Leonard David reports that "the Phoenix lander team is going forward with turning on the spacecraft’s microphone."

I'm working on finding out more details. (For instance, I want to know if this also means they'll get to use the camera itself, maybe get a different perspective on Holy Cow, if the camera's pointing the right way.) In the meantime, enjoy hearing what Bill Nye and others would sound like on Mars before they asphyxiated.

Yay!

Emily

That's fantastic news! Being able to play kids the sound of the wind blowing on Mars would be brilliant! As you so eloquently put it, "Yay!"

Having said that... and without wanting to blow on anyone's chips here ... is this a sign that the Phoenix team is maybe sensing that the sand is really rushing through the hourglass now, and the time has come to start trying cool and unusual things..?

It's probably the realization that at this point, turning MARDI on can't jeopardize the success of the mission anymore so they might as well do it. I don't see it as running against the clock. I'm glad they decided to turn it on, was hoping it would happen sometime during the extended mission.

I wonder if it will be sensitive enough to hear wind directly? Maybe some cavity somewhere on Phoenix will resonate in the wind and make a whistle or hum? Maybe the sound of the solar arrays flapping in the wind would be easier to hear, if it could carry directly through the body of Phoenix?

It's hard to know what, if anything, it'll hear; it was intended to listen to descent noises (whoosh and all that), so is probably pretty insensitive to the level of sound that currently prevails at the landing site -- but we'll see. We also have to see if it still works or not. So -- hope, but don't expect, to hear anything!

--Emily

It would be great if they could acquire audio during soil sampling and ice scraping.

The motors in the robotic arm should produce a buzzing sound when operated, right?

OK, here's a challenge for someone(s) with a facility for 3D visualization. The question is, what would MARDI be looking at if it took an image right now? More specifically, could it see any of the ice patches in Holy Cow? Attached is an image of the underside of the lander, in which you can see MARDI (it's the thing covered with a blue cover, actually a glove, just like the glove the technician is wearing!) I've tried to puzzle it out but am afraid of errors and am hoping a couple of people here can try to figure it out independently. Also relevant: its FOV is 66 degrees.

--Emily

Perhaps we'll hear this...
Click to view attachment

Sorry...couldn't resist.

OK - If Phoenix is like a clock...

Solar Panels are at 2.30 and 8.30
The arm is mounted at about 1.30
MARDI looks to be at about 7 - sort of behind where the elbow of the arm was when folded flat.

http://www.lockheedmartin.com/data/assets/14819.gif
http://www.lockheedmartin.com/data/assets/14845.jpg

I would GUESS - the area marked green...possibly getting a corner of one bit of the exposed stuff - but with MARDI being pointing slight away from straight down, I'm not confident.

doug,


In the second image you posted above ( http://www.lockheedmartin.com/data/assets/14845.jpg) it appears the telltale 'cord' has the bend (or similar) that we have seen from the first Sol it was deployed....

cheers

Doug - I had thought that MARDI was fixed-focus (probably at Infinity) - so anything a few feet away would be out-of-focus, no?

You would think that, but actually it does pretty well at short distances. See the bottom of this blog entry.

--Emily

Thanks - I had missed that BLOG entry.

Mardi has an excellent depth of field.

FWIW, MARDI is just about exactly behind the met mast as seen from the SSI, and it's pointed 22 degrees outward from nadir.

If the camera's 22 degrees pointing out, and slightly away, to the west, from the nearest jet, then I don't think MARDI can see the HolyCow plume effect. I make the centerline of the camera about 18 inches from the nearest jet in the science deck plane (I think X/Y). The camera is below the deck some 5 inches, and that's about 3 feet (?) from the surface. A little trig tells me they'll miss it by half a foot, guessing the size of each "skating rink" to be maybe a foot and a half in diameter(??)

That's back of the envelope, so it's just a guess.

OK, I've got more details for all of you! Enjoy.

--Emily

Round up a bit. 66 deg FOV, 22 deg out-from-Nadir pointing.

That means 22 degrees of FOV inside of Nadir from the camera, and 44 degrees outside of Nadir.

Assuming a height of, say, 100 cm...

I make it 40cm of terrain inside a point directly under MARDI and 96 cm of terrain outside it ( Tan Theta = Opposite (the distance on the ground) over Adjacent ( the height of Mardi above the ground ) )

Now that we "know" where Mardi is, can we determine the mike position relative to the incoming (main) wind and weather it'll pick up the wind strait or be shadowed by Mardi itself?

The microphone is more or less omnidirectional, and pointed in the same direction as the optics. You can see it in photos of the instrument; for example http://www.msss.com/phoenix/mardi/illustra.../phx_mardi2.jpg (you probably knew this already.)

I don't know where the prevailing wind is from.

Now...wouldn't it be great to capture another DD sequence with a wooooosh as soundtrack?...

I think your arithmetic is wrong. The centerline of the camera is moved out 22 degrees. So straight down you get 33 degrees inside and outside of nadir. When you move the centerline out, it's 33 - 22 degrees inside of nadir.

It would be really cool to hear Phoenix digging Mars soli!
I stay tuned for news... Pleas keep us informed!

Glad to see the Swiss Military were part of the MARDI team.

When can we expect science return?

There was a small comment about when the microphone might be turned on in this news release.


It sounds as if this experiment has a rather low priority. Is that because the event might trigger a fault?

Could they be planning to turn the microphone on only after there is insufficient power for digging? I was hoping to hear the sounds of Phoenix scrapping the surface of Mars. I suppose the next most interesting sound would be the solar panels creaking in the wind.

SSI and MECA-OM are noisy.

I don't think the microphone is being deliberately delayed. It is just not the highest priority thing to work on--using equipment in a "new" way after months of thermal cycles is something that needs to be approached with care. There is special concern during RA use. That's not to say it won't happen, but I'd be surprised if it happened first.

Does anyone know where the SSI exposure times might be tabulated? I need them to compute some exposure times for another instrument on the surface that may be operated soon

Like this?



From Texas A&M University Surface Stereo Imager Vital Statistics

From Texas A&M University Phoenix Surface Stereo Imager (SSI)

No, like what exposure time a specific image was taken with.

Exposure information can be found in the header for all the JPEG images. Attached is a .csv file (zipped) with the metadata from all the JPEGs available to date, stripped from the headers using Midnight Mars Browser.

--Emily

Thanks for the CSV file! Apparently very few extent JPEG viewers can read the EXIF tags for some reason.

Hmm. If I want to see a header, usually I just open the JPEG file in a text editor. --Emily

Irfanview works a treat. Just hit the 'image information' button or press 'i' and hit hit the 'comment' button or press 'c'.

But seriously, when is the microphone going to be activated?

The recordings of Martian sounds would make a dramatic backdrop for every image of Mars ever captured.

I'd hate to have the only sound sent to Earth be a 5-second clip of a solar panel snapping off from frost.
[/vent]

Let me try to lower your expectations. The audio is only digitized at 8 KHz (telephone quality at best), so even if it does work, IMHO it's not going to "make a dramatic backdrop" to anything.

Please say it's not 8 bits/sample!

It's not 8 bits/sample

(you said please)

If it's roughly the same as the '98 one, the ADC is 12bit.

Prepare to be unamazed by the quality. http://www.planetary.org/programs/projects...microphone.html

I am indeed unamazed, but at least the sample depth is 12 bit. 8 bits is pretty much useless and very noisy for any appreciable dynamic range.

It's got nothing in common with the Planetary Society microphone, but it's not 8 bits.

"DSP561xx processors are noteworthy because they include a sigma-delta codec on-chip. The sigma-delta codec provides linear, analog I/O with 16-bit resolution over a bandwidth of approximately 4 kHz. Motorola states that the codec has a signal to noise-plus-distortion ratio of greater than 60 dB. "

As always with ADCs, though, caveat emptor about how many of the stated bits are actually significant...



Indeed.

Well, I wouldn't say that we exactly need high-fidelity surround-sound here! Do we expect much Martian sound above 8 kHz? Obviously higher signal-to-noise improves our chances of hearing anything at all, but I for one would be thrilled to hear even a sub-telephone-quality recording of the creaking of the solar panels flexing in the wind.

Sneak preview of the first sounds to be recorded by the mic...

http://www.popularmechanics.com/science/ai....html?series=60

Smith talks about using the microphone.

From the BBC:

Bang a few pots....I like it.

I really hope that they get the microphone up and running before Phoenix kicks the bucket. Even just a few minutes of hearing the whisper of the Martian winds would be pretty cool.

Thanks, fredk. I enjoyed that article. This lander's mission was really quite complicated, was it not? Since Phoenix is not a rover, it was interesting to see how the team assigned priorities. Organics, isotopes, ions, and whatever else they hoped to find, this has been a really fascinating planetary adventure. I want to see another one. Hearing something will be fun, but it's not the highest priority on my agenda. I am fully prepared to begin banging pots at any time, if that is required.

Does anyone know if they ever got a chance to use the microphone? Also, is it still being considered (although banging with the arm is obviously out of the question?). It seems that when they are back up and running, while the most obvious source of noise is gone, it might be worth giving it a go now (in other words, they don't have nearly as much to lose considering so many of the instruments are out of operation).

The Twitter feed (October 29) gave an indication or two that it might be tried before too long, but then the storm hit.



If they had done it I think it would have been reported on Twitter or a news release.