Though Mars has long intrigued humans, especially those who dream of extraterrestrial life, it has repeatedly humbled anyone rich and venturesome enough to send metallic proxies across millions of miles of space to try to learn its secrets.
The US and Russia spent billions on a dozen or so robotic craft meant to land on the planet and radio back their findings. Only three succeeded -- two Viking probes in 1976 and Mars Pathfinder in 1997.
Now comes a bold new contender. Its goal is not only to do basic science but, for the first time in a quarter century, to look for concrete signs of extraterrestrial life, ancient or modern.
The disk-like craft is the Beagle II, built on a shoestring by Britain, in partnership with the European Space Agency, and named after the ship whose voyages fed Darwin's theorizing about evolution.
The British craft weighs just 31kg, about 5 percent of Viking's weight and 8 percent of Pathfinder's. Stripped of unessential gear and backup systems, it cannot send out a rover to explore the local terrain but must instead rely on a single robotic arm to probe the site.
"We didn't have any money, so we had to think harder," said Dr. Colin Pillinger, the project's lead scientist at the Open University in Milton Keynes, England.
The lander, though small, about a meter wide when folded for travel through space, is nonetheless loaded with sensors, cameras, test chambers, a microscope, a rock grinder and a sampling arm that in theory can dig down 1.5m into the Martian soil. Getting under the weathered surface is a high priority because the harsh atmosphere of the planet (which produces its rusty color) is judged likely to destroy any life.
Beagle II is to soar into space atop a Russian rocket in early June and land on Mars in late December.
If everything goes as planned, it will explore for six months and will vie for public attention with two American craft, identical rovers that are to land in January. All three robots are to arrive more or less simultaneously because the orbits of Mars and Earth are coming into unusually close alignment.
Alternately skeptical and admiring, American experts call the British lander audacious. Its mission is extremely difficult, they say, and the lack of British know-how in the business of exploring Mars and making planetary probes raises the odds of failure.
"We have lots of experience in how difficult it is," said Dr. Bruce Murray, the former director of NASA's Jet Propulsion Laboratory, who is now at the California Institute of Technology. "The Beagle mission is taking on a very large challenge."
The National Aeronautics and Space Administration has about 23,000 employees. Britain has no similar agency. So making Beagle involved enlisting universities, trusts, syndicates,firms, and even the British National Lottery, which is helping to finance the lander's mission control center.
Mars has long been considered not only difficult to explore but alluring, given its reputation as the most likely spot in the solar system to harbor extraterrestrials. Recent hints of running water, modern volcanism and a molten core have only increased its appeal, suggesting that Mars may be able to support life.
Beagle II's developers say their relative poverty and inexperience have worked in their favor, helping them solve old problems in new ways. On the other hand, they add, whenever possible they have learned from their predecessors. For instance, Beagle II has a system of parachutes and air bags developed for landing in rough terrain, adapted from the Pathfinder system.