Mars2020 landing cameras |
Mars2020 landing cameras |
Jun 15 2016, 10:19 PM
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#16
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Junior Member Group: Members Posts: 22 Joined: 7-January 13 Member No.: 6834 |
I am so enthusiastic about the (proposed) Mars2020 camera suite during EDL, as presented today at IPPW:
- 3 PointGrey Chameleon 3 that will be on the skycrane and look up, to monitor parachute deployment at 150 fps. - 1 GoPro Hero 4 on the skycrane, looking down to monitor the rover descent and landing - 1 GoPro Hero 4 on the rover, looking up to monitor the skycrane and fly-away - 1 GoPro Hero 4 on the rover, looking down like MARDI did on Curiosity - MARDI, of course. All GoPro have microphone that will be activated, and have been tested successfully in the proper thermal and radiative environment. We should have some awsome footage if it actually flies. |
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Aug 28 2016, 12:34 PM
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#17
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
I don't think, that sound attenuation poses any significant issue on Mars on the meter scale, especially when relative humidity is very low.
With this calclulator for atmospheric absorption, for sound of 1000 Hz, I get 0.014 dB / m for 103 kPa at 0°C with 10% relative humidity, and 0.0255 dB / m for 0.6 kPa at -20°C with 1% relative humidity. Above 10 kHz, it may be going to become an issue on the meter scale. The microphone membrane, however, might be required to deal with reduced sound intensity, since the low-pressure atmosphere transports less sound energy for the same amplitude. |
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Oct 12 2016, 05:33 PM
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#18
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Member Group: Members Posts: 613 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
I don't think, that sound attenuation poses any significant issue on Mars on the meter scale, The microphone membrane, however, might be required to deal with reduced since the low-pressure atmosphere transports less sound energy for the same amplitude. Yes, 6mb CO2 conveys sound quite happily over distances of a few meters. Here is some music played ('quite loud' in 1 bar air, but considerably quieter here at 6mb simply because a loudspeaker diaphragm displacement at a given speed produces a lower sound pressure level simply because the air density is lower, as you note). The sound is a bit distorted (ethereal, dare I say..?) because of reverberation/multipath between the parallel metal walls of the chamber (these were tests I did a couple of weeks ago at the Mars Environment simulation chamber in Aarhus, Denmark). There's also a lot of plant noise (electrical, rather than vibration/acoustic) http://www.lpl.arizona.edu/~rlorenz/oxygene_on_Mars.mp3 More details to be presented at the Mars Atmosphere workshop in Granada in January Ralph Lorenz |
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