Mar. 6, 2002 New images of Comet Wirtanen's 1-km 'dirty
snowball' nucleus have been obtained with the European Southern
Observatory Very Large Telescope at Paranal (Chile). They show
this object at a distance of approx. 435 million km from the
Sun, about the same as when the Rosetta spacecraft of the
European Space Agency (ESA) arrives in 2011. The new
observations indicate that the comet has a very low degree of
activity at this point in its orbit - almost no material is seen
around the nucleus. This means that there will not be so much
dust near the nucleus as to make the planned landing
dramatically difficult. As a result of these observations ESA
will be able to refine plans for its Rosetta mission. Rosetta
will be launched next year and it will reach Comet Wirtanen in
2011. By that time the comet will be nearly as far from the Sun
as Jupiter, charging headlong towards the inner Solar System at
speeds of up to 135,000 km/h. To get there and to be able to
match the comet's orbit, Rosetta will need to be ac