Man's old dream about life on Mars seemed to fade for good in 1965 when the first closeup pictures of the red planet were radioed back to earth by the U.S. spacecraft Mariner 4. The photographs revealed a barren planet that looked as dead as the moon. Lately, this view of Mars has been radically revised. Contrary to the first photographic impression, U.S. scientists told an international space conference in Madrid last week, Mars is still undergoing sharp climatic changes. Violent geological activity has left scars all across its crust and, most significant, there may be enough water on its surface to support the evolution of primitive life.
Russian Failure. These dramatic findings have come from the extraordinarily productive Mariner 9 spacecraft. Still alive and transmitting, the 1,200-lb. robot has sent back more than 6,800 pictures since it began circling the planet last November. By patiently matching and assembling these photographs, scientists at Caltech's Jet Propulsion Laboratory have put together a jigsaw-puzzle-like map of a strip of Mars extending 30° above and below the equator as well as an overall view of its south polar cap. Indeed, detailed photographs, showing features as small as 100 yards across, were among the highlights of the 15th annual session of the international Committee on Space Research, attended by more than 1,000 scientists from 35 countries.
Russian delegates had less to crow about. A Soviet TV-equipped instrument package did reach Mars last December in company with Mariner 9. The Russian ship landed safely and even began sending signals. But the intense dust storm that was buffeting the planet at the time completely obscured the view. ("If you know, for example, what London fog is like, then you have an idea what was there," explained Mikhail Marov, head of the Soviet Mars program.) After sending signals for only 20 seconds, the Russian vehicle apparently tumbled over in the high winds (perhaps as strong as 300 m.p.h.), leaving its antenna pointing in the wrong direction for any further transmissions.
High above, beyond that turbulent atmosphere, Mariner 9 had better luck. Once the storm subsided, it focused on a remarkable range of Martian features:
> An area of at least four towering volcanoes, some of which may still be showing signs of activity. They are dominated by gigantic Nix Olympica, with an upper rim estimated to be more than three times as tall as Mt. Everest, the earth's highest peak.
> Highly jumbled chaotic terrain, including many canyons, some of which seem to have been carved out by flowing water in the recent geological past. The major feature of the region is a giant gorge that is reminiscent of the Great Rift Valley in East Africa. It is 2,500 miles long, 75 miles wide and nearly four miles deep.
> A heavily cratered region, presumably pounded by meteorites, that scientists are comparing to the lunar highlands. Earlier photographs of this pock-marked area led investigators to concludeprematurelythat Mars was a planetary version of the moon.