And now, a microphone that will speak volumes about Mars

The goal: A space sound-bite — perhaps the hiss of the wind or the crackle of an electrical discharge — that could speak volumes about the red planet. They’re not sure exactly what they will hear.

"We certainly don’t expect to hear little green men or any kind of life crawling around but in the idea of having our ears open just like we’ve had our eyes open, you don’t know what you’ll hear in terms of natural sounds," said Louis Friedman, executive director of the planetary society, which is funding the project.

"We’re adding a whole new sense…Now we’re going to have hearing and I think that’s going to make it more of a world for us to try to understand and enjoy," he said.

The 100,000-member planetary society, dedicated toexploring the solar system and searching for extra-terrestrial life, was founded by the late Carl Sagan, Friedman and space scientist Bruce Murray.

Later Sagan, a Cornell University astronomer whose PBS series "Cosmos" in 1980 made him a celebrity, wrote to NASA in 1996 suggesting that they mike a Mars mission.

"Even if only a few minutes of Martian sounds are recorded from this first experiment, the public interest will be high, and the opportunity for scientific exploration real," wrote Sagan, who died later that year. The microphone was developed for the society by University of California, Berkeley scientists Janet Luhmann, Dave Curtis and Greg Delory.

Getting the microphone on board the Mars polar lander where space is at a premium was a tough sell. But officials were won over when a Russian team agreed to incorporate the microphone into its lidar instrument already approved for the mission.

The lidar, a form of laser that will scan the atmosphere for dust and aerosols, will be the first Russianinstrument to fly aboard a US planetary mission. The instrument was built by the Russian space research institute. The collaboration stems from the "Mars together" agreement signed in 1994 by Vice President Al Gore and Russian Prime Minister Victor Chernomyrdin.

The Mars polar lander will be launched in January 1999 and is supposed to land in December near an ice-sheathed Martian polar cap. Using a robotic arm, the probe will dig up soil and study its chemical and mineral features.

The Mars microphone was constructed of largely off-the-shelf parts, including a microphone similar to those used in hearing aids. Friedman estimated that the total cost of the project is under $100,000.

The thumbnail-sized microphone is in a device that weighs less than 50 grams and uses about one-tenth of a watt in power, said Berkeley space physicist Delory.

The mike can be triggered randomly by naturally occurring sounds, or can be programmed to listen to specific lander actions, such as when the robotic arm digs in thesoil.

If all goes well, the microphone will eventually send back sound in short bursts of ten seconds or so.

"The mike itself seems pretty rugged," he said. "We learned what its limits were. You can drop it, you can shake it, you can kick it around. You can’t dip it in alcohol, we found out, and you can’t bake it too hot."

Last summer, the Mars pathfinder and its little rover, Sojourner, electrified the nation with its pictures and chemical analysis of Mars. Sojourner rolled about 90 metres and took more than 500 pictures before the lander lost contact with earth in October. The lander snapped more than 16,000 images.