Perseverance EDL, 18 Feb 2021 Options

[MahFL]

Does anyone know if the springs on the heat shield are supposed to be captured or not ?

[Greenish]

...I am aware of the raw image site API quick "hack" to pull up a partial JSON list, but it seems to be very limited. Any other ways to bulk download, I'm also all ears.

Assume you've already tried this, and I'm learning as I go here. The default one limits to 50-images per page. But by messing with that query you can get a huge file with all images and their data (at least for a given sol), including direct filename links, pointing data, subframe, etc...You're looking for something else?

For Perseverence, "https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&sol=0&order=sol+desc&&&extended=" gets at present a 6.5MB file with details for the 3559 sol 0 images there right now.

For example on sol 2 one "full res" link is "https://mars.nasa.gov/mars2020-raw-images/pub/ods/surface/sol/00002/ids/edr/browse/rcam/RRB_0002_0667129492_604ECM_N0010052AUT_04096_00_2I3J01.png")

There are other fields too. If you know an image filename you can go straight to the metadata for that image, e.g. "https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&id=RRB_0002_0667129492_604ECM_N0010052AUT_04096_00_2I3J01"

If I knew anything about web development I'd try to reformat and post it for general use somehow.

[stevesliva]

Does anyone know if the springs on the heat shield are supposed to be captured or not ?

Press conference said that the free spring was surprising, but not alarming. It sure is neat to watch, though.

[MarsInMyLifetime]

... If you know an image filename you can go straight to the metadata for that image, e.g. "https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&id=RRB_0002_0667129492_604ECM_N0010052AUT_04096_00_2I3J01"

If I knew anything about web development I'd try to reformat and post it for general use somehow.

That query is perfect for redisplaying from their site. I'm sure there are better ways, but your question piqued my interest. I got this far using PHP to decode a result from the API for display, say in a sidebar widget in WordPress (and maybe add a link to the large version, etc.).

CODE

$mfn = 'RRB_0002_0667129492_604ECM_N0010052AUT_04096_00_2I3J01';
$url = 'https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&id='.$mfn;
$data = file_get_contents($url); // put the endpoint result into a variable
$array = json_decode($data, TRUE); // turn JSON feed into array
var_dump($array); // see the array structure for the specific image path
$image_caption = $array['image'][0]['caption']; // slice out the caption
$image_small = $array['image'][0]['image_files']['small']; // slice out the small image path
echo $image_caption.'<br/><img src="'.$image_small.'">';

[erentar]

I have trouble downloading all the data in bulk. Can anyone point me to a trick? Is there another place to download the data with wget possibly?

I have a python script that write all links to a file, then you can use wget on that

CODE

import requests,json,math
per_page = 100
total_images = json.loads(requests.get("https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&num=0&page=0&order=sol+desc&&&extended=").text)["total_images"]
linksfile = open("jpl_raw_links.txt","a")

for i in range(math.ceil(total_images/per_page)):
    data = json.loads(requests.get("https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&num="+str(per_page)+"&page="+str(i)+"&order=sol+desc&&&extended=").text)
    for i in range(int(data["per_page"])):
        linksfile.write(data["images"][i]["image_files"]["full_res"]+"\n")
linksfile.close()
print("done")

[Mercure]

Regarding the parachute movies/images. They're from two different upward-pointing cameras so in principle it should be possible for our imaging wizards to do a 3D-version. Can't think of a better subject matter for a 3D movie.

[Greenish]

MarsInMyLifetime & erentar, so cool - I knew there were folks here with interest.

Note they do have a suggested way to embed images (in the sidebar of the individual image pages):

Embed this resource by pasting the following code into your website:
<iframe src="https://mars.nasa.gov/layout/embed/image/500raw/?i=NLM_0004_0667310972_991ECM_N0010052AUT_04096_00_2LLJ01" width="500" height="500" scrolling="no" frameborder="0"></iframe>
Image Use Policy

In order to keep this thread focused on EDL rather than data wrangling, may I suggest we reconvene on this thread in the Image Processing Techniques subforum... looks like phase4's Marslife 3D browser is already playing with Percy images and y'all speak the same language I suspect

(unless the MODS think we can/should start a dedicated Perseverence image processing thread, as happened for MSL, Juno, etc.)?

[MarT]

Regarding the parachute movies/images. They're from two different upward-pointing cameras so in principle it should be possible for our imaging wizards to do a 3D-version. Can't think of a better subject matter for a 3D movie.

I have already had a look at it. But the second cam has only a few images. Anyway, it will be possible, but it will make your eyes hurt. The tangles from the parachute are right in between the both cams, if I interpreted the image correctly.

Also thanks everyone for the help with the code!

[ugordan]

BTW, the documentary "Built for Mars: The Perseverance Rover" on NatGeo last night was excellent.

I really wish those of us outside the U.S. could also get to see these kinds of documentaries without this geo-lock stuff.

[xflare]

The MARDI camera on Curiosity captured the heatshield impacting the surface while still on the parachute.

https://www.youtube.com/watch?v=vVLPXfF3l_U

It looks like the impact site for Perseverance's heatshield moved out of view while on the parachute???

EDIT: Have rewatched the decent video and im pretty sure the impact site goes out of view now.

[charborob]

I was wondering at what moment exactly the upward-looking cameras on the backshell started recording images. Was it just before parachute deployment? Were they turned on during atmospheric entry and the peak heating phase? That might have been interesting.

[djellison]

Turned on just before chute deploy - but behind the cover that comes off at deployment, hence some black frames at the start of the sequence

[Hungry4info]

This raw image shows what I think we can much more confidently assert is the Skycrane crash plume. Marshall Eubanks on the Asteroid Explorer's Facebook posted a contrast-enhanced image showing the plume in more detail, which I've attached here.

Edit: there's two images showing the plume, posted here. Also attached.

Attached thumbnail(s)

 

[Explorer1]

Certainly seems so much larger than the Curiosity plume (though that is a much lower quality image). Great catch!

[atomoid]

I think there ever was only one frame of Curiosity's skycrane plume.
I'm not sure how many frames will come down for this one though, but hopefully a lot more, as it will be interesting to get a visceral sense of how the plume develops and decays within Mars' gravity and atmosphere.

Also quite surprising to me was the lack of any visible exhaust gas plume or heat refraction wavelet distortion emanating from the nozzles in the skycrane images as you would expect terrestrially, i guess it owes to the negligible atmospheric pressure being not enough to generate a refraction difference against the surrounding gasses perhaps. Video like this can really illustrate the otherworldliness of Mars so much better than anything else.