Sometimes it is a good idea to look back at where we’ve been – even when what we can expect to see is a pillar of salt.

The Aquarius mission, described elsewhere in these pages, is a reminder that a good deal of scientific discovery lies in the renewed examination of the familiar. In the case of the mission that islander Gary Lagerloef sends skyward in 2008, the salinity of our planet’s oceans – a critical contributor to Earth’s climate, well known but sparsely measured – will be mapped for the first time, in just eight days.

That’s a treasure trove of information, and it’s made possible by one of NASA’s most overlooked extraterrestrial enterprises: unmanned, near-earth scientific study. When most of us picture the explorers of space, we see the human faces – Shepard, Grissom and Glenn, and more recently, the crews of Challenger and Columbia; or else we imagine the robotic wonders of the Mars missions, which probe with seeming sentience a fascinatingly inhospitable world.

What we don’t picture are the workhorses of our orbital fleet – the hundreds of scientific and communication satellites that have, since the launch of Sputnik, expanded our reach to the furthest imagined corners of the planet. We forget to see them as explorers, and Earth as a strange new world still to explore.

Nowhere is that strangeness more palpable than in our planet’s oceans. Remarkably, the bulk of the world’s surface is, in some ways, as alien as the Martian landscape we are currently mining for signs of water. The oceans are a hotbed of research into the extremes of life – marine worlds that survive below polar ice and in the boiling-acid environment of deep-sea fumeroles. And, as the recent sequencing of 1.2 million genes in a bucketful of water from the Sargasso Sea (the entire human genome runs to a mere 30,000) testifies, that life is still mostly unknown.

In his 1962 speech at Rice University, President John F. Kennedy called space our “new ocean,” a frontier that would “serve to organize and measure the best of our energies and skills.” For the generation or two that grew up thinking of ‘Enterprise’ and ‘Beagle’ as names of spacecraft, not of ships, it may be equally true that the oceans are our “new space,” where scientists pilot the missions and test the waters.

As islanders, we may better appreciate – or more easily take for granted – our dependence on those waters. Here, as elsewhere, water supplies – ultimately inseparable from the health of our marine environment – are the subject of increasing study, and concern. Water was the focus of a recent issue of Yes Magazine, and the theme for the ABC/BILT environmental conference on March 20. It is also at the heart of the city’s ongoing update of its Critical Areas Ordinance, a body of regulations mostly devoted to water quality issues.

The inquiry enabled by Aquarius is grounded in these concerns, and in the need to balance our short-term life requirements with the long-term health of the ecosystem. To repeat Lagerloef’s dictum, “we live on this planet.”

While this well-meaning spirit cannot remove the possibility that scientific data will become the tool of right- or left-wing social agendas, perhaps it can defeat the skepticism with which the concept of “best available science” is often viewed.

In December 1968, Frank Borman, Jim Lovell and Bill Anders, the crew of Apollo 8, became the first humans to see the crescent Earth rise over the lunar landscape. Those of us living in this age of Aquarius may look back to the science of our time as the moment we truly took stock of what makes the Earth, our only home, sparkle like a blue jewel among the planets.