The bright, ginger-colored star in the evening sky in recent weeks is not a star at all – it’s Mars. We’re humming past it roughly 43 million miles away, in one of the close encounters that occur every 2 1/4 years.

A closer approach of about 35 million miles in August 2003 was an opportunity to launch a spacecraft carrying people, but interplanetary travel got put on the back burner decades ago. Mars, nonetheless, has intrigued people for centuries, and longer, and recently NASA was directed to jump-start plans to send people there. Mars is an Earth-like planet, meaning you could walk around on it if you had the right equipment.

The surface of Mars would be strange to see. You’d clamber down a ladder from a spindly descent vehicle onto a rolling plain of red rock and dirt, as dead as any moonscape. The air, seen from behind a helmet, is a faded orange color caused partly by reflections from rusty dust. The atmosphere is only about a tenth as thick as the Earth’s, and so as you look out on the desert, a weird clarity magnifies everything, like the clarity that disoriented the astronauts on the moon. Things are different here, though.

A boulder to your right seems nearby, but you can’t tell exactly. You walk toward it. Your steps are light because Mars’ gravity is about a third of the Earth’s. By the time you get to the boulder, you have an idea of what 30 feet means on Mars. At an undeterminable distance farther out, a tiny whirlwind spins up some sand in ghostlike motion, then disappears.

Beyond, a hill with blocky rocks cuts a skyline. You think it’s within walking distance, but you’re not sure. The rust-red rocks jut up in a rough circle, like certain stone wreckage on English hilltops. Maybe holes are bored in the rocks, into which someone poured oil and then lit wicks, and crouched vigilantly watching the martian desert.

This is crazy. They are obviously just rocks that have lain there for millions of years, visited only by wind, sand, sunlight and freezing cold.

But people have been wondering for centuries if there’s life on Mars. The first realistic sketches of the surface were made from early telescope observations in 1659. In the 1700s the English astronomer William Herschel noted Mars seemed to have seasons and thought this could mean it was inhabited. In 1877 Giovanni Schiaparelli drew detailed maps including what he called “canali” – Italian for “channels” – interwoven over the whole planet.

The word canali was translated in the English press as “canals,” which implied trenches deliberately dug and filled with water. Following this lead, the American astronomer Percival Lowell conjectured the canals were carrying water from the ice-bound poles to population centers. One of his students calculated the capital city of Mars was at 30 degrees south latitude, 90 longitude.

As it turned out, there are no canals. But space probes have shown that water flowed in torrents on Mars millions of years ago, and some of it is locked up in ice under the surface now. The main significance of this is that in the right conditions, water spawns life.

You’d like to hike across the rock-strewn gravel to that hilltop and look at those stones, which by now seem almost like archaeological artifacts. But Mission Control has other tasks for you.

Your boots are leaving latticed tracks in the sand. You look back toward the descent vehicle. Its sloping sides are covered in red dust kicked up by the landing. Its legs shine in the westering sunlight.

Across unmoving undulations of red desert, is the horizon. The sun is lowering. The sky fades to a nasturtium color, and the rocks seem to grow in the twilight. The boulder’s shadow bends across the rubble toward you.

You kick up some dust with your boot and watch it filter through the evening air and settle in your tracks. This sand could be full of the fossils of ancient martian microbes.

Your mission is to find out.