Something on a NASA photo from Mars [Cosmic Ray]

Rory

Senior Member.
[UPDATE: According to Justin Maki, the engineering camera lead for the Mars Science Laboratory, the dark mark is the result of a cosmic ray]


Email from Justin Maki, forwarded to me by Linda Kah. Justin is the engineering camera lead for the Mars Science Laboratory mission and a member of the MSL Science Camera Team.


Hi Linda –

That is a textbook cosmic ray!

In this particular case the cosmic ray appears dark rather than bright because the cosmic ray hit the detector during a bias (shutter) frame acquisition. The shutter image is subtracted from the image of interest, producing a low pixel DN (digital number) value, i.e., a dark smudge.

Note that dark smudges are also sometimes due to physical debris on the detector (e.g., WATSON and MAHLI). But in this particular case it is definitely a cosmic ray.

Cosmic rays come in all sort of styles – most of them are due to protons, i.e., ionized hydrogen. The length and shape of the cosmic ray streaks depend on the angle at which the cosmic ray hits the detector. Cosmic rays are fascinating btw.

Cosmic ray hits are actually pretty common – most go unnoticed, unless they appear in the sky.

Examples attached, and links below:
Cosmic ray examples (mostly nighttime images):

https://photojournal.jpl.nasa.gov/catalog/PIA05551
https://photojournal.jpl.nasa.gov/catalog/pia06337
https://www.space.com/mars-insight-meteor-photographs-cosmic-rays.html

Hope this helps!
Content from External Source

Original first post follow
-----------------------------------------------------------------------------------------------------------------------------------------------------------------

Hello community of meteorologists, pilots, scientists and other sky-watchers -

Here's a NASA photo from October 5th (Sol 3613) taken by the right navigation camera of the Curiosity rover:

_mars.nasa.gov_msl-raw-images_proj_msl_redops_ods_surface_sol_03613_opgs_edr_ncam_NRB_71823098...JPG
Source: https://mars.nasa.gov/raw_images/1126107/

As we can see, there's a little something in the upper left.

First guess might be a blemish on the lens - though to counter that it's not there in other photos from that day or the day before, including one taken twelve seconds later:

https___mars.nasa.gov_msl-raw-images_proj_msl_redops_ods_surface_sol_03613_opgs_edr_ncam_NRB_7...JPG

Unfortunately the preceding photo was taken over 20 hours earlier and doesn't show anything useful (this one here).

Gallery for that camera on Sol 3613 here (other cameras don't help as far as I can tell):

https://mars.nasa.gov/msl/multimedia/raw-images/?order=sol+asc,instrument_sort+desc,sample_type_sort+desc,+date_taken+asc&per_page=50&page=0&mission=msl&begin_sol=3613&end_sol=3613&af=NAV_RIGHT_A|NAV_RIGHT_B,,,
 
Last edited by a moderator:

FatPhil

Senior Member.
Weird one. It seems to have 2 parts to it.

The left end is a few pixels with an unfeasably high contrast ratio with neighbouring pixels, which doesn't conform to the CoC of anywhere else in the image (which presumably is intended to all be decently in focus), which makes me think it's a digital sensor/data issue. I notice that even the *noise* is ringing in the image - that sensor is clearly struggling to extract an image (notice that darker pixels are consistently followed by lighter ones across the whole field, I can't see how that can be explained as diffraction/PSF, that's more like ringing/ghosting, an analogue comms phenomenon). What is the tech of the camera system, does anyone know?

The right end smear has enough blurring to be explained by the CoC seen in the rest of the image, and thus be something in the optical realm. There's no reason why surface matter can't be occasionally whipped up by the winds, but an isolated piece seems a bit unlikely.
 

FatPhil

Senior Member.
Could be a cosmic ray? I have seen similar artifacts on Mars photos before. The size and shape depends on the angle at which the particle hits the camera sensor.

Edit: although the one I was thinking of appeared as a light streak, rather than a dark one. https://descrier.co.uk/science/nasa-explains-mysterious-light-surface-mars-shown-rover-pictures/

Cosmic rays should be off-the-scale positive signals, so white, yup - but is this possibly temporary *blindness* as an aftereffect of the cosmic ray?
 

Mick West

Administrator
Staff member
Looks like the normal exposure time from the MastCams are 1000 ms in daytime.
That (1 second) appears to be referring to a dark calibration exposure. Later they say:

The amount of smear signal in a given image is proportional to the ratio of the frame readout time to the exposure time. For example, for typical Mastcam exposure times of 10 ms

10 ms is 1/100th of a second
 

deirdre

Senior Member.
Looks like the normal exposure time from the MastCams are 1000 ms in daytime.
disclaimer: taken from a 2003 manual..so may not be true

is that the same as
Article:
Optics
The Navcams have f/12 cameras with a 14.67 mm focal length. They have a 45 x 45 degree field of view, with a 67 degree diagonal. They have an angular resolution at the center of the field of view of .82 mrad/pixel. The field depth of the Navcams ranges from .5 meters to infinity. The nominal exposure time for a noontime image on Mars is approximately .25 seconds. This time is 50 times the frame transfer time of 5.1 ms. This ensures that the image signal is significantly than the image smear acquired during the frame transfer.
 
Last edited:

Ann K

Senior Member.
Private communication from Dr. Linda C Kah
The far left side is clearly a bad point on the detector. Probably just optic spear from that.
Content from External Source
It's been there for a decade, so my expectation is that such glitches might become more frequent.
 

johne1618

Active Member
Right Navigation Camera (no left camera data)

Sol 2446 19-6-24 08:35:52 UTC

1.jpg

Sol 2446 19-6-24 08:36:05 UTC

2.jpg

Sol 2446 19-6-24 08:36:18 UTC

3.jpg

Blow-up of object in Sol 2446 19-6-24 08:36:05 UTC

2446.jpg

If the exposure time is 0.25 secs then it must be a very slow glitch!
 
Last edited:

AmberRobot

Active Member
Private communication from Dr. Linda C Kah
The far left side is clearly a bad point on the detector. Probably just optic spear from that.
Content from External Source
It's been there for a decade, so my expectation is that such glitches might become more frequent.
Bad pixels tend to persist, so wouldn’t it show in other images from the same sensor? Though they are typically corrected during image processing. Maybe one was acting up beyond its normal behavior and slipped through? Does anyone know what “optic spear” means? Haven’t heard that one before.
 

Ravi

Senior Member.
disclaimer: taken from a 2003 manual..so may not be true

is that the same as
Article:
Optics
The Navcams have f/12 cameras with a 14.67 mm focal length. They have a 45 x 45 degree field of view, with a 67 degree diagonal. They have an angular resolution at the center of the field of view of .82 mrad/pixel. The field depth of the Navcams ranges from .5 meters to infinity. The nominal exposure time for a noontime image on Mars is approximately .25 seconds. This time is 50 times the frame transfer time of 5.1 ms. This ensures that the image signal is significantly than the image smear acquired during the frame transfer.

250ms exposure.
That would mean that a moving object in the Martian sky would be (motion) blurry, right? Not so much seen on the black dotted images above. I think it is caused by cosmic rays temporary "blinding" the pixels (Mars does not have a magnetosphere to deflect charged particles). Perhaps a static issue.
 

AmberRobot

Active Member
I would assume cosmic rays would produce bright not dark pixels (what I’ve always seen) but depending on the processing being done perhaps something was oversubtracted (seems unlikely to me but not impossible).
 

Mick West

Administrator
Staff member
Private communication from Dr. Linda C Kah
The far left side is clearly a bad point on the detector. Probably just optic spear [smear?] from that.
Content from External Source
It's been there for a decade, so my expectation is that such glitches might become more frequent.
So, it being "clearly a bad point on the detector" is because there's some perfectly black pixels with no aliasing. On the left.

2022-10-24_13-59-09.jpg

As to why it's smeared (if that's what it is) I'd defer to an expert. But a couple of maybe clues:

Article:
Each Navcam uses a 1024 x 2048 pixel CCD with 12 micron-square pixels and a 100% optical fill factor. The CCDs operate in frame- transfer mode, dividing the detector into two regions. One of the regions is a 1024 x 1024 pixel photosensitive imaging region where the image is recorded. The other region is a 1024 x 1024 shielded storage region where the recorded image is shifted and stored during detector readout. It takes 5.1 msec to transfer data from the imaging region to the storage region, and 5.4 seconds for readout of data from the storage region. Each CCD includes 32 non-imaging pixels in the serial readout registers, which allow the monitoring of the CCD electronics offset and detector noise performance. The Navcam CCD pixels have full well capacities of approximately 170,000 electrons and are digitized at 12 bits/ pixel. The RMS read noise at cold temperatures (-55 degrees C) is approximately 20 electrons, and the detector system has gain values of approximately 50 e-/DN, which results in a system with approximately 0.5 DN of RMS read noise.
...
The Navcam CCDs use a 'clocked antiblooming' readout technique, instead of having anti-blooming circuitry.


I really don't know, but somewhere in the combination of recording and readout (with antibloom ) a transient glitch might affect subsequent pixels, and (somehow) subsequent rows.

Which would suggest the error/glitch/spike/cosmic ray is in the readout circuit, not the sensor array.
 
Last edited:

Mick West

Administrator
Staff member
Private communication from Dr. Linda C Kah
The far left side is clearly a bad point on the detector. Probably just optic spear from that.
Content from External Source
It's been there for a decade, so my expectation is that such glitches might become more frequent.
Could you ask her how you get a black optic smear?
 

Rory

Senior Member.
A couple more for reference:

NRB_614635188EDR_S0760988NCAM00595M_.jpeg
Taken Sol 2446 (24th June, 2019 08:36:05Z) also with the right navigation camera (images taken 13 seconds before and 13 seconds after show nothing).

NRB_458574869EDR_F0390444NCAM00295M_.jpeg
Sol 688 (14th July, 2014 02:06:13Z) - same camera again.

Fortunately, the left navigation camera also took an image of the same view at that exact same moment and we can see that there's no 'object' in the scene. Therefore I believe we have good evidence that the right navigation camera is glitching.

NLB_458574869EDR_F0390444NCAM00295M_.jpeg

Sources: Top | Middle | Bottom

ADD: Oh wait - that's the exact conclusion that was reached TWO YEARS AGO in the thread linked by Mick above - and apparently six years ago elsewhere:

The two images are of the same scene in the same second, suggesting that the speck is a glitch in the right camera. This left/right difference was noticed on the "whatisupinthesky" forum,nearly 4 years ago.

https://www.metabunk.org/threads/mars-black-speck-ufo-sol-688-glitch.11424/
 
Last edited:

FatPhil

Senior Member.
Could you ask her how you get a black optic smear?
Indeed - is it possible that it could have been a cascade of slightly lower energy particles from an initial high-energy colision? There's presumably no field to cause any curved tracks, so the effect is just lightly scattered. We probably need a physicist or a sensor expert. I'm sure this has to be something that they test for resilience against, as it seems to be quite a common occurence - were it to have permanent consequences they'd need to know, and defend against, so this surely must have been deemed an acceptable temporary glitch.
 

deirdre

Senior Member.
were it to have permanent consequences they'd need to know, and defend against, so this surely must have been deemed an acceptable temporary glitch.
they just end up a new rover every few years. we love spending money on excess doodads (besides if nothing goes "wrong" with the old model you cant get funding for new stuff) :)
 

Ann K

Senior Member.
they just end up a new rover every few years. we love spending money on excess doodads (besides if nothing goes "wrong" with the old model you cant get funding for new stuff) :)
Its expected lifetime was five or six years.
 

jackfrostvc

Senior Member
Private communication from Dr. Linda C Kah
The far left side is clearly a bad point on the detector. Probably just optic spear from that.
Content from External Source
It's been there for a decade, so my expectation is that such glitches might become more frequent.

Can I ask who Dr. Linda Kah is?
Is she part of the mars mission
 

deirdre

Senior Member.
Can I ask who Dr. Linda Kah is?
Is she part of the mars mission
Article:
Kah, an associate professor of geology at the University of Tennessee Knoxville, studies some of the oldest life on Earth. Now she is bringing that expertise to Mars for the second time.

As a co-investigator for the NASA Mars Mission, Kah is trying to find evidence of water and potentially life to bring back to Earth.
 

AmberRobot

Active Member
I have some experience with science grade CCDs and all cosmic rays I’ve ever seen produce electrons and thus would result in a positive signal (I.e., they’d look white not black). A bad pixel tends to stay bad so all image should show it, and they are often corrected in processing.

The CCd architecture is such that it reads Columns into a serial register and then reads it out row by row. A frame transfer CCd quickly shuffles charge into a covered region to be read out and not accumulate any additional exposure. I would expect artifacts from frame transfer to be along columns.

Anti-blooming tends to relate to pixels that have bright sources imaged onto them such that they produce more electrons than full well. These then can bleed into neighboring pixels (often more along columns than rows) so it is doubtful that is what is at play here.

I know some folks at JPL so I can see if I can track someone down who may know what’s up here.
 

Ann K

Senior Member.
Can I ask who Dr. Linda Kah is?
Is she part of the mars mission
She is a geologist and a member of the science team. She has been involved since the design phase of Curiosity (years before it was built and launched) as it was sent to examine the geology ("areology"?) of Mars, and all the instrumentation is intended to sample the surface rocks, drill small cores, determine the chemistry, etc. She was involved in choosing the landing site as a place of geologic interest. She is similarly actively involved with the successor rover, Perseverance.

The science team decides, and the "Martians" (rocket scientists) at JPL are involved with building and sending the spacecraft. The photography specialists and instrument engineers are just some of the contributing groups. Essentially, the Martians' work was done when the rover landed, and the scientists' work was just beginning.

Full disclosure: she is also my daughter.
 

NoParty

Senior Member.
She is a geologist and a member of the science team. She has been involved since the design phase of Curiosity (years before it was built and launched) as it was sent to examine the geology ("areology"?) of Mars, and all the instrumentation is intended to sample the surface rocks, drill small cores, determine the chemistry, etc. She was involved in choosing the landing site as a place of geologic interest. She is similarly actively involved with the successor rover, Perseverance.

The science team decides, and the "Martians" (rocket scientists) at JPL are involved with building and sending the spacecraft. The photography specialists and instrument engineers are just some of the contributing groups. Essentially, the Martians' work was done when the rover landed, and the scientists' work was just beginning.

Full disclosure: she is also my daughter.
So, you don't have any other offspring on the Mars Team? A photo expert, maybe? :p Love this!
 

AmberRobot

Active Member
She is a geologist and a member of the science team. She has been involved since the design phase of Curiosity (years before it was built and launched) as it was sent to examine the geology ("areology"?) of Mars, and all the instrumentation is intended to sample the surface rocks, drill small cores, determine the chemistry, etc. She was involved in choosing the landing site as a place of geologic interest. She is similarly actively involved with the successor rover, Perseverance.

The science team decides, and the "Martians" (rocket scientists) at JPL are involved with building and sending the spacecraft. The photography specialists and instrument engineers are just some of the contributing groups. Essentially, the Martians' work was done when the rover landed, and the scientists' work was just beginning.

Full disclosure: she is also my daughter.
You should be proud of your daughter and the great work she is doing.

That being said, my experience is that members of a mission’s science team don’t necessarily have any expertise in the design, calibration, or operation of the instruments that provide the science data to them.
 

Ann K

Senior Member.
That being said, my experience is that members of a mission’s science team don’t necessarily have any expertise in the design, calibration, or operation of the instruments that provide the science data to them.
That's why I suggested the camera people should be consulted. :)
 

AmberRobot

Active Member
Ok.. I got some feedback from someone I know at JPL. Here's what is most likely happening. These cameras are frame transfer CCDs used without a mechanical shutter. They operate using what is called an "electronic shutter". As part of the readout process, they read what is called a "bias frame", essentially a zero second exposure that is subtracted from the main image to remove certain kinds of effects, like fixed pattern noise generated by the amplifiers. When a cosmic ray hits during the readout of the bias frame, it will create a bright spot on the bias frame, which is then subtracted from the main image, created a dark feature in the main image. It's like a shadow of the cosmic ray that hit.

I was told that cosmic ray hits are relatively common, but usually go unnoticed, unless they appear in the sky, like this one did. If the cosmic ray hits in the main image and not the bias frame then they'll show up as bright.

Here's a paper about the cameras:
"Mars Exploration Rover Engineering Cameras", Maki et al. Journal of Geophysical Research 108, E12, 8071 (2003)

Check out section 3.1.12 for a description of this process. The link wouldn't let me cut and paste here.
 
Top