The Planetary Society

65 N. Catalina Avenue, Pasadena, CA 91106-2301 (626) 793-5100 Fax (626)

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For Release: November 30, 1999

Contact: Susan Lendroth

When Will We First Hear the Sounds of Mars?

Everyone will be listening when the Mars Polar Lander touches down on the
Martian surface, Friday, December 3, carrying aboard the spacecraft The
Planetary Society’s Mars Microphone. However, we may have to wait until a
couple of days into the mission to hear the first sounds from Mars.

The first opportunity to receive sound data will be Friday night (PST) when
the Mars Polar Lander sends data from the spacecraft instruments, but there
is a possibility that sounds from Mars will not be included in that first
data dump.

This possible delay is the result of a truncated Earth test months before
the spacecraft’s launch when the microphone may not have been reset to
clear its memory of recorded Earth-based test sounds. If that is the case,
the first sound data from Mars may not be received on Earth until Saturday
evening, December 4.

The possible lack of reset to the microphone only became apparent in the
last several days during the final operations readiness tests of the
lander’s scientific payload.

Even if the microphone were not reset after the test, there is still some
chance that sounds recorded right after landing may override some of the
Earth-based test sounds in the microphone’s memory. The Mars Microphone is
programmed to record the loudest sounds it hears, and Friday’s microphone
recording period is timed to coincide with the noisy motion of the lander’s
main camera. If the Martian sounds are louder than the test sounds, it is
possible that a mixture of test and Mars sounds will be sent back to Earth
on Friday night.

If sounds from Mars are received Friday night, the goal will be to process
the data overnight for release on Saturday morning, December 4, at 10:00 AM

On Saturday, the day after landing, the command sequence already programmed
on the spacecraft includes a microphone reset, which will wipe the memory
clean for new sounds. On Saturday, the timing of the microphone recording
period should correlate with the deployment of the robotic arm — another
noisy event. The microphone team will try to process those sounds for
release on Sunday, December 5.

Later in the mission, perhaps on Monday, December 6, an attempt will be
made to record natural Martian sounds during a quiet time on the
spacecraft. In the absence of mechanical noises, we might be able to hear
the sounds of Mars, such as blowing dust or wind.

The Planetary Society hopes to release the sounds at Planetfest ’99 at the
Pasadena Center, December 3-5, 1999. The Society is sponsoring Planetfest
to enable the public to witness the first few days of the mission. A
festival of space exploration, Planetfest will open at noon, December 3,
just prior to the spacecraft’s landing at 12:14 PM (PST).

In addition to the live event in Pasadena, Planetfest Online will cover the
mission and other Planetfest activities at The Planetary Society’s web site

The microphone is the first privately funded experiment on a planetary
mission. It is situated onboard Russia’s LIDAR experiment, which is the
first Russian experiment to fly on a US planetary mission.



Register in advance for press credentials with Susan Lendroth at
(626)793-5100 (ext. 214) or by e-mail at


Carl Sagan, Bruce Murray and Louis Friedman founded the Society in 1979 to
advance the exploration of the solar system and to continue the search for
extraterrestrial life. With 100,000 members in over 140 countries, the
Society is the largest space interest group in the world.

Linda Wong

The Planetary Society

65 N. Catalina Ave.

Pasadena, CA 91106-2301

Tel: (626) 793-5100 ext. 236

Fax: (626) 793-5528