July 2, 1998. Copyright, 1998, Graphic News. All rights reserved

JAPANESE SPACECRAFT TO PROBE ATMOSPHERE OF MARS
By Oliver Burkeman

LONDON, July 2, Graphic News: THE possibility that Mars could once have sustained life will be further investigated by a spacecraft due to be launched on Saturday from Kagoshima in southern Japan.
The 540kg Planet-B orbiter, funded by the Japanese Institute of Space and Aeronautical Science, will be carried into space aboard JapanÕs M-5 rocket. It will orbit the moon twice, fly past Earth to gather speed from the gravitational pull, and then use that momentum to slingshot towards Mars, reaching the planetÕs orbit by October next year.
Once in orbit, Planet-B will gather data on the Martian atmosphere, which is now too thin and too dominated by carbon dioxide for life to exist. Scientists are especially interested in how the atmosphere interacts with the Ôsolar windÕ Ð streams of electrically-charged hydrogen atoms, or ions, which are emitted from around the sun and are thought to have thinned and depleted the oxygen in the Martian atmosphere.
Understanding how this interaction works will help them Ôread backÕ in history to discover whether the atmosphere ever was thick enough, and contained enough oxygen, to have sustained life. It could also help explain climate change on Earth.
The mission is part of a renewed effort to discover the secrets of the ÔRed PlanetÕ Ð first successfully orbited in 1964 by NasaÕs Mariner 4 Ð which includes the U.S. Mars Surveyor project, the first element of which launches in December, and the European Space AgencyÕs Mars Express, scheduled to launch in 2003. Nasa hopes to send a manned mission to the planet by 2020.
The thesis that life once thrived on Mars has been strongly supported by evidence of underground water there today, leading scientists to speculate that water once existed on the surface. Huge excitement was generated in 1996 when scientists announced they had discovered evidence of microbial life on Mars in a meteorite discovered in the Antarctic. That finding has since been heavily disputed, but enthusiasm for the search is undiminished.
Several other experiments will be undertaken by the Planet-B, which will carry a 33kg payload of scientific instruments contributed by the U.S., Sweden, Germany, France and Canada, as well as Japan. /ENDS

Sources: Nasa (www.nasa.gov), Planetary Society (+1 626 793 5100)