Messenger
An artist's interpretation of the MESSENGER spacecraft at Mercury.
Organization	NASA
Mission type	Fly-by(s)/orbit
Flyby of	Earth, Venus, & Mercury
Satellite of	Mercury
Orbital insertion date	(eta) March 18, 2011
Launch date	August 3, 2004
Launch vehicle	Delta II 7925H-9. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Events 37 - The Roman Senate annuls Tiberius ' will and proclaims Caligula emperor 2011 ( MMXI) will be a Common year starting on Saturday of the Gregorian calendar. Events 8 - Roman Empire General Tiberius defeats Dalmatians on the river Bathinus. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " 5
NSSDC ID	2004-030A
Webpage	messenger.jhuapl.edu
Mass	1,093 kg (2,410 lb)
Power	450 W (Mercury orbit nominal)

The MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) probe is a NASA spacecraft, launched August 3, 2004 to study the characteristics and environment of Mercury from orbit. The International Designator (or NSSDC ID) is an international naming convention for Satellites It consists of the launch year a 3-digit incrementing launch number The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program A spacecraft is a Vehicle or machine designed for Spaceflight. Events 8 - Roman Empire General Tiberius defeats Dalmatians on the river Bathinus. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star Specifically, the mission is to characterize the chemical composition of Mercury's surface, the geologic history, the nature of the magnetic field, the size and state of the core, the volatile inventory at the poles, and the nature of Mercury's exosphere and magnetosphere over a nominal orbital mission of one Earth year. Use in chemistry In Chemistry, the empirical formula of a Chemical compound is a simple expression of the relative number of each type of Atom The geologic time scale is a chronologic schema (or idealized Model) relating Stratigraphy to time that is used by Geologists and other In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges The planetary core consists of the innermost layer(s of a Planet. This article is about geographic magnetic and other poles on planets and other astronomical bodies The exosphere is the uppermost layer of the atmosphere. On Earth, its lower boundary at the edge of the Thermosphere is estimated to be 500 km to A magnetosphere' is a highly magnetized region around and possessed by an Astronomical object. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun

The mission is the first to visit Mercury in over 30 years; the only previous probe to visit Mercury was Mariner 10, which completed its mission in March 1975. Mariner 10 was a robotic Space probe launched on November 3, 1973 to fly by the planets Mercury and Venus. The MESSENGER has vastly improved scanning capability, with cameras capable of resolving surface features to 18 meters (59 ft) across compared to the 1. A camera is a device used to capture images either as still Photographs or as sequences of moving images ( Movies or Videos. Image resolution describes the detail an Image holds The term applies equally to Digital images film images and other types of images The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International A foot (plural feet or foot; symbol or abbreviation ft or sometimes &prime – the prime symbol) is a non-SI unit 6 kilometres (0. 99 mi) resolution of the Mariner 10. MESSENGER will also be able to image the entire planet; Mariner 10 was only able to observe one hemisphere that was lit during its flybys. In Astronomy and Navigation, the celestial sphere is an imaginary rotating Sphere of "gigantic Radius "

The contrived acronym MESSENGER was chosen because Mercury was the messenger of the gods according to Roman mythology. Acronyms, initialisms, and alphabetisms are Abbreviations that are formed using the initial components in a phrase or name "Alipes" redirects here For the Centipede Genus, see Alipes (centipede. The MErcury Surface Space ENvironment GEochemistry and Ranging ( MESSENGER) probe is a NASA Spacecraft, launched August 3, 2004 Roman mythology, or more appropriately Latin mythology, refers to the mythological beliefs of the Italic people inhabiting the region of Latium and its

Travel to Mercury

Launch of MESSENGER.

The Boeing Delta II rocket carrying MESSENGER lifted off from Cape Canaveral Air Force Station, Florida at 02:15:56 EDT on August 3, 2004. The Boeing Company is a major Aerospace and defense corporation originally founded by William E In Spaceflight, a launch vehicle or carrier rocket is a Rocket used to carry a payload from the Earth's surface into Outer space. The Cape Canaveral Air Force Station (CCAFS is a detachment of the 45th Space Wing (45 SW Patrick AFB provides headquarters functions from the 45 SW a major airfield Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the The Eastern Time Zone ( ET) of the Western Hemisphere falls mostly along the east coast of North America and the west coast of South America Events 8 - Roman Empire General Tiberius defeats Dalmatians on the river Bathinus. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " An hour later, NASA confirmed that MESSENGER had successfully separated from the third stage booster and commenced its roundabout route to Mercury.

Travel to Mercury requires an extremely large velocity change, or delta-v, because Mercury lies deeper in the Sun's gravity well; a spacecraft traveling to Mercury is greatly accelerated as it falls toward the Sun, so there must be a mechanism to slow it. In Astrodynamics, the term delta-v, literally "change in velocity" (see symbol delta) has a specific meaning it is a Scalar which takes In Physics, a gravity well is the Gravitational potential field around a massive body (a particular kind of Potential well) Further, because Mercury does not have an atmosphere, it is impossible to aerobrake on arrival; the spacecraft must use rockets to slow down enough to go into orbit. Aerobraking is a Spaceflight maneuver that reduces the high point of an Elliptical orbit ( Apoapsis) by flying the vehicle through the Atmosphere To make the trip feasible, MESSENGER makes extensive use of gravity assist maneuvers. In Orbital mechanics and Aerospace engineering, a gravitational slingshot, gravity assist or swing-by is the use of the relative movement and These reduce the energy (and thus fuel) requirements, but greatly prolong the trip. Finally, for additional fuel savings, the thrust used for insertion into orbit about Mercury will be minimized, resulting in a notably elliptical orbit. In Astrodynamics or Celestial mechanics an elliptic orbit is a Kepler orbit with the eccentricity greater than 0 and less than 1 Besides the advantage of saving fuel, such an orbit allows the spacecraft to measure solar wind and magnetic fields at a variety of distances from the planet, yet still get close-up measurements and photographs of the surface. Fuel is any material that is burned or altered in order to obtain energy

MESSENGER performed a successful Earth swingby a year after launch, on 2 August 2005, with the closest approach at 19:13 UTC at an altitude of 2,347 kilometers (1,458 statute miles) over central Mongolia. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Events 338 BC - A Macedonian army led by Philip II defeated the combined forces of Athens and Thebes in the Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Mongolia (mɒŋˈɡoʊliə, literally Mongol country/nation,) is a Landlocked Country in East On December 12, 2005, a 524 second long burn ('Deep-Space Maneuver' or 'DSM-1') of the large thruster adjusted the trajectory for the upcoming Venus swing-by. Events 627 - Battle of Nineveh: A Byzantine army under Emperor Heraclius defeats Emperor Khosrau II 's Persian Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. ^[1] MESSENGER made its first flyby of Venus at 08:34 UTC on October 24, 2006 at an altitude of 2,992 kilometers (1,859 mi). Events 69 - Second Battle of Bedriacum, forces under Antonius Primus the commander of the Danube armies loyal to Vespasian, defeat Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. A second flyby of Venus was made at 23:08 UTC on June 5, 2007 at an altitude of 338 kilometers (210 mi). Events 70 - Titus and his Roman Legions breach the middle wall of Jerusalem in the Siege of Jerusalem Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. On October 17, 2007, 'Deep-Space Maneuver-2' or 'DSM-2' was executed successfully, putting MESSENGER on target for its first flyby of Mercury. Events 539 BC - King Cyrus The Great of Persia marches into the city of Babylon, releasing the Jews from almost Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. ^[2] MESSENGER made a flyby of Mercury on 14 January 2008 (closest approach 200 km above surface of Mercury at 19:04:39 UTC),^[3] and will make two more flybys of Mercury on October 6, 2008 and September 29, 2009, successively slowing down the spacecraft. Events 1129 - Formal approval of the Order of the Templar at the Council of Troyes. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 105 BC - Battle of Arausio: The Cimbri inflict the heaviest defeat on the Roman army of Gnaeus Mallius Maximus 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 522 BC - Darius I of Persia kills the Magian usurper Gaumâta securing his hold as king of the Persian Empire. This article is about the year For the film see 2009 Lost Memories. Mercury orbit insertion will be on March 18, 2011, beginning a year-long orbital mission. Events 37 - The Roman Senate annuls Tiberius ' will and proclaims Caligula emperor 2011 ( MMXI) will be a Common year starting on Saturday of the Gregorian calendar.

MESSENGER's trajectory.

During the Earth flyby, MESSENGER imaged the Earth and Moon and used its atmospheric and surface composition spectrometer to look at the Moon. The particle and magnetic field instruments investigated the Earth's magnetosphere. A magnetosphere' is a highly magnetized region around and possessed by an Astronomical object.

The spacecraft was originally scheduled to launch during a 12-day window that opened May 11, 2004, but on March 26, 2004, NASA announced that a later launch window starting at July 30, 2004 with a length of 15 days would be used. Events 330 - Byzantium is renamed ''Nova Roma'' during a dedication ceremony but is more popularly referred to as Constantinople "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1026 - Pope John XIX crowns Conrad II as Holy Roman Emperor. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1419 - First Defenestration of Prague. 1502 - Christopher Columbus lands at Guanaja in the Bay Islands off "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " ^[4] This significantly changed the trajectory of the mission and will delay the arrival at Mercury by two years. The original plan called for three swingby maneuvers past Venus, with Mercury orbit insertion scheduled for 2009. The new trajectory features one Earth flyby, two Venus flybys, and three Mercury flybys before orbit insertion on March 18, 2011. Orbit insertion is a deceleration or acceleration maneuver performed by a Spacecraft designed to allow the spacecraft to be captured into Orbit around a Planet Events 37 - The Roman Senate annuls Tiberius ' will and proclaims Caligula emperor 2011 ( MMXI) will be a Common year starting on Saturday of the Gregorian calendar.

The navigation team is lead by KinetX, Inc. KinetX, Inc is a privately held Tempe, Arizona based engineering technology software development and business consulting firm specializing in aerospace systems of Tempe, AZ. KinetX is the first private company to be responsible for navigation of a NASA deep space mission. In that role, they are responsible for determining all trajectory adjustments throughout the probe's flight through the inner solar system ensuring that MESSENGER arrives at Mercury with the proper velocity for orbit insertion.

Mercury observation plan

MESSENGER's first image of the side of Mercury which was never seen by Mariner 10, from a distance of about 17,000 miles (27,000 km).

The nominal orbit has a periapsis of 200 km (120 mi) at 60 degrees N latitude, and an apoapsis of 15,193 km (9,440 mi), a period of 12 hours and an inclination of 80 degrees. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from Inclination in general is the Angle between a Reference plane and another plane or axis of direction The periapsis will slowly rise due to solar perturbations to over 400 km (250 mi) at the end of 88 days (one Mercury year) at which point it will be readjusted to a 200 km (120 mi), 12 hour orbit via a two burn sequence. Data will be collected from orbit for one Earth year, the nominal end of the primary mission. Global stereo image coverage at 250 meters/pixel resolution is expected. The mission should also yield global composition maps, a 3-D model of Mercury's magnetosphere, topographic profiles of the northern hemisphere, gravity field to degree and order 16, altitude profiles of elemental species, and a characterization of the volatiles in permanently shadowed craters at the poles. In Mathematics, the spherical harmonics are the angular portion of an Orthogonal set of solutions to Laplace's equation represented in a system of

Once there, scientists hope to test a theory that the planet is shrinking, contracting in on itself as its core slowly freezes. The probe will look for signs of surface buckling on Mercury's unobserved hemisphere, as well as collect surface composition data on material that may have once spewed out of the planet's interior. The idea that Mercury's surface was somehow shrinking arose when Mariner 10 returned images of great scarps biting deep into the planet's surface. In Geomorphology, an escarpment is a transition zone between different physiogeographic provinces that involves a sharp steep Elevation differential characterized One such scarp, Discovery Rupes, cuts 1. Discovery Rupes is an Escarpment on Mercury approximately 650 kilometers (404 mile long and 2 kilometers (6562 feet high located at latitude 56 6 km (1 mi) into Mercury's crust.

Spacecraft and subsystems

MESSENGER was designed and built by Johns Hopkins University's Applied Physics Laboratory (JHU/APL). The Johns Hopkins University Applied Physics Laboratory (APL located in Laurel Maryland, is a not-for-profit university-affiliated research center employing It is a squat box (1. 27 m × 1. 42 m × 1. 85 m) with a semi-cylindrical thermal shade for protection from the Sun and two solar panel wings extending radially. In the field of Photovoltaics, a photovoltaic module is a packaged interconnected assembly of photovoltaic cells also known as Solar cells An installation of A 3. 6 m (12 ft) magnetometer boom also extends from the craft. A magnetometer is a scientific instrument used to measure the strength and/or direction of the Magnetic field in the vicinity of the instrument The total mass of the spacecraft is 1,093 kg (2,410 lb); 607. 8 kg (1,340 lb) of this is propellant (hydrazine and nitrogen tetroxide) and helium. Hydrazine is a Chemical compound with the formula N2H4 It has an Ammonia -like odor and is derived from the same industrial chemistry Nitrogen tetroxide ( dinitrogen tetroxide or nitrogen peroxide) is the Chemical compound N2O4 The structure is primarily graphite cyanate ester (GrCE) composite and consists of two vertical panels which support two large fuel tanks and two vertical panels which support the oxidizer tank and plumbing panel. The four vertical panels make up the center column and are bolted at their aft ends to an aluminum adapter. A single top deck panel mounts the LVA (large velocity adjust) thruster, small thrusters, helium and auxiliary fuel tanks, star trackers and battery. The attitude of a body is its orientation as perceived in a certain Frame of reference; providing a vector along which a spacecraft is pointing is a description of its attitude

MESSENGER assembly at Astrotech. Spacehab Inc ( is an aerospace company headquartered in Webster, Texas near the Johnson Space Center.

Main propulsion is via the 645 N (145 lb_f), 317 s bipropellant LVA thruster. The newton (symbol N) is the SI derived unit of Force, named after Isaac Newton in recognition of his work on Classical This article deals with the unit of force For the unit of mass see Pound (mass. Specific impulse (usually abbreviated I sp is a way to describe the efficiency of rocket and jet engines A bipropellant rocket engine is a Rocket engine that uses two propellants (very often liquid propellants) which are kept separately prior to reacting to form a hot Four 22 N (4. 9 lb_f) monopropellant thrusters provide spacecraft steering during main thruster burns, and ten 4 N (0. A Monopropellant rocket (or " monoprop rocket " is a Rocket that uses a single chemical as its power source and propellant 9 lb_f) monopropellant thrusters are used for attitude control. There is also a reaction wheel attitude control system. A reaction wheel is a type of Flywheel used primarily by Spacecraft to change their Angular momentum without using fuel for Rockets or other reaction The attitude of a body is its orientation as perceived in a certain Frame of reference; providing a vector along which a spacecraft is pointing is a description of its attitude Information for attitude control is provided by star tracking cameras, an inertial measurement unit, and six solar sensors. Power is provided by the solar panels, which extend beyond the sunshade and are rotatable to balance panel temperature and power generation, and provides a nominal 450 watts in Mercury orbit. The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. The panels are 70 percent optical solar reflectors and 30 percent GaAs/Ge cells. The power is stored in a common-pressure-vessel, 23-ampere-hour nickel-hydrogen battery, with 11 vessels and two cells per vessel. The ampere, in practice often shortened to amp, (symbol A is a unit of Electric current, or amount of Electric charge per second Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy

Communications are in X-band with downlink through two fixed phased array antenna clusters and uplink and downlink through medium- and low-gain antennas on the forward and aft sides of the spacecraft. The X band is part of the Microwave region of the Electromagnetic spectrum. This article is about general theory and electromagnetic phased array An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into The low-gain antenna (LGA is an antenna with a broad radiowave beam width Passive thermal control, primarily a fixed opaque ceramic cloth sunshade, is utilized to maintain operating temperatures near the Sun. Radiators are built into the structure and the orbit is optimized to minimize infrared and visible light heating of the spacecraft from the surface of Mercury. Radiators and convectors are types of Heat exchangers designed to transfer Thermal energy from one medium to another for the purpose of cooling Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Multilayer insulation, low conductivity couplings, and heaters are also used to maintain temperatures within operating limits.

Five science instruments are mounted externally on the bottom deck of the main body: the Mercury Dual Imaging System (MDIS), Gamma-Ray and Neutron Spectrometer (GRNS), X-ray Spectrometer (XRS), Mercury Laser Altimeter (MLA), and Atmospheric and Surface Composition Spectrometer (MASCS). The Energetic Particle and Plasma Spectrometer (EPPS) is mounted on the side and top deck and the magnetometer (MAG) is at the end of the 3. 6 meter boom. Radio Science (RS) experiments will use the existing communications system.

MESSENGER's onboard computer system is based on the Integrated Electronics Module (IEM), a device that combines core avionics in a single box. Avionics means "aviation electronics" It comprises electronic systems for use on aircraft artificial satellites and spacecraft comprising Communications The spacecraft carries a pair of identical IEMs for backup purposes; both house a 25 megahertz main processor and 10 MHz fault protection processor. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. All four are radiation-hardened IBM RAD6000 processors, based on the IBM POWER1 CPU architecture (similar to that of older Macintoshes). Radiation hardening is a method of designing and testing electronic components and systems to make them resistant to damage or malfunctions caused by high-energy Subatomic particles The RAD6000 radiation-hardened Single board computer, based on the IBM RISC Single Chip POWER is a RISC Instruction set architecture designed by IBM. Macintosh, commonly nicknamed Mac is a Brand name which covers several lines of Personal computers designed developed and marketed by Apple Inc The RAD computers, slow by current personal computer standards, are state of the art for the radiation tolerance required on the MESSENGER mission. A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated For data storage, the spacecraft carries two solid-state recorders (one backup) able to store up to one gigabyte each. A data storage device is a device for recording (storing information (data A solid-state drive ( SSD) is a Data storage device that uses solid-state memory to store persistent Data. A gigabyte (derived from the SI prefix Giga-) is a unit of Information or Computer Its main processor collects, compresses, and stores on the recorder images and other data from MESSENGER's instruments, which can then be sent back to Earth.

Results

An image of part of the previously unseen side of the planet

MESSENGER has completed its first Mercury flyby successfully, taking pictures with both the wide angle and narrow angle cameras as well as using some of its other sensors. Preliminary image results from this first pass can be viewed at JHUAPL's MESSENGER Science Photos page. The Johns Hopkins University Applied Physics Laboratory (APL located in Laurel Maryland, is a not-for-profit university-affiliated research center employing

References

• NSSDC. NSSDC Master Catalog: Spacecraft: MESSENGER. Greenbelt, Maryland: National Space Science Data Center.

Notes

External links

• MESSENGER Web Site - official site.
• MESSENGER Mission Page - official information regarding the mission on the nasa.gov website.
• MESSENGER Mission Profile by NASA's Solar System Exploration
• Video from MESSENGER as it departs Earth.
• Mercury Flyby 1 Visualization Tool - see simulated views of the instrument observations planned during the flyby.
• NSSDC Master Catalog entry.