Latest Round of Mars Microphone Tests Successful

The Mars Microphone has successfully gone through its latest round of testing in preparation for launch on the Mars Surveyor spacecraft in January 1999. Engineers in Denver, Colorado tested the entire system of the microphone that is part of the Russian LIDAR instrument, expected to reach the Red Planet in 1999.

Developed at the University of California at Berkeley Space Science Laboratory with funding from the Planetary Society, the Mars Microphone is a 50-gram (almost 2-ounce) device that will sample sounds on the surface of Mars.

In the latest tests, the device recorded some noise and engineers played back the data to hear what the instrument recorded. The testers instructed the Denver-based clean room personnel to shout at the microphone. Since this was shortly before the Super Bowl, the personnel proceeded to yell about Denver beating Green Bay. The microphone triggered on at the sounds of the words, recorded them, and, once the telemetry data was successfully transmitted to California, engineers replayed it and were treated to the cheers of Denver Broncos fans.

Of course, the instrument is designed to pick up more scientifically significant sounds. Because of power and data transmission limits, the instrument can only send a few short sound samples from Mars. While the system is transmitting a sample -- a process that can take a few hours or days -- it will be monitoring for other sounds. The loudest sound it has recorded during that transmission time will then be the next sample that is sent to Earth.

The Mars Microphone will also collect a more continuous record of sound levels in the form of integrated power in six filter bands. These filters are integrated for a programmable interval from 1 second to 10 minutes.

The Mars Microphone underwent a number of tests in 1997. In some tests, the memory chips, microphones, and other electronic components of the type that will be used in the instrument were exposed to radiation and heat similar to what can be expected in space. Another test exposed the microphone to a range of air pressure. The next tests should occur this summer and involve thermal-vacuum testing.