To the moon on 60 litres of 'fuel'.

100 million Euros is not much for a successful research mission to the moon, compared to the incredible cost of NASA.
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Smart 1 was launched in September 2003 as a technology demonstrator.
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It became Europe's first space science mission to use an ion engine instead of chemical combustion to reach its destination.
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The system draws power through the probe's solar wings and then uses this energy to propel the spacecraft forward by expelling charged particles of xenon. It was highly efficient, covering 100 million km in a series of looping orbits and using just 60 litres of "fuel".
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"That's remarkable when you think about it - it's the same volume of fuel as you'd put in the tank of a car; and we went all that way," said Smart 1 scientist Professor Manuel Grande of the University of Wales, Aberystwyth.
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http://news.bbc.co.uk/1/hi/sci/tech/5306204.stm
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http://www.usatoday.com/tech/science/space/2005-09-27-nasa-griffin-interview_x.htm