What's Next for Mars; The Future of Space Exploration; Scientific American Presents; by Zorpette; 6 Page(s)

An invasion of Earth by a Martian fleet has been one of the staples of science fiction, from H. G. Wells's 1898 The War of the Worlds to the 1996 motion picture Mars Attacks! But although there have been many imaginative outpourings from countless writers and directors, few foresaw that the invasion would actually be in the reverse direction, by a robotic fleet from Earth.

Over the next 10 years the National Aeronautics and Space Administration and its European partners plan to send at least four orbiters and four landers to the Martian surface, culminating in a mission that will use highly sophisticated rovers to collect samples of rock and soil that will be delivered to Earth by 2008. The agenda holds out the possibility of seven or so additional trips to the Red Planet, including several relatively inexpensive "micromissions" and a second series of flights that would return dozens more samples between 2008 and 2012. The ambitious series of probes is in addition to the Mars Global Surveyor spacecraft, which has been orbiting the planet since 1997, and a Japanese orbiter called Planet-B, launched last July on a two-year mission to study Mars's atmosphere and ionosphere. Not since the heady days of the space race to the moon more than three decades ago has a single celestial body been the target of so many spacecraft in so short a period.