To paraphrase Douglas Adams and his "Hitchhiker's Guide to the Galaxy": So long, Spirit, and thanks for all the data.

JPL's Spirit rover landed on Mars in January 2004. As Times staff writer Amina Khan noted Tuesday:

Along with its twin rover Opportunity, which landed on the opposite side of the planet, it was sent to explore the Martian landscape for about three months. Yet although they were not built to survive the planet's harsh winters, the two have far outlived their life expectancies and their mission has proved wildly successful, sending back strong evidence, for example, that water once shaped Mars' surface.

But, as Khan reported, Spirit "has been stuck in Martian sand for two years and has been silent for more than a year, despite regular attempts by NASA scientists to contact it."

So it's time to say goodbye. And even though these guys are rocket scientists, they have hearts too.

Opportunity continues to send back scientific data as it crosses the Martian surface toward the crater Endeavour. But things won't be quite the same without Spirit, scientists on the mission said. "We have developed a strong emotional attachment to both of these rovers," John Callas, project manager for the rover program at JPL, said in a Tuesday news conference announcing the decision. "They are just the cutest darn things out in the solar system."

The story reminded me of the speech that was written by William Safire for President Nixon to deliver in case the Apollo 11 landing on the moon went wrong.

Titled "In event of moon disaster," it read:

Fate has ordained that the men who went to the moon to explore in peace will stay on the moon to rest in peace. These brave men, Neil Armstrong and Edwin Aldrin, know that there is no hope for their recovery. But they also know that there is hope for mankind in their sacrifice. These two men are laying down their lives in mankind's most noble goal: the search for truth and understanding. They will be mourned by their families and friends; they will be mourned by their nation; they will be mourned by the people of the world; they will be mourned by a Mother Earth that dared send two of her sons into the unknown. In their exploration, they stirred the people of the world to feel as one; in their sacrifice, they bind more tightly the brotherhood of man. In ancient days, men looked at stars and saw their heroes in the constellations. In modern times, we do much the same, but our heroes are epic men of flesh and blood. Others will follow, and surely find their way home. Man's search will not be denied. But these men were the first, and they will remain the foremost in our hearts. For every human being who looks up at the moon in the nights to come will know that there is some corner of another world that is forever mankind.

As the Apollo 1 and space shuttle Challenger and Columbia disasters demonstrated, space travel is dangerous business. And, of course, it's expensive.

In recent years, President George W. Bush and now President Obama have struggled to define America's future in manned space exploration. Both outlined goals of sending men back to the moon and then on to Mars.

Other people have suggested that unmanned rovers, like Spirit, are a better choice for exploration.

I'm not so sure. As much information as the Mars rovers have gathered, wouldn't it be more stirring to see men actually walk on the Red Planet?

Times columnist Gregory Rodriguez seconded that notion recently in "For Americans, to infinity and beyond," in which he called for America to think big again with an expanded space program.

And, of course, it's not just the United States and Russia anymore. China has its own space ambitions, with CNN reporting in 2007 that it has plans for manned lunar missions. CNN quoted then-NASA chief Michael Griffin as saying that "China will be back on the moon before we are. ... I think when that happens, Americans will not like it."

So it's probable that man will keep going into space.

But Tuesday's announcement about Spirit demonstrates one thing: Nostalgia over a doomed rover is a lot easier to take than the alternative Nixon was prepared for.

ALSO:

Fixing the economy the scientific way

For Americans, to infinity and beyond

Space: If you have the money, we have a program

Why we must reinvigorate our interest in science and how DJ Scientific could help us

-- Paul Whitefield

Photo: The deck of the Mars rover Spirit is shown in August 2005 at left. In 2007, it was already so covered in dust that it nearly vanished into the landscape. Credit: NASA