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THE JAPANESE space programme aims to reach a new stage of maturity next
week when one of its most ambitious scientific missions yet blasts off from
southern Japan. Å®ÉúСÊÓƵs hope that the new spacecraft, MUSES-A, will demonstrate
that Japan has the technology to send craft to the planets.

MUSES-A is to orbit the Moon. It will be the first Japanese spacecraft
to do so, and the first from any nation since President Bush last summer
announced a return to the Moon as one of the US’s goals in space. However,
Japanese space scientists believe the way that MUSES-A reaches the Moon
is more important than the destination itself.

A four-stage M3 rocket, developed by Japan’s Institute of Space and
Astronomical Science (ISAS), will launch the craft into an elliptical orbit
around the Earth next Tuesday. The orbit will gradually take it towards
the Moon. On 19 March, when the spacecraft is some 18 000 kilometres away,
the Moon’s gravity will cause it to shift into a lunar orbit. This technique,
called ‘swing-by’, allows spacecraft to travel farther than their original
acceleration would allow under normal conditions. The most celebrated success
of the technique was Voyager II, which ‘swung by’ Jupiter, Saturn, Uranus
and Neptune in succession.

Japan’s programme to send spacecraft to the planets is more modest than
that of Voyager II. However, according to Hitoshi Mizutani, a professor
at ISAS, the programme will claim some important firsts during the next
10 years. The institute, which is responsible for carrying out Japan’s scientific
space programme, has three planetary missions planned for the 1990s. The
first, if all goes well, will scoop the European Space Agency on bringing
back the first samples from a comet to Earth for analysis.

The idea is to launch a spacecraft in 1996 to encounter the comet Wirtanen
in March the following year, scoop samples from the dust cloud surrounding
the comet, and return them to Earth in 2001. That is the year the European
Space Agency plans to launch a mission that will land on a comet and extract
a sample of its material for return to Earth.

Venus and the Moon are the two other targets for ISAS’s planned missions.
The Venus mission, provisionally timed for 1996, will deploy balloons in
the planet’s atmosphere. The lunar mission will put two craft into orbit
around the Moon and send a penetrator containing seismic and other instruments
to the surface.

To turn these dreams into reality, ISAS will need a more powerful rocket
than the M3, which is a solid-fuel booster 28 metres long and capable only
of putting around 770 kilograms into low-Earth orbit. This was the largest
rocket ISAS was allowed to build under a restriction that the government
ended in June last year. (Japan’s other space agency, NASDA, is responsible
for building larger rockets.) The new policy allows the institute to build
rockets to any size that it can launch safely from its complex in Uchinoura,
in the southeast of Japan.