532 nm with a repetition rate of ~15 to 30 Hz and a pulse power (FWHM) in the tens of megawatts range, which was coupled to a 0.6 meter Cassegrain telescope for transmission to Galileo, the Starfire range site used a similar setup with a larger transmitting telescope (1.5 m). Long exposure (~0.1 to 0.8 s) images using Galileo's 560 nm centered green filter produced images of Earth clearly showing the laser pulses even at distances of up to 6,000,000 km. Adverse weather conditions, restrictions placed on laser transmissions by the U.S. Space Defense Operations Center (SPADOC) and a pointing error caused by the scan platform acceleration on the spacecraft being slower than expected (which prevented laser detection on all frames with less than 400 ms exposure times) all contributed to the reduction of the number of successful detections of the laser transmission to 48 of the total 159 frames taken. Nonetheless, the experiment was considered a resounding success and the data acquired will likely be used in the future to design laser "downlinks" which will send large volumes of data very quickly, from spacecraft to Earth. The scheme is already being studied (as of 2004) for a data link to a future Mars orbiting spacecraft.^[35] A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... Nonlinear optics is the branch of optics that describes the behaviour of light in nonlinear media, that is, media in which the polarization P responds nonlinearly to the electric field E of the light. ... General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ... General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Atomic mass 88. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Standard atomic weight 26. ... Garnet is a group of minerals that have been used since the Bronze Age as gemstones and abrasives. ... Nd:YAG is an acronym for Neodymium-doped Yttrium Aluminum Garnet, a compound that is used as the lasing medium for certain solid-state lasers. ... In telecommunication, a full width at half maximum (FWHM) is an expression of the extent of a function, given by the difference between the two extreme values of the independent variable at which the dependent variable is equal to half of its maximum value. ...

Asteroid encounters

NASA image of 951 Gaspra

Source : NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Source : NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

First asteroid encounter: 951 Gaspra

On October 29, 1991, two months after entering the asteroid belt, Galileo performed the first ever asteroid encounter by passing about 1,600 kilometers (1,000 miles) from 951 Gaspra at a relative speed of about 8 kilometers per second (18,000 mph). Several pictures of Gaspra were taken along with measurements using the NIMS instrument to indicate composition and physical properties. The last (and best) two images were played back to Earth in November 1991 and June 1992. The imagery revealed a cratered and very irregular body about 19 by 12 by 11 kilometers (12 by 7.5 by 7 miles). The remainder of data taken, including low resolution images of more of the surface, were transmitted in late November 1992.^[36] October 29 is the 302nd day of the year (303rd in leap years) in the Gregorian calendar. ... 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ...

Second asteroid encounter: 243 Ida and Dactyl

NASA image of 243 Ida. The tiny dot to the right is its moon, Dactyl.

Twenty-two months after the Gaspra encounter, on August 28, 1993, Galileo flew within 2,400 kilometers (1,500 miles) of asteroid 243 Ida. The probe discovered that Ida had a small moon, dubbed Dactyl, only 1.4 km in diameter which was the first asteroid moon discovered. Measurements using Galileo's solid state imager, magnetometer and NIMS instrument were taken. From subsequent analysis of data, Dactyl appears to be an SII subtype S type asteroid and is spectrally different from 243 Ida. It is hypothesized that Dactyl may have been produced by partial melting within a Koronis parent body (Ida belongs to the "Koronis" family of asteroids that travels in the main Asteroid Belt between Mars and Jupiter) while the 243 Ida region escaped such igneous processing. NASA image of 243 Ida and Dactyl. ... NASA image of 243 Ida and Dactyl. ... August 28 is the 240th day of the year in the Gregorian Calendar (241st in leap years), with 125 days remaining. ... 1993 (MCMXCIII) was a common year starting on Friday of the Gregorian calendar and marked the Beginning of the International Decade to Combat Racism and Racial Discrimination (1993-2003). ... The Koronis Family is a family of asteroids in the Main Belt. ...

Spacecraft malfunctions

Main antenna failure

Laboratory tests verified that holding ribs 9, 10, and 11 in the stowed position most nearly modeled the spacecraft telemetry.

For reasons which are not currently known, and in all likelihood will never be known with certainty, Galileo's high-gain antenna failed to fully deploy after its first flyby of Earth. Investigators speculate that during the time that Galileo spent in storage after the Challenger disaster, the lubricants evaporated, or the system was otherwise damaged. Engineers tried thermal cycling the antenna, rotating the spacecraft up to its maximum spin rate of 10.5 rpm, and "hammering" the antenna deployment motors - turning them on and off repeatedly - over 13,000 times; all attempts failed to open the high-gain antenna. Fortunately Galileo had an additional low-gain antenna that was capable of transmitting information back to Earth, though since it transmitted a signal isotropically, the low-gain antenna's bandwidth was significantly less than the high-gain antenna's would have been; the high-gain antenna was to have transmitted at 134 kilobits per second whereas the low-gain antenna was only intended to transmit at about 8 to 16 bits per second. Galileo's low-gain antenna transmitted with a power of about 15 to 20 watts, which, by the time it reached Earth, and had been collected by one of the large aperture (70 m) DSN antennas, had a total power of about -170 dBm or 10 zeptowatts (10 × 10⁻²¹ watts).^[37] Through implementation of sophisticated data compression techniques, arraying of several Deep Space Network antennas and sensitivity upgrades of receivers used to listen to Galileo's signal, data throughput was increased to a maximum of 160 bits per second. The data collected on Jupiter and its moons was stored in the on board tape recorder, and transmitted back to Earth during the long apogee portion of the probe's orbit using the low-gain antenna. At the same time, measurements were made of Jupiter's magnetosphere and transmitted back to Earth. The reduction in available bandwidth reduced the total amount of data transmitted throughout the mission to about 30 gigabytes and reduced the number of pictures that were transmitted significantly; in all, only around 14,000 images were returned. Galileo spacecraft high gain antenna ribs stuck. ... Galileo spacecraft high gain antenna ribs stuck. ... The high-gain antenna (HGA) is an antenna with a focused, narrow radiowave beam width. ... A lubricant (colloquially, lube, although this may also refer to personal lubricants) is a substance (usually a liquid) introduced between two moving surfaces to reduce the friction and wear between them. ... The low-gain antenna (LGA) is an antenna with a broad radiowave beam width. ... Isotropic means independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. ... This article or section does not cite its references or sources. ... Deep Space Network (DSN) is an international network of radio antennas that supports interplanetary spacecraft missions, and radio and radar astronomy observations for the exploration of the solar system and the universe. ... Sony reel-to-reel tape recorder. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... A gigabyte (symbol GB) is a unit of measurement in computers of one thousand million bytes (the same as one billion bytes in the short scale usage). ...

Tape recorder anomalies and remote repair

Since Galileo's high-gain antenna failed to open in 1991 the mission was forced to use the low-gain antenna for all communication to earth. This meant that data storage to Galileo's tape recorder for later compression and playback was absolutely crucial in order to obtain any substantial information from the planned Jupiter and moon flybys. In October of 1995, Galileo's 114 megabyte (914,489,344 bits^[38]), four-track digital tape recorder which was manufactured by Odetics Corporation, remained stuck in rewind mode for 15 hours before engineers learned what happened and sent commands to shut it off, after recording an image of Jupiter. Though the recorder itself was still in working order the malfunction possibly damaged a length of tape at the end of the reel. This section of tape was subsequently declared "off limits" to any future data recording and was covered with 25 more turns of tape to secure the section and reduce any further stresses, which could tear it. Because it happened only weeks before Jupiter Orbit Insertion, the anomaly prompted engineers to sacrifice data acquisition of almost all of the Io and Europa observations during Jupiter Orbit Insertion in order to focus solely on recording data sent from the Jupiter probe descent. A megabyte is a unit of information or computer storage equal to exactly one million bytes. ... Atmospheric characteristics Atmospheric pressure trace Sulfur dioxide 90% Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter. ... Apparent magnitude: 5. ...

In November of 2002, after completion of the mission's only encounter of Jupiter's moon Amalthea, problems with playback of the tape recorder would again plague the spacecraft. About 10 minutes after closest approach of the flyby Galileo stopped collecting data, shut down all of its instruments, and went into "safe mode"; apparently as a result of exposure to Jupiter's extremely high radiation environment. Though most of the Amalthea data was already written to tape, it was found that the recorder refused to respond to commands telling it to play back data. Through careful analysis^[39] after weeks of troubleshooting of an identical flight spare of the recorder on the ground, it was determined that the cause of the malfunction was a reduction of light output in three infrared Optek OP133^[40] light emitting diodes located in the drive electronics of the recorder's motor encoder wheel. The GaAs LEDs had been particularly sensitive to proton irradiation induced atomic lattice displacement defects, which greatly decreased their effective light output and caused the drive motor's electronics to falsely believe the motor encoder wheel was incorrectly positioned. Galileo's flight team then began a series of "annealing" sessions, where current was passed through the LEDs for hours at a time to heat them to a point where some of the crystalline lattice defects would be shifted back into place, thus increasing the LED's light output. After about 100 hours of annealing and playback cycles, the recorder was able to operate for up to an hour at a time. After many subsequent playback and cooling cycles, the complete transmission back to Earth of all recorded Amalthea flyby data was successful. Amalthea (am-əl-thee-ə, IPA: , Greek Αμάλθεια) is the third moon of Jupiter in order of distance from the planet, and the fifth in order of discovery. ... External links LEd Category: TeX ... Gallium arsenide (GaAs) is a chemical compound composed of gallium and arsenic. ... Quartz crystal Synthetic bismuth crystal Insulin crystals Gallium, a metal that easily forms large single crystals A huge monocrystal of potassium dihydrogen phosphate grown from solution by Saint-Gobain for the megajoule laser of CEA. In chemistry and mineralogy, a crystal is a solid in which the constituent atoms, molecules... Annealing, in metallurgy and materials science, is a heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. ...

Other radiation related anomalies

The uniquely harsh radiation environment at Jupiter caused over 20 anomalies in addition to the incidents expanded upon above. Despite exceeding its radiation design limit by at least a factor of three, the spacecraft survived all the anomalies. Several of the science instruments suffered increased noise while within about 700,000 km of Jupiter. The quartz crystal used as the frequency reference for the radio suffered permanent frequency shifts with each Jupiter approach. A spin detector failed and the spacecraft gyro output was biased by the radiation environment. The SSI camera began producing totally white images when the spacecraft was hit by the exceptional 'Bastille Day' coronal mass ejection in 2000 and subsequently on close approaches to Jupiter. The most severe effect was a reset of the computers (called a CDS despun bus reset) that occurred when the spacecraft was either close to Jupiter or in the region of space magnetically downstream of the Earth. Work-arounds were found for all of these problems. A composite image showing two CMEs (at 2 oclock and 8 oclock), with the sun at center. ...

Near failure of atmospheric probe parachute

The atmospheric probe deployed its first parachute about one minute later than anticipated, resulting in a small loss of upper atmospheric readings. Through review of records, the problem was later determined to likely be faulty wiring in the parachute control system. The fact that the chute opened at all was attributed to luck [2].

Future of Jupiter exploration

After the end of the Galileo mission and in the light of the discoveries Galileo made, NASA was planning a future Jupiter mission called JIMO: Jupiter Icy Moons Orbiter. The JIMO mission was in its early planning stage and liftoff was not to be expected before 2017. However, President Bush's 2006 budget request to Congress essentially cut funding for JIMO. Another spacecraft planned to orbit Jupiter is Juno, due to launch by 2010 to study Jupiter's atmosphere and magnetic field. Artistss Conception of Jupiter Icy Moons Orbiter The Jupiter Icy Moons Orbiter (JIMO) was a proposed spacecraft designed to explore the icy moons of Jupiter. ... 2017 (MMXVII) will be a common year starting on Sunday of the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... Juno at Jupiter Juno is a NASA mission to Jupiter planned to cost roughly $700 million and scheduled to launch by June 30, 2010. ... This article or section does not cite its references or sources. ...

New Horizons, launched in 2006, passed by Jupiter on February 28, 2007, at 05:43 GMT, while enroute to Pluto and other trans-Neptunian objects in the Kuiper Belt. The New Horizons flyby will provide opportunities for additional scientific research of the Jupiter system. New Horizons is a robotic spacecraft mission conducted by NASA. It is expected to be the first spacecraft to fly by and study the dwarf planet Pluto and its moons, Charon, Nix and Hydra. ... February 28 is the 59th day of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... A trans-Neptunian object (TNO) is any object in the solar system with all or most of its orbit beyond that of Neptune. ...

See also

• Pioneer 10
• Pioneer 11
• Voyager program
• Cassini probe

Pioneer 10 was the first spacecraft to travel through the asteroid belt, and was the first spacecraft to make direct observations of Jupiter. ... Position of Pioneer 10 and 11 Pioneer 11 was the second mission to investigate Jupiter and the outer solar system and the first to explore the planet Saturn and its main rings. ... Voyager Project redirects here. ... This is an artists concept of Cassini during the Saturn Orbit Insertion (SOI) maneuver, just after the main engine has begun firing. ...

References

1997 (MCMXCVII) was a common year starting on Wednesday of the Gregorian calendar. ... September 17 is the 260th day of the year (261st in leap years). ... For the Manfred Mann album, see 2006 (album). ... December 12 is the 346th day (347th in leap years) of the year in the Gregorian calendar, with 19 days remaining. ... 1996 (MCMXCVI) was a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... December 6 is the 340th day (341st on leap years) of the year in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... December 12 is the 346th day (347th in leap years) of the year in the Gregorian calendar, with 19 days remaining. ... For the Manfred Mann album, see 2006 (album). ... December 12 is the 346th day (347th in leap years) of the year in the Gregorian calendar, with 19 days remaining. ... shelby was here 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... October 19 is the 292nd day of the year (293rd in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... December 12 is the 346th day (347th in leap years) of the year in the Gregorian calendar, with 19 days remaining. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ... December 8 is the 342nd day (343rd in leap years) of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 6 is the 126th day of the year in the Gregorian calendar (127th in leap years). ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

• Galileo home page
• Jupiter Icy Moons Orbiter
• Site explaining the LGA bandwidth upgrades from the Parkes Observatory
• GOPEX site from JPL
• NASA site on Galileo life detection experiments
• Mission to Jupiter: a History of the Galileo Project, by Michael Meltzer, NASA SP 2007-4231 (on-line book)