Mars is a planet that has received considerable attention from Hollywood over the years. For decades, in the mid to late 20th century, Hollywood would produce movie after movie depicting Martians as little green men who were nasty Earth invaders. Sometimes men from Mars simply sported green face paint, but they almost always wore a jumpsuit of some type.

Occasionally, though, Martians were not small or green. In movies called "Flying Disc Man From Mars" (1950) and "Flight to Mars" (1951), Martians looked just like us. However, in a 1960s movie called "The Angry Red Planet." there's no shortage of scary Martian creatures. Martian Monsters included giant green bat-spiders, man-eating plants, amorphous slithering blobs with one eye, and three-eyed Martians with devil horns.

In "The War of the Worlds," the classic 1898 H.G. Wells novel, invading Martians are described as having a quivering, V-shaped mouth, huge brains with tentacles, intense eyes, and an oily brown skin. Martians used robots for their manual labor.

In the 1953 movie, "Invaders From Mars," Hollywood shows Martians for the first time in color. While the Martian Master is more akin to Wells' literary creature, the workers are humanoid, with ping-pong eyeballs and three fingers. And they're unique in their oversized hoodies with zippers running up the backs.

However, in the 1960s, television would provide a much more positive impression of Martians. In 1963, in the comedy series "My Favorite Martian", lovable actor Ray Walston was only made distinct from humans by the retractable antennae sitting on top of his otherwise normal human head.

I was thinking about how all of this Hollywood science fiction and hype has shaped our thinking of Mars, as I watched the successful landing of NASA's robotic spaceship on the planet's surface the other day. I wondered if the late 20th century Hollywood science fiction writers could ever imagine a day when a spacecraft from Earth would actually enter the Martian atmosphere. They could certainly never envision a spaceship that would be traveling at a speed of 13,000 miles per hour just seven short minutes before actually landing on a planned spot on the Martian surface.

In fact the entry into Mars' atmosphere and landing on the planet's surface were thought to be the most dangerous part of the Phoenix mission by NASA scientists. However, the spacecraft would land perfectly in the Vastitas Borealis Plains within the Martian Arctic Circle. This mission had been planned since the Mars Odyssey detected frozen water below the planet's surface in 2002. The Phoenix Mars landing is at a latitude comparable to that of northern Alaska on Earth.

The purpose of the Phoenix mission is to discover not only the history of the planet's water and ice, but also whether the region could support microbial life. Crucial to this question will be tests for complex, carbon-based chemicals (organics) in the soil and signs that the ice periodically melts. Other soil tests will determine abundances of different minerals, and the laboratory will also subject dust grains to microscopic examination.

Phoenix will be stationary for three months on Mars as it carries out these scientific operations on the planet's surface. Phoenix's stereo camera, located on its 2-meter (6.6-foot) mast, will use two "eyes" to reveal a high-resolution perspective of the landing site's geology. It will also provide range maps for use in choosing where to dig. Multi-spectral capability will enable the identification of local minerals.

The solar-powered craft will deploy a robotic arm to dig down vertically through the soil toward the planet's icy crust. The arm was designed to deliver samples of Martian soil to the spacecraft's wet chemistry lab and tiny ovens for scientific analysis. The samples will be heated to release volatiles that can be examined for their chemical composition and other characteristics. One goal is to check whether subsurface samples hold carbon-containing compounds that are essential ingredients of life.

To increase scientific understanding of Martian atmospheric processes, Phoenix will scan the atmosphere up to twelve miles in altitude, obtaining data about the formation, duration, and movement of clouds, fog, and dust plumes. It also carries temperature and pressure sensors.

A better understanding of Mars is important to scientists since the planet is a primary long-term target for human exploration. Current plans are for a colonization of the Moon by NASA during the next decade. An outpost on the lunar surface would make a future launch of a manned spacecraft to Mars a distinct possibility in the decades that follow.

The next ninety days will determine the ultimate success of the first robotic spacecraft to land on Mars in over a decade. The Phoenix will surely become a trailblazer for future missions that will continue to explore the planet‘s surface. As far as all those movies about little green men and other creatures from Mars are concerned, real science is now about to replace science fiction. Indeed, NASA's Phoenix spacecraft has arrived on the surface of Mars. Its arrival marks the end of Martians as portrayed in Hollywood fiction.