LAST summer, towards the end of a speech to the Society of Space Explorers (an elite bunch of men and women who have distinguished themselves by travelling in space), the new Nasa administrator, Daniel S Goldin, held up a small plaque. 'When I moved into the administrator's office five months ago,' he said, 'I found this plaque in a display case - covered with dust. It is the Apollo 11 patch and bears the signatures of Neil Armstrong, Buzz Aldrin and Mike Collins. On the top is written: 'Carried to the Moon aboard Apollo 11. Presented to the Mars 1 crew.' Ladies and gentlemen, it is time to take this plaque to Mars.'

In January, the planet which was the subject of that optimistic inscription is the star of the show. When Venus bows out of the firmament at about 8.30pm during January, Mars takes over. On 7 January the Red Planet is 'at opposition' - directly facing the Earth in its orbit - and at its closest point to our planet. At midnight it stands high in the south, its red colour in striking contrast to the blue-white stars of Gemini. It is hard to ignore - and this is an attitude that the space agencies are beginning to share.

Days after Mr Goldin made his speech, the Mars Observer probe blasted off from Cape Canaveral on a mission to map the planet in detail. Due to reach its destination in August, the probe will undertake orbital manoeuvres until December before starting its photographic reconnaissance. Its cameras will record details as small as cars on a motorway.

The Mars Observer, the first US probe to visit the Red Planet for 16 years, is only the beginning. In the now international spirit of space collaboration, it is equipped to relay data to Earth from the next vanguard of Mars-bound hardware: the Russian/French Mars 94 and Mars 96. These two missions boast some daring new technology, and experiments from Europe and the United States, as well as from Russia. Mars 94 consists of an orbiter, which will release two landers, and two craft that can penetrate and analyse the Martian surface.

The mission on board Mars 96 will explore the sands of Mars. A helium-filled French balloon will drift across the Martian landscape during the day, photographing the surface and making measurements; in the cool of the nights it will hover above one spot, before taking off for pastures new under the warming rays of the rising Sun. The balloon is complemented by a Russian-built rover, tested in one of Earth's most 'Martian' terrains, Death Valley in California. Using video cameras and other sensors to cope with cliffs and ditches, the rover can look beneath and around any features of

interest.

Representatives of all the agencies involved in Mars exploration - a total of 200 people - met recently to discuss how to avoid too much duplication. The goals are an international manned mission to Mars, then the construction of a permanent Martian base.

But sending robots to Mars is one thing; sending people is another. On a two-year round trip, the effects of microgravity on the human body will be profound; cosmic radiation on the way will be hazardous; but worst of all may be the psychological strains of a journey twice as long as any so far.

But volunteers are plentiful. There will always be those such as the astronaut Mike Collins, who says: 'I don't want to live with a lid over my head . . . it is within us to look up into the night sky and be curious, and within us to commit our bodies to follow our eyes.'

'Is there life on Mars?' asks Nasa's Daniel Goldin. Maybe not now. But there will be.

The Planets

On 19 January, Venus reaches its greatest eastern elongation and shines like a beacon in the south- western sky. At 41 degrees from the Sun, we see it swinging wide in its orbit and setting more than three hours after sunset. Possessors of small telescopes will be able to see the planet shrink in phases from just bigger than half to a fat crescent.

In the same part of the sky as Venus, but much lower down to the right, is ring-world Saturn. A fixture of the sky since last summer, by the end of January it will have disappeared behind the Sun.

At opposition on 7 January, Mars is closest to the Earth and directly opposite the Sun in the sky, a combination that makes it the brightest it will be on this particular apparition. For the first two weeks of January it forms a striking equal-sided triangle with the blue-white 'twins', Castor and Pollux, that gradually elongates as Mars drifts west.

Jupiter is rising at llpm by the end of the month and, once it has cleared the haze around the horizon, it can be seen to be about half a magnitude brighter than Mars. The Moon, just before last quarter, is close to Jupiter on the morning of the 14th.

Meteors

During the first few days of each new year, the Earth ploughs through a cloud of debris in space that gives rise to the Quadrantids meteor shower. As in other meteor showers, the debris harmlessly burns up through friction (causing 'shooting stars') as it streams to Earth. But the Quadrantids are a meteor shower with a difference, because the comet or asteroid that produces all the debris has never been identified. The cloud of debris evidently has a dense core, because the meteor rate is sharply peaked. This year, lucky watchers may see up to 100 meteors an hour on the evening of 3 January, but the 'storm' will be shortlived.

The stars

The constellation of Auriga - an ancient Babylonian star-group meaning 'the charioteer' - rides overhead in the bleak midwinter. Its chief star, Capella, is yellow like our Sun, and is the seventh-brightest in the sky. To the right of Capella lies a tiny triangle of fainter stars: the Haedi (kid-goats) that the charioteer carries on his shoulder. Two of the kids, zeta and epsilon, have secret lives behind their faint facades. Zeta (lower right of the Haedi) is a gigantic orange star circled every 972 days by a small blue companion star. When they hide behind one another, the brightness of the whole system drops by almost a factor of two.

Epsilon (at the top of the Haedi) is another 'eclipsing binary' in Auriga. It, too, fades to half its normal brilliance when eclipsed, but this happens only once every 27 years and takes a year to complete.

It used to be thought that the 'eclipsing star' which took so long to move across its companion had to be the biggest in the Universe: so large that if it were placed in the Solar System, it would stretch all the way to Saturn. The latest observations, however, indicate that the eclipser is some kind of shell or gas cloud; it may even be a new solar system in the process of formation.

Diary

1 3.38am Moon at first quarter

4 Earth at perihelion (closest to Sun)

7 Mars at opposition

8 12.37pm full Moon

15 4.01am Moon at last quarter

19 Venus at greatest eastern

elongation

22 6.27pm new Moon

30 11.20pm Moon at first quarter