ESA Science News

11 Nov 1999

Europe is going to the moon

A highly innovative and budget-priced mission to explore the moon has formally been approved by the European Space Agency. Meeting in Paris
9 and 10 November the Agency’s Science Programme Committee has
finalised all aspects of the SMART-1 project. This small lunar orbiter is the first in a new line of Small Missions for Advanced Research in
Technology to demonstrate new key technologies for future deep space missions.

The most important technology to be flown on the 350-kg spacecraft scheduled for launch at the end of 2002 as an Ariane 5 auxiliary payload
will be solar electric propulsion. This will constitute its primary propulsion to escape the Earth’s gravity, for its 17-month cruise to the
Moon and to stay in lunar orbit for six months. It will be the first time that Europe uses Solar Electric Propulsion as primary propulsion.

In recent years, electric propulsion systems have principally been used by near-Earth telecommunications satellites for small orbit
corrections. SMART-1 will employ a stationary plasma thruster which uses xenon gas as a propellant. Electrical solar power will be used to
expel the gas at very high speed, generating, by reaction, the movement of the satellite.

“Compared with conventional chemical systems, electric propulsion expends very little mass to accelerate a spacecraft. But it ejects the
propellant plasma up to ten times faster than a classical engine and so is ten times more efficient. SMART-1 is truly going to live up to its
name!” says Project Manager Giuseppe Racca.

SMART-1 will carry a Scientific and Technology Payload consisting of seven instruments. The principal objective of three of them will be to
monitor the operation of the electric propulsion system.

A diagnostic package (EPDP, provided by Laben, Italy) will characterise the plasma environment around the spacecraft; another payload
(SPEDE, from the Finnish Meteorological Institute, Helsinki) will monitor plasma variations and dust environment during the cruise and
lunar orbit phases; whilst a series of Radio Science investigations (RSIS, University of Rome) will monitor the performance of the electric
propulsion system. In addition RSIS will measure the rotational state of the Moon by combining orbit and attitude determination with accurate
imaging. The mission also carries an experimental deep-space telecommunications sub-system (KATE, Dornier Germany) operating in X and
Ka frequency bands.

The lunar science payload consists of three instruments: a compact X-ray spectrometer (D-CIXS, provided by the Rutherford Appleton
Laboratory, UK), a micro-imager (AMIE, developed in the framework of ESA’s Technology Research Programme in conjunction with CSEM
Switzerland) and an
Infrared Spectrometer (SIR, Max Planck für Aeronomie Institüt, Lindau, Germany).


[NOTE: An image supporting this article is available at]