SMART-1 was a Swedish-designed
European Space AgencyThe European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...
satelliteIn 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
orbitIn 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
MoonThe 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
UTCCoordinated 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
KourouKourou 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 GuianaFrench 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 thrusterIn 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-1350PPS-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
xenonXenon 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
litrepic|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
ionAn 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 impulseSpecific 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-vIn 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
gThe 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 maneuverIn 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
perigeePerigee 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
euroThe 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. dollarsThe 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 CorporationThe 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
LinköpingLinköping 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 FoingBernard 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 telescopeAn 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 fluorescenceX-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:
magnesiumMagnesium 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...
,
siliconSilicon 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
aluminiumAluminium 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
ironIron 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...
,
calciumCalcium 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
titaniumTitanium 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 variabilitySolar 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 spectrometerInfrared 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
olivineThe 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
pyroxeneThe 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 PasanenPertti 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 bandThe 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 1Eurobird 3 is a communications satellite that offers capacity for broadband and broadcast services in Europe. It is owned by Eutelsat....
, by an
Ariane 5Ariane 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 GuianaFrench 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 orbitA 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
xenonXenon 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 osculatingIn 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
perigeePerigee 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 L
1 Lagrangian PointThe 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
UTUniversal 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 orbitIn 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 osculatingIn 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 analysisSpectroscopy 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
NorthNorth 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
BepiColomboBepiColombo 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
MercuryMercury 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 ResearchThe 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 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 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 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 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