It was propelled by a solar-powered Hall effect thruster (Snecma PPS-1350-G) using xenon propellant, of which there was 82 kg (50 litres by volume at a pressure of 150 bar) at launch. The thrusters used an electrostatic field to ionize the xenon and accelerate the ions to a high speed. This ion engine setup achieved a specific impulse 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 of about 45 m/s. The thruster had a weight of 29 kg with a peak power consumption of 1,200 watts.
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 of acceleration). As for all ion-engine powered craft, orbital maneuvers 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 part of the orbit. The total delta-v expected over the thrusting lifetime of 5,000 hours is about 4 km/s, corresponding to a total impulse of 1.5 MN·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 euros (about 170 million U.S. dollars).
SMART-1 was designed and developed by the Swedish Space Corporation on behalf of ESA. Assembly of the spacecraft was carried out by Saab Space in Linköping. Tests of the spacecraft were directed by Swedish Space Corporation and executed by Saab Space.
SMART-1 ended its mission by being deliberately crashed onto the Moon's surface at . Scientists hope that the impact will have kicked up a large enough quantity of fresh lunar "soil" so that they may study its composition.
SMART-1 was launched September 27, 2003 together with Insat 3E and eBird 1, by an Ariane 5 rocket from the Guiana Space Centre in French Guiana. After 42 minutes it was released into a geostationary transfer 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 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.
|Epoch (UTC)||Perigee (km)||Apogee (km)||Eccentricity|| Inclination (deg)|
(to Earth equator)
|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|
|Epoch (UTC)||Periselene (km)||Aposelene (km)||Eccentricity|| Inclination (deg)|
(to Moon equator)
|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|
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.
ESA estimated that impact occurred at . 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 and South America, and places in the Pacific Ocean, but not Europe, Africa, or western Asia.
The Committee on Space Research 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".
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