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Mars2020 landing cameras
Gerald
post Aug 28 2016, 12:34 PM
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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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rlorenz
post Oct 12 2016, 05:33 PM
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QUOTE (Gerald @ Aug 28 2016, 07:34 AM) *
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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pioneer
post Sep 18 2020, 12:42 AM
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I know this is an old thread, but I was wondering if the video from the EDL cameras will be compressed before being sent to Earth like the first images from Curiosity's MARDI camera were compressed as the bandwidth was limited in the early days after landing. Does anyone know if Mars Odyssey and MRO will be in position to receive signals from Perseverance on landing day?
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mcaplinger
post Sep 19 2020, 10:54 PM
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QUOTE (pioneer @ Sep 17 2020, 04:42 PM) *
Does anyone know if Mars Odyssey and MRO will be in position to receive signals from Perseverance on landing day?

Regardless of phasing, there are typically two passes per day per orbiter (see https://trs.jpl.nasa.gov/handle/2014/44382 ) and MAVEN and perhaps TGO will also be available, but there's usually some uncertainty about the performance of early relay ops.

From the April 2020 MRO status for MEPAG https://mepag.jpl.nasa.gov/meeting/2020-04/...202020_post.pdf
QUOTE
Cover mission critical events at Mars: Mars 2020 EDL in 2021

As for data return from the EDL cameras, that will probably be discussed in the pre-landing press kit and press conference.


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Disclaimer: This post is based on public information only. Any opinions are my own.
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pioneer
post Sep 20 2020, 06:56 PM
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QUOTE (mcaplinger @ Sep 19 2020, 11:54 PM) *
Regardless of phasing, there are typically two passes per day per orbiter (see https://trs.jpl.nasa.gov/handle/2014/44382 ) and MAVEN and perhaps TGO will also be available, but there's usually some uncertainty about the performance of early relay ops.

From the April 2020 MRO status for MEPAG https://mepag.jpl.nasa.gov/meeting/2020-04/...202020_post.pdf

As for data return from the EDL cameras, that will probably be discussed in the pre-landing press kit and press conference.


Thanks.
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mcaplinger
post Dec 10 2020, 03:30 AM
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A paper describing the engineering cameras on M2020, including the EDL cameras and the TRN camera, is now online at https://link.springer.com/article/10.1007/s11214-020-00765-9 (open access). Enjoy.


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Brian Swift
post Dec 10 2020, 05:58 AM
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QUOTE (mcaplinger @ Dec 9 2020, 07:30 PM) *
A paper describing the engineering cameras on M2020, including the EDL cameras and the TRN camera, is now online at https://link.springer.com/article/10.1007/s11214-020-00765-9 (open access). Enjoy.
Thanks. Nice to see it will have microphones (obviously I haven't been paying enough attention).
Playing with the OSIRIS-REx sample collection images, I was wishing it had a microphone (I'm assuming a mic mounted to the hull would pick up debris impacts).
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Steve G
post Dec 10 2020, 03:32 PM
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Thanks. That was a really good read.
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mcaplinger
post Dec 10 2020, 04:29 PM
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QUOTE (Steve G @ Dec 10 2020, 07:32 AM) *
That was a really good read.

We weren't that happy with it, since it's a whole lot of different stuff roughly stitched together and sort of veers between topics. But it didn't make sense to write separate papers either and it gets the basics across.

You'll note that the Gopros considered originally didn't make the cut, but I know nothing about what the story is with that -- all I worked on was LCAM.


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Phil Stooke
post Dec 10 2020, 08:55 PM
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In answer to a question posed above about EDL data relay: MRO looks like it will be doing this.

MRO: Providing radar 3D subsurface mapping of ice deposits and imagery and spectroscopy
of surface features and weather; also supporting landing site assessments. Developing “Bent
Pipe Communications” in support of Mars 2020 landing. Will continue to serve as major relay
asset for surface missions (Curiosity, InSight, Perseverance, ExoMars).

This is from this recent report:

https://www.lpi.usra.edu/pac/presentations/...0PACNov2020.pdf

Phil


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Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
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Tom O'Reilly
post Feb 17 2021, 06:11 AM
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QUOTE (mcaplinger @ Dec 9 2020, 07:30 PM) *
A paper describing the engineering cameras on M2020, including the EDL cameras and the TRN camera, is now online at https://link.springer.com/article/10.1007/s11214-020-00765-9 (open access). Enjoy.

Thanks Mike - great paper!
And lo and behold - there are two USB3 hubs on the EDLCAM system; one on the aeroshell and one in the descent stage (Figure 28)

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Tom O'Reilly
post Feb 17 2021, 06:16 AM
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QUOTE (Phil Stooke @ Dec 10 2020, 12:55 PM) *
In answer to a question posed above about EDL data relay: MRO looks like it will be doing this.

MRO: Providing radar 3D subsurface mapping of ice deposits and imagery and spectroscopy
of surface features and weather; also supporting landing site assessments. Developing “Bent
Pipe Communications” in support of Mars 2020 landing. Will continue to serve as major relay
asset for surface missions (Curiosity, InSight, Perseverance, ExoMars).

This is from this recent report:

https://www.lpi.usra.edu/pac/presentations/...0PACNov2020.pdf

Phil

Also this: https://www.jpl.nasa.gov/news/the-mars-rela...rtian-explorers
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Tom Tamlyn
post Feb 17 2021, 07:25 PM
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Fascinating Wired article about Jason Achilles Mezilis, a rock musician and space enthusiast who successfully pitched to be hired as a consultant for the Perseverance microphone team. https://www.wired.com/story/musician-who-de...icrophone-mars/

Mezilis was recently selected as PI for an imaging system for moon landers, the Lunar ExoCam project. https://www.space.com/lunar-exocam-landing-...eo-moon-surface.

Note for Mods: Previous discussion of Perseverance microphones is distributed among several existing threads, including this one. I chose this one because one of the microphones is designed to record EDL. There is a Tech, General and Imagery subforum for the MER mission.You might at some point consider setting up something similar for the Perseverance science and engineering instruments, so that information doesn’t get lost in what we hope will be a long series of narrative threads.

This post has been edited by Tom Tamlyn: Feb 17 2021, 08:02 PM
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deedan06
post Sep 8 2023, 01:20 PM
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Sorry if you guys already know this, but the EDL-Cams are actually still alive! The Rover Down look Camera seems to act as a MARDI succesor, however it takes images during drives. I Have no clue how they manage to transmit over 900 images on one day, probably using video compression. The capability to act fully independent seems to allow them to image while driving. The Rover uplook camera is also still alive and seems to act as skycams pal. I can't see much on the raw images, but if you edit the images togather you probably get better results. The Lander Vison system Camera shows no signs of activity however. The cameras seem to be reactivated around sol 700.

You can look at their images at the row images site, however you have to activate the "show movie frames" box for most of them to show up. If you have a very good internet connection I can also reccomend using this (https://areobrowser.com/#/mode=perseverance&instruments=ED) site to gat an overview and see rough video versions of the imagery. The Sol dates seem to only indicate the date of transmission and not when the images where taken, which is especially noticable for the RDC.

I have found no NASA statement on the surprisingly long live of the cameras although I haven't looked very hard. Once again sorry If I just repeat old info.
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