Rosetta to Fly By Earth on March 4

http://www.esa.int/esaCP/SEMMTBYEM4E_index_0.html

ESA's comet chaser to fly by Earth
European Space Agency
23 February 2005

ESA's comet-chaser Rosetta will make a fly-by of planet Earth on 4
March
2005, and sky watchers should be able to see it with telescopes or
binoculars if the sky is clear! Read on for details of ESA's 'Rosetta
Up
Close' photo contest.

Rosetta is approaching Earth from an area in the sky between the
constellations Leo and Sextans, and should first become visible to
large
amateur telescopes around 26 February 2005.

The spacecraft will make its closest approach to Earth at about 23:10
CET and come within 1900 kilometres, at which time it will be over
Mexico, having already passed over Europe.

Watchers in Europe may have best evening view

On the evening of the closest approach, sky watchers in Europe will be
favourably placed to follow this event using smaller telescopes or
binoculars. Unfortunately, Rosetta is not expected to become visible to
the naked eye from Europe as it will still be about 10 000 kilometres
away until it disappears below the horizon.

However, amateur astronomers using video or photo-imaging in
conjunction
with a telescope should have a great viewing opportunity - weather
permitting. They may even be able to see Rosetta's solar panels, which
extend over 32 metres; the high-gain antenna may also be
distinguishable.

After sunset on 4 March, it will appear to travel from south east to
south west, moving from the constellation Sextans towards the setting
Sun, crossing the complete sky. It will move faster as it heads west,
disappearing below the horizon around 23:00 CET. As seen from Europe it
will only reach a 'magnitude' of about +8 or +9 on the brightness scale
used by astronomers. This is dimmer than a typical faint star and not
readily apparent to the eye.

Rosetta swings between Earth and Mars

This fly-by manoeuvre will swing the three-tonne Rosetta spacecraft
around our planet and out towards Mars, where it will make a fly-by on
26 February 2007, only to come back again to Earth. Fly-bys are
necessary to accelerate the spacecraft, using planetary gravity, such
that the orbital velocity of the target comet can eventually be
matched.

This is the first of four planet fly-bys (three times with Earth, once
with Mars) that Rosetta will carry out in its long journey to its
target, Comet 67P/Churyumov-Gerasimenko. Rosetta will reach the comet
in
2014, enter into orbit and deliver a lander, Philae, onto the surface.

Moon to serve as 'dummy' asteroid

A number of activities are planned during the current fly-by. A few
hours before the closest approach the spacecraft will be pointed
towards
the Moon and the remote sensing and several other instruments will be
switched on for calibration purposes.

After this fly-by, one of the two Navigation Cameras will be switched
on
to test Rosetta's ability to track asteroids using the Moon as a
'dummy'
asteroid. Rosetta is scheduled to fly past two asteroids, Steins in
September 2008 and Lutetia in July 2010, during which this tracking
mode
will be used to keep the spacecraft instruments centred on target.

'Rosetta Up Close' photo contest

Sky watchers everywhere are invited to submit their photos of Rosetta
passing Earth to ESA's 'Rosetta Up Close' photo contest. Details of the
contest, rules, prizes and submission procedures will be posted shortly
on the ESA web site.