Hear Sound from Mars via DPA Microphone

UPDATE: On Thursday, February 18, 2021, the Perseverance rover will touch down on the Martian surface and give us our first chance to hear sounds from another planet. What an amazing opportunity that will be. To read all about how DPA was chosen by NASA as the first interplanetary microphone, check out the article below. And, to watch NASA’s coverage of the landing along with their briefings and overviews, check out this site starting on Feb. 16, 2021, at 1PM EST: https://mars.nasa.gov/mars2020/timeline/landing/watch-online/

When
I found out that NASA was sending a mic to Mars to record the sound of another
planet for the very first time, I was intrigued. Like many people, my
fascination with space exploration goes back to my youth. Before Star Wars,
we had pictures of the Saturn V rockets and the Apollo Lunar Module pinned to
the corkboard in our bedrooms. And, as an audio engineer, I have an endless
fascination with how things sound. The thought of hearing what the surface of
Mars sounds like is exciting.

We’re going to be taking microphones with us. For the first time, we’re going to have that human sense on another planet.Matt Wallace, Perseverance Deputy Project Manager

NASA Jet Propulsion Laboratory – Mission Overview: NASA’s Perseverance Mars Rover

The
Mars 2020 mission launched on July 30, 2020; and, when it touches down on Mars
in 2021, we’ll get our first opportunity to hear actual sounds from Mars
through a DPA microphone. This is not the first time DPA mics have been chosen
by NASA; their collaboration goes back over 50 years. In 1970, the liftoff of
Apollo 13 was recorded with Brüel & Kjær (of which DPA is a spin-off)
measurement mics because of their ability to cleanly record extremely high
sound pressure levels (up to 170dB at 500 feet away). So, what is it about DPA
microphones that made NASA choose to take one to the red planet?

Can you spot the DPA microphone mounted to the outside of the Perseverance Mars rover? Here’s a photo of the port side of NASA’s Perseverance Mars rover taken on Nov. 16, 2019, in High Bay 1 of the Spacecraft Assembly Facility at NASA’s Jet Propulsion Laboratory in Southern California. At the top left, the rover’s remote sensing mast can be seen in the deployed position. To the right of the mast in the center of the image is the light gray high-gain antenna. At center of the image, attached to the side of the rover, is a black cable bracket with gold cabling running through it. Attached to the top of this black bracket — and gray in color — is the Entry Descent and Landing (EDL) microphone.

Why DPA?

The sound is important, no doubt, but DPA products’ ability to perform in demanding environments was paramount — to withstand the rigors and temperature extremes of space travel. To traverse pressure changes both in and out of Earth’s atmosphere in addition to the Martian atmosphere, which is 99% less dense than Earth’s. To endure temperature extremes during the seven-month voyage to Mars, which will reach -100˚C (-148˚F), and the massive vibrations incurred during not only the launch but also the Martian landing. Space travel is not an odyssey with ample room for error, so reliability is a necessity. According to René Mørch, product manager at DPA, “These products will be in space indefinitely, which is a testament to DPA’s quality and resiliency. We are honored to be a part of this mission.” The goal of the microphones and cameras was not only scientific but also to “give people on Earth a good and dramatic sense of the ride down to the surface,” according to NASA. 

Components

I’ll never forget the first time I held an MMA-A in my hand. I was flabbergasted. What an amazing and engaging piece of technology. It honestly looks like a miniature frisbee. And inside this tiny package are two preamps, digital converters, and USB output, and yet it’s capable of capturing the highest fidelity available. Astounding!

What Can We Expect to Hear?

What
might the Mars mission audio sound like? DPA asked their resident audio expert,
Eddy Bøgh Brixen, what one might expect to hear during the mission. He
emphasized that it’s anyone’s guess, but he speculated that it could possibly
sound like this:

The Inside Scoop from DPA

I
had so many questions that I reached out to René Mørch at DPA to get answers.
Here are a few of the questions I posed to DPA. The first answer was the most
shocking to me.

Q: How do you build a mic that is capable of going into space and
enduring those extreme conditions? Are there unique design considerations when
building a mic to endure the incredibly low and high temperatures? How much
modification was required to existing designs?

A: Basically, they are “off-the-shelf” components that were implemented
in the Perseverance solution. We did have to modify the mechanical layout of
the MMP-G amplifier slightly so it could be bolted to the exterior of the rover.
The MMA-A, with its round design, was also modified, again to be able to fix it
to the chassis of the rover. This unit is, however, mounted inside (in the nice
and warm interior) of the rover.

During
the process of assembling the equipment of the rover going to Mars, all parts
and the whole construction were tested rigorously before the launch, and the
DPA solution succeeded to work in all these tests (otherwise we would not be
onboard).

The fact that they are factory-standard components is a clear
statement of the quality and durability of the DPA components. NASA is not
sending anything to Mars that they don’t trust will do its job!

Q: So, you’re saying these are not unique, purpose-built mics
designed for interplanetary travel? They are the same components and mics that
Sweetwater customers buy from us? Really?

To answer the question directly, yes. The mics used on Perseverance are just like the ones anyone can buy from Sweetwater.

Components are visible on the port side of the Perseverance rover in this close-up image taken on Nov. 16, 2019, in High Bay 1 of the Spacecraft Assembly Facility at NASA’s Jet Propulsion Laboratory in Southern California. At the center of the image, attached to the side of the rover, is a black cable bracket with gold cabling running through it. Attached to the top of this black bracket — and gray in color — is the Entry Descent and Landing (EDL) microphone.

Q: When NASA reached out to DPA, did they have specific design tolerances?

A: Not many people really read (or care to read) specifications, and not many manufacturers give much information about their capsules/mics, but if you look up our specs on our website, you’ll find that our microphones (including the miniatures, subminiatures, and 4099 instrument mics) are specified from -40 to +113 degrees Fahrenheit. This makes them work within the tolerances stated without artifacts or disturbance. Also, we state that they will work in very high humidity (up to 90%), again, without any flaws.

Designing to meet such demands calls for careful selection of the materials used in the construction, as their temperature coefficients, etc. must follow each other so no single material used behaves differently when exposed to temperature changes.

All the tolerances of the components used are our regular tolerances and designs, and only the mechanical parts were altered slightly to be able to bolt it directly to the rover.

Q: Were there any accommodations required for the drastically lower atmospheric density on Mars?

A: No, there are no changes made on the DPA-supplied hardware to accommodate for the thin atmosphere on Mars.

Q: The reality that off-the-shelf DPA components are built to tolerances and standards that are adequate for space travel speaks volumes about the quality of DPA’s designs and products.

A: Our legacy is from the audio-measurement industry and hearing-aid industry where the designs must withstand harsh environments and work perfectly even in extreme situations. This background has also driven DPA to design microphone solutions you can carry to the humid jungle as well as the desert and arctic — and they are indeed used in such places!

So, again, to answer directly: We put a lot of energy and pride into designing solutions that can be used wherever you find the perfect spot for your recording or performance. In this particular case, we didn’t do anything apart from what we always do.

Be Listening

If you are as intrigued as I am, be listening as the Mars Perseverance rover touches down on the Martian surface on February 18, 2021. Tune in then to hear sounds from space unlike anything anyone has ever heard before, courtesy of NASA and DPA.

To learn more about the Perseverance rover and the instrumentation employed, check out NASA’s Rover Summary page, including an interactive 3D model of the rover.

UPDATE

November 19, 2020. NASA just released the first recording from Perseverance as it travels through deep space. This was a test of the recording equipment, and the DPA mic performed flawlessly. While you can’t hear a sound in the vacuum of deep space, you will hear vibrations from the heat rejection fluid pump picked up by the DPA mic mounted to the side of the rover.

Take a listen to the
60-second audio clip here: https://soundcloud.com/nasa/perseverance-rover-sounds.

You can read NASA’s report
here: https://mars.nasa.gov/news/8801/hear-audio-from-nasas-perseverance-as-it-travels-through-deep-space/

DPA and You

If you’ve never experienced the sound and quality of DPA mics, then I think it’s about time. These are fine audio instruments that reward the listener with sublime sound; also, they will last for generations — even if your grandchildren decide to take them to Mars!

I bought my first DPA mics (B&K at that time) nearly 40 years ago — a stereo pair of 4006s that I used for everything from piano and acoustic guitar to drum overheads, strings, and choirs. They were (and still are) brilliant microphones that excelled in every application. I’ve been a huge fan ever since. Not only do they sound amazing, but the lines of interchangeable capsules and acoustic equalizers also make them extremely flexible tools. And quality? Durability? If they are good enough for NASA to employ in outer space, no doubt they will work well for you. Order yours today from your Sweetwater Sales Engineer at (800) 222-4700 and hear what a difference DPA mics can make in the sound of your recordings right here on Earth.
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