There was a video coming up yesterday, promising Curiosity’s audio recordings from the surface of Mars. I instinctively clicked the link which took me to some seconds of pretty unrealistic groaning and howling and then – ok, I’ve been nicely rickrolled.
But what about real sounds from the surface of Mars? Why haven’t we heard any of these yet? The answer is simple: there’s no recording. To my knowledge, not a single Mars sound recording exists today. After getting used to seeing high definition images from Mars I was quite surprised to learn that.
There have been at least two attempts to capture Mars sounds, but unfortunately both failed. NASA’s Mars Polar Lander carried a microphone but lost contact to Earth during it’s descent to Mars in 1999.[ref]More on Mars Polar Lander communication loss: http://en.wikipedia.org/wiki/Mars_Polar_Lander#Communications_loss[/ref]
Phoenix, another NASA spacecraft, landed successfully in 2008 but the instrument carrying the microphone was not activated due to a computer card failure.[ref]Here’s a detailed explanation why Phoenix MARDI was not used http://www.msss.com/msl/mardi/news/12Nov07/index.html[/ref]
So what about Curiosity? Unfortunately, there’s no microphone on board this trip. Yes, that’s true: NASA planned a rover mission that costs US$ 2.5 billion and did not include a simple mic.
Scientific objectives and payload constraints
So why’s there no mic on board? That’s mainly because MSL is a scientific mission and has a clearly defined objective:
The overall scientific goal of the mission is to explore and quantitatively assess a local region on Mars’ surface as a potential habitat for life, past or present.[ref]MSL science goals: http://msl-scicorner.jpl.nasa.gov/ScienceGoals/[/ref]
Hence, every instrument has to work toward the overall scientific goal. Maybe there have been discussions about including a microphone in the early planning stages but the team decided that a mic would not reveal new facts about Mars’s habitability.
Also, spaceflight is extremely expensive and every extra gram costs money, so you only bring the things you really need.
Sounds from distant worlds
Though we don’t have any sounds from Mars, we do have another quite amazing audio recording. On January 14, 2005, the Huygens probe landed on Saturn’s moon Titan. And it recorded audio of its descent.
You can listen to the winds of Titan here (jump to 1:13 if you wanna skip the explanation):
Knowing that this was the actual sound of Huygens going down on Titan gave me goosebumps – real sounds from an alien world!
Titan’s atmosphere is much denser than that of Mars (and even that of Earth), so sounds recorded on Mars would be much fainter. Also, they would have a lower pitch than on Earth because Mars’s atmosphere mainly consists of carbon dioxide.
Could we somehow still get sounds from Curiosity?
This is only a thought experiment and purely speculative, so don’t take this too seriously. I thought about a way how we could make Curiosity hear, even without a microphone.
You may know so called “laser listening systems” or “laser microphones“. These surveillance devices use a laser beam to capture faint vibrations from surfaces (which are caused by the impact of soundwaves). The reflected signal can be converted into an audio signal. This way, Curiosity’s laser could potentially capture Mars sounds.
Yeah, I know that’s pretty unrealistic – but it would be super awesome if you ask me.