Europe Reaches The Moon (SMART-1)

worth reading -



Ron wrote:

http://www.esa.int/esaCP/SEM2S8WJD1E_index_0.html

Europe reaches the Moon
European Space Agency
16 November 2004

ESA PR 60-2004. ESA's SMART-1 is successfully making its first orbit of
the Moon, a significant milestone for the first of Europe's Small
Missions for Advanced Research in Technology (SMART) spacecraft.

A complex package of tests on new technologies was successfully
performed during the cruise to the Moon, while the spacecraft was
getting ready for the scientific investigations which will come next.
These technologies pave the way for future planetary missions.

SMART-1 reached its closest point to the lunar surface so far - its
first "perilune" - at an altitude of about 5000 kilometres at 18:48
Central European Time (CET) on 15 November.

Just hours before that, at 06:24 CET, SMART-1's solar-electric
propulsion system (or "ion engine") was started up and is now being
fired for the delicate manoeuvre that will stabilise the spacecraft in
lunar orbit.

During this crucial phase, the engine will run almost continuously for
the next four days, and then for a series of shorter burns, allowing
SMART-1 to reach its final operational orbit by making ever-decreasing
loops around the Moon. By about mid-January, SMART-1 will be orbiting
the Moon at altitudes between 300 kilometres (over the lunar south pole)
and 3000 kilometres (over the lunar north pole), beginning its
scientific observations.

The main purpose of the first part of the SMART-1 mission, concluding
with the arrival at the Moon, was to demonstrate new spacecraft
technologies. In particular, the solar-electric propulsion system was
tested over a long spiralling trip to the Moon of more than 84 million
kilometres. This is a distance comparable to an interplanetary cruise.

For the first time ever, gravity-assist manoeuvres, which use the
gravitational pull of the approaching Moon, were performed by an
electrically propelled spacecraft. The success of this test is important
to the prospects for future interplanetary missions using ion engines.

SMART-1 has demonstrated new techniques for eventually achieving
autonomous spacecraft navigation. The OBAN experiment tested navigation
software on ground computers to determine the exact position and
velocity of the spacecraft using images of celestial objects taken by
the AMIE camera on SMART-1 as references. Once used on board future
spacecraft, the technique demonstrated by OBAN will allow spacecraft to
know where they are in space and how fast they are moving, limiting the
need for intervention by ground control teams.

SMART-1 also carried out deep-space communication tests, with the KaTE
and RSIS experiments, consisting of testing radio transmissions at very
high frequencies compared to traditional radio frequencies. Such
transmissions will allow the transfer of ever-increasing volumes of
scientific data from future spacecraft. With the Laser Link experiment,
SMART-1 tested the feasibility of pointing a laser beam from Earth at a
spacecraft moving at deep-space distances for future communication
purposes.

During the cruise, to prepare for the lunar science phase, SMART-1 made
preliminary tests on four miniaturised instruments, which are being used
for the first time in space: the AMIE camera, which has already imaged
Earth, the Moon and two total lunar eclipses from space, the D-CIXS and
XSM X-ray instruments, and the SIR infrared spectrometer.

In all, SMART-1 clocked up 332 orbits around Earth. It fired its engine
289 times during the cruise phase, operating for a total of about 3700
hours. Only 59 kilograms of xenon propellant were used (out of 82
kilograms). Overall, the engine performed extremely well, enabling the
spacecraft to reach the Moon two months earlier than expected.

The extra fuel available also allowed the mission designers to
significantly reduce the altitude of the final orbit around the Moon.
This closer approach to the surface will be even more favourable for the
science observations that start in January. The extra fuel will also be
used to boost the spacecraft back into a stable orbit, after six months
of operations around the Moon, in June, if the scientific mission is
extended.

For more information please contact:

ESA Media Relations Division
Tel: +33(0)1.53.69.7155
Fax: +33(0)1.53.69.7690