Before meeting the dust storm with a planet, the Opportunity facility crossed almost 30 miles above the dangerous Martian surface. We somehow traveled with Oppy thanks to the thousands of images sent back to Earth. But what was the trip to Oppy ?
There were no microphones to transmit sounds to Opportunity or to a Spirit partner, but they must have undermined the noise, as their wheels crash over the rocks and dry dust. Fortunately for the curious of us, however, NASA's lab in Pasadena, California has test grounds on the Rover, including a large area designed to recreate the surface of Mars, called MarsYard. There, the engineering models of the rivers cross the model of the terrain. Together with sound science, we can understand what the Rivers sound like on Earth and on Mars.
Opportunity's metal wheels, each with its own bike running 2 inches above the Martian rock, created the right crack. the sound you expect from a robot with metal wheels that rolls over dirt. Meanwhile, the bigger Curiosity rover is a complete cacophony of screams, as its own metal wheels cross the rocks of MarsYard.
The difference in molecular structure components and air thickness will produce two noticeable distortions of sounds after you are a few paces from the rover, Banfffield explained. There are not enough molecules to carry the highest frequency sounds – those with the shortest wavelengths – so you will not hear sound at frequencies higher than 10,000 Hz at distant distances, the heights of their cymbals and bells brilliant quality. On the other hand, lower bass tones with frequencies around 100 Hz disappear on Mars, as some energy that would otherwise cause the wave to move forward is instead consumed by rotating the carbon dioxide molecules. Besides, you do not just stand on Mars in shorts and a T-shirt – you will carry the winds, the low-pressure atmosphere and the cold temperatures in the suit. The sounds will be a little more muted
Although we will never hear what Spirit, Opportunity or Curiosity actually sound like on Mars, there will soon be some experiments to measure the sounds of the Red Planet. The InSight vessel has already measured the Martian wind vibrations, and the Mars 2020 Marshall will bring two microphones on board so that we can finally hear the wind, rocks and milling of the metal on the surface of Mars.
And who knows, maybe one day in our lives, one will hear these sounds directly.