SMART-1
Encyclopedia
SMART-1 was a Swedish-designed European Space Agency
European Space Agency
The European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...

 satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

 that orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...

ed around the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. It was launched on September 27, 2003 at 23:14 UTC
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...

 from the Guiana Space Centre in Kourou
Kourou
Kourou is a commune in French Guiana, an overseas region and department of France located in South America.Kourou is the location of the Guiana Space Centre, France and ESA's main spaceport.-Geography:...

, French Guiana
French Guiana
French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...

. "SMART" stands for Small Missions for Advanced Research in Technology. On September 3, 2006 (05:42 UTC), SMART-1 was deliberately crashed into the Moon's surface, ending its mission.

Spacecraft design

SMART-1 was about one metre across, and lightweight in comparison to other probes. Its launch mass was 367 kg or 809 pounds, of which 287 kg (633 lb) was non-propellant.

It was propelled by a solar-powered Hall effect thruster
Hall effect thruster
In spacecraft propulsion, a Hall thruster is a type of ion thruster in which the propellant is accelerated by an electric field. Hall thrusters trap electrons in a magnetic field and then use the electrons to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the...

 (Snecma PPS-1350
Pps-1350
PPS-1350 is a Hall effect thruster, a kind of ion propulsion system for spacecraft. It was used in the SMART-1 mission to the moon. It creates a stream of electrically charged ions. The PPS-1350 was created by Snecma, a French aerospace firm, under license from Fakel, who designed the SPT-100, on...

-G) using xenon
Xenon
Xenon is a chemical element with the symbol Xe and atomic number 54. The element name is pronounced or . A colorless, heavy, odorless noble gas, xenon occurs in the Earth's atmosphere in trace amounts...

 propellant, of which there was 82 kg (50 litre
Litre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...

s by volume at a pressure of 150 bar) at launch. The thrusters used an electrostatic field to ionize the xenon and accelerate the ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s to a high speed. This ion engine setup achieved a specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

 of 16.1 kN·s/kg (1,640 seconds), more than three times the maximum for chemical rockets. Therefore 1 kg of propellant (1/350 to 1/300 of the total mass of the spacecraft) produced a delta-v
Delta-v
In astrodynamics a Δv or delta-v is a scalar which takes units of speed. It is a measure of the amount of "effort" that is needed to change from one trajectory to another by making an orbital maneuver....

 of about 45 m/s. The electric propulsion subsystem had a weight of 29 kg with a peak power consumption of 1,200 watts. SMART-1 is the first in the program of ESA's Small Missions for Advanced Research and Technology.

The solar arrays made 1,190 W available for powering the thruster, giving a nominal thrust of 68 mN, hence an acceleration of 0.2 mm/s² or 0.7 m/s per hour (i.e., just under 0.00002 g
G-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...

 of acceleration). As for all ion-engine powered craft, orbital maneuver
Orbital maneuver
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft.For spacecraft far from Earth—for example those in orbits around the Sun—an orbital maneuver is called a deep-space maneuver .-delta-v:...

s were not carried out in short bursts but very gradually. The particular trajectory taken by SMART-1 to the Moon required thrusting for about one third to one half of every orbit. When spiralling away from the Earth thrusting was done on the perigee
Perigee
Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...

 part of the orbit. At the end of the mission, the thruster had demonstrated the following capability:
  • Thruster operating time: 5000 h
  • Xenon throughput: 82 kg
  • Total Impulse: 1.1 MN-s
  • Total ΔV: 3.9 km/s


As part of the European Space Agency's strategy to build very inexpensive and relatively small spaceships, the total cost of SMART-1 was a relatively small 110 million euro
Euro
The euro is the official currency of the eurozone: 17 of the 27 member states of the European Union. It is also the currency used by the Institutions of the European Union. The eurozone consists of Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg,...

s (about 170 million U.S. dollars
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

). SMART-1 was designed and developed by the Swedish Space Corporation
Swedish Space Corporation
The Swedish Space Corporation is a comprehensive space company covering the entire field, from the definition of innovative business concepts and space projects to the development, tests and operation of the systems....

 on behalf of ESA. Assembly of the spacecraft was carried out by Saab Space in Linköping
Linköping
Linköping is a city in southern middle Sweden, with 104 232 inhabitants in 2010. It is the seat of Linköping Municipality with 146 736 inhabitants and the capital of Östergötland County...

. Tests of the spacecraft were directed by Swedish Space Corporation and executed by Saab Space. The project manager at ESA was Giuseppe Racca and the project manager at the Swedish Space Corporation was Peter Rathsman; the Principal Project Scientist was Bernard Foing
Bernard Foing
Bernard Foing is a scientist at the European Space Agency , Executive Director of the and was Principal Project Scientist for SMART-1, the first European mission to the Moon.-Biography:...

.

AMIE

The Advanced Moon micro-Imager Experiment was a miniature colour camera for lunar imaging. The CCD camera with three filters of 750, 900 and 950 nm was able to take images with an average pixel resolution of 80 m (about 260 ft). The camera weighed 2.1 kg (about 4.5 lb) and had a power consumption of 9 watts.

D-CIXS

The Demonstration of a Compact X-ray Spectrometer was an X-ray telescope
X-ray telescope
An X-ray telescope is a telescope that is designed to observe remote objects in the X-ray spectrum. In order to get above the Earth's atmosphere, which is opaque to X-rays, X-ray telescopes must be mounted on high altitude rockets or artificial satellites.-Optical design:X-ray telescopes can use...

 for the identification of chemical elements on the lunar surface. It detected the x-ray fluorescence
X-ray fluorescence
X-ray fluorescence is the emission of characteristic "secondary" X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays...

 (XRF) of crystal compounds created through the interaction of the electron shell with the solar wind particles to measure the abundance of the three main components: magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

, silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

 and aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

. The detection of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

, calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 and titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 depended on the solar activity. The detection range for x-rays was 0.5 to 10 keV. The spectrometer and XSM (described below) together weighed 5.2 kg and had a power consumption of 18 watts.

XSM

The X-ray solar monitor studied the solar variability
Solar variation
Solar variation is the change in the amount of radiation emitted by the Sun and in its spectral distribution over years to millennia. These variations have periodic components, the main one being the approximately 11-year solar cycle . The changes also have aperiodic fluctuations...

 to complement D-CIXS measurements.

SIR

The Smart-1 Infrared Spectrometer was an infrared spectrometer
Infrared spectroscopy
Infrared spectroscopy is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic...

 for the identification of mineral spectra of olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....

 and pyroxene
Pyroxene
The pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...

. It detected wave lengths from 0.93 to 2.4 µm with 256 channels. The package weighed 2.3 kg and had a power consumption of 4.1 watts.

EPDP

The Electric Propulsion Diagnostic Package was to acquire data on the new propulsion system on SMART-1. The package weighed 0.8 kg and had a power consumption of 1.8 watts.

SPEDE

The Spacecraft Potential, Electron and Dust Experiment. The experiment weighed 0.8 kg and had a power consumption of 1.8 watts. Its name was intentionally chosen so that its acronym is the same as the nickname of Spede Pasanen
Spede Pasanen
Pertti Olavi "Spede" Pasanen was a Finnish film director and producer, comedian, humorist, inventor, TV personality and practitioner of gags....

, famous Finnish movie actor, movie producer, inventor etc.

KATE

Ka band
Ka band
The Ka band covers the frequencies of 26.5–40 GHz. The Ka band is part of the K band of the microwave band of the electromagnetic spectrum. This symbol refers to "K-above" — in other words, the band directly above the K-band...

 TT&C (telemetry, tracking and control) Experiment. The experiment weighed 6.2 kg and had a power consumption of 26 watts.

Flight

SMART-1 was launched September 27, 2003 together with Insat 3E and eBird 1
Eurobird 3
Eurobird 3 is a communications satellite that offers capacity for broadband and broadcast services in Europe. It is owned by Eutelsat....

, by an Ariane 5
Ariane 5
Ariane 5 is, as a part of Ariane rocket family, an expendable launch system used to deliver payloads into geostationary transfer orbit or low Earth orbit . Ariane 5 rockets are manufactured under the authority of the European Space Agency and the Centre National d'Etudes Spatiales...

 rocket from the Guiana Space Centre in French Guiana
French Guiana
French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...

. After 42 minutes it was released into a geostationary transfer orbit
Geostationary transfer orbit
A geosynchronous transfer orbit or geostationary transfer orbit is a Hohmann transfer orbit used to reach geosynchronous or geostationary orbit....

 of 7,035 × 42,223 km. From there it used its Solar Electric Primary Propulsion (SEPP) to gradually spiral out during thirteen months.

The orbit can be seen up to October 26, 2004 at moontoday.net, when the orbit was 179,718 × 305,214 km. On that date, after the 289th engine pulse, the SEPP had accumulated a total on-time of nearly 3,648 hours out of a total flight time of 8,000 hours, hence a little less than half of its total mission. It consumed about 58.8 kg of xenon
Xenon
Xenon is a chemical element with the symbol Xe and atomic number 54. The element name is pronounced or . A colorless, heavy, odorless noble gas, xenon occurs in the Earth's atmosphere in trace amounts...

 and produced a delta-v of 2,737 m/s (46.5 m/s per kg xenon, 0.75 m/s per hour on-time). It was powered on again on November 15 for a planned burn of 4.5 days to enter fully into lunar orbit. It took until February 2005 using the electric thruster to decelerate into the final orbit 300-3,000 km above the Moon's surface. The end of mission performance demonstrated by the propulsion system is stated above.
Summary of osculating
Osculating orbit
In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space is the gravitational Kepler orbit In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space (at a given moment of time) is the gravitational Kepler orbit In astronomy,...

 geocentric orbital elements
Epoch (UTC) Perigee (km) Apogee (km) Eccentricity Inclination (deg)
(to Earth equator)
Period (h)
September 27, 2003 ~7,035 ~42,223 ~0.714 ~6.9 ~10.6833
October 26, 2003, 21:20:00.0 8,687.994 44,178.401 0.671323 6.914596 11.880450
November 19, 2003, 04:29:48.4 10,843.910 46,582.165 0.622335 6.861354 13.450152
December 19, 2003, 06:41:47.6 13,390.351 49,369.049 0.573280 6.825455 15.366738
December 29, 2003, 05:21:47.8 17,235.509 54,102.642 0.516794 6.847919 18.622855
February 19, 2004, 22:46:08.6 20,690.564 65,869.222 0.521936 6.906311 24.890737
March 19, 2004, 00:40:52.7 20,683.545 66,915.919 0.527770 6.979793 25.340528
August 25, 2004, 00:00:00 37,791.261 240,824.363 0.728721 6.939815 143.738051
October 19, 2004, 21:30:45.9 69,959.278 292,632.424 0.614115 12.477919 213.397970
October 26, 2004, 06:12:40.9 179,717.894 305,214.126 0.258791 20.591807 330.053834

After its last perigee
Perigee
Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...

 on November 2, on November 11, 2004 it passed through the L1 Lagrangian Point
Lagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...

 and into the area dominated by the Moon's gravitational influence, and at 1748 UT
Universal Time
Universal Time is a time scale based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time , i.e., the mean solar time on the Prime Meridian at Greenwich, and GMT is sometimes used loosely as a synonym for UTC...

 on November 15 passed the first periselene of its lunar orbit. The osculating orbit
Osculating orbit
In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space is the gravitational Kepler orbit In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space (at a given moment of time) is the gravitational Kepler orbit In astronomy,...

 on that date was 6,704 × 53,208 km, with an orbital period of 129 hours, although the actual orbit was accomplished in only 89 hours. This illustrates the significant impact that the engine burns have on the orbit and marks the meaning of the osculating orbit, which is the orbit that would be travelled by the spacecraft if at that instant all perturbations, including thrust, would cease.
Summary of osculating
Osculating orbit
In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space is the gravitational Kepler orbit In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space (at a given moment of time) is the gravitational Kepler orbit In astronomy,...

 selenocentric orbital elements
Epoch (UTC) Periselene (km) Aposelene (km) Eccentricity Inclination (deg)
(to Moon equator)
Period (h)
November 15, 2004, 17:47:12.1 6,700.720 53,215.151 0.776329 81.085 129.247777
December 4, 2004 10:37:47.3 5,454.925 20,713.095 0.583085 83.035 37.304959
January 9, 2005, 15:24:55.0 2,751.511 6,941.359 0.432261 87.892 8.409861
February 28, 2005, 05:18:39.9 2,208.659 4,618.220 0.352952 90.063603 4.970998
April 25, 2005, 08:19:05.4 2,283.738 4,523.111 0.328988 90.141407 4.949137
May 16, 2005, 09:08:52.9 2,291.250 4,515.857 0.326807 89.734929 4.949919
June 20, 2005, 10:21:37.1 2,256.090 4,549.196 0.336960 90.232619 4.947432
July 18, 2005, 11:14:28.0 2,204.645 4,600.376 0.352054 90.263741 4.947143

ESA announced on February 15, 2005, the endorsement of a proposal to extend the mission of SMART-1 by one year until August 2006. This date was later shifted to September 3, 2006, to enable scientific observations from Earth.

Lunar impact

SMART-1 impacted the Moon's surface as planned, on September 3, 2006 at 05:42:22 UTC, ending its mission. Moving at approximately 2,000 m/s (4,500 mph), SMART-1 created an impact visible with ground telescopes from Earth. It is hoped that not only will this provide some data simulating a meteor impact, but also that it might expose materials in the ground, like water ice, to spectroscopic analysis
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...

.

ESA estimated that impact occurred at 34°24′S 46°12′W. These numbers can be entered into NASA's World Wind, to see where on the Moon it crashed. At the time of impact, the Moon was visible in North
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and South America, and places in the Pacific Ocean, but not Europe, Africa, or western Asia.

This project has generated data and know-how that will be used for other missions, such as the ESA's BepiColombo
BepiColombo
BepiColombo is a joint mission of the European Space Agency and the Japan Aerospace Exploration Agency to the planet Mercury, due to launch in 2014. The mission is still in the planning stages so changes to the current description are likely over the next few years...

 mission to Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...

.

The Committee on Space Research
COSPAR
The Committee on Space Research was established by the International Council for Science in 1958.Among COSPAR's objectives are the promotion of scientific research in space on an international level, with emphasis on the free exchange of results, information, and opinions, and providing a forum,...

 has established rules to protect planets and moons from possible contamination by spacecraft. In response to concerns of SMART-1 contaminating the Moon, ESA claims that "every chemical element present on SMART-1 and in its instruments exists naturally on the Moon".

Important events and discoveries


  • September 27, 2003: SMART-1 launched from the European Spaceport in Kourou by an Ariane 5
    Ariane 5
    Ariane 5 is, as a part of Ariane rocket family, an expendable launch system used to deliver payloads into geostationary transfer orbit or low Earth orbit . Ariane 5 rockets are manufactured under the authority of the European Space Agency and the Centre National d'Etudes Spatiales...

     launcher.
  • June 17, 2004: SMART-1 took a test image of Earth with the camera that would later be used for Moon closeup pictures. It shows parts of Europe and Africa. It was taken on May 21 with the AMIE camera.
  • November 2, 2004: Last perigee
    Perigee
    Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...

     of Earth orbit.
  • November 15, 2004: First perilune of lunar orbit.
  • January 15, 2005: Calcium detected in Mare Crisium
    Mare Crisium
    Mare Crisium is a lunar mare located in the Moon's Crisium basin, just northeast of Mare Tranquillitatis. This basin is of the Pre-Imbrian period, 4.55 to 3.85 billion years ago. This mare is in diameter, and 176,000 km2 in area. It has a very flat floor, with a ring of wrinkled ridges...

    .
  • January 26, 2005: First close up pictures of the lunar surface sent back.
  • February 27, 2005: Reached final orbit around the Moon with an orbital period of about 5 hours.
  • April 15, 2005: The search for PEL
    Peak of Eternal Light
    Peak of Eternal Light describes a point on a body within the Solar System which is eternally bathed in sunlight. This is due to both the bodies' rotation and the point's altitude...

    s begins.
  • September 3, 2006: Mission ends with a planned crash into the Moon during orbit number 2,890.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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