Author Topic: Perseverance/MARS2020 for developers  (Read 6712 times)

Offline spacexplorer

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Perseverance/MARS2020 for developers
« on: 03/08/2021 02:37 pm »
You are a developer and want to share your knowledge and technical tips about Perseverence missions?
Write them here!

For example: there is a REST API available to manually retrieve images data in JSON format:

https://api.nasa.gov/mars-photos/api/v1/rovers/curiosity/photos?sol=1000&camera=fhaz&api_key=DEMO_KEY

Official documentation? https://github.com/chrisccerami/mars-photo-api

Unofficial documentation: https://dev.to/meredydd/getting-photos-from-mars-with-the-nasa-api-3l2l

------------

Links to official EDL videos from onboard cameras:


Perseverance’s Descent & Touchdown on Mars: Descent Stage Down-Look Camera video:
https://www.you tube.com/watch?v=vusXJXMeX9k&list=UUryGec9PdUCLjpJW2mgCuLw&index=5

Perseverance’s Descent & Touchdown on Mars: Parachute Up-View Camera video:
https://www.you tube.com/watch?v=BsXFIbe-5y4&list=UUryGec9PdUCLjpJW2mgCuLw&index=6

Perseverance’s Descent & Touchdown on Mars: Parachute Deploy Slowed to 30% speed video:
https://www.you tube.com/watch?v=LdSSCLOqLag&list=UUryGec9PdUCLjpJW2mgCuLw&index=7

Perseverance’s Descent & Touchdown on Mars: Parachute Up-View Camera 2 video:
https://www.you tube.com/watch?v=ZbTJ_YCTDLI&list=UUryGec9PdUCLjpJW2mgCuLw&index=8

Perseverance’s Descent & Touchdown on Mars: Rover Descent Camera video:
https://www.yout ube.com/watch?v=L1taqzNovbk&list=UUryGec9PdUCLjpJW2mgCuLw&index=9

Perseverance’s Descent & Touchdown on Mars: Rover Up-Look Camera video:
https://www.yout ube.com/watch?v=uKxYMRfKAEs&list=UUryGec9PdUCLjpJW2mgCuLw&index=10


-----------

Found the exact time of the Tango Delta (wheels on ground) in this video.
If you enable "statistics for nerds", you can see seconds and milliseconds of current frame.
I identified these moments:

Rover separation: 04.700
Snatch: 09.350 (maximum bridles extent, rover oscillation starts)

Rover oscillation stops: 20.470 (first wheel contact) (+0.000, +0.000)
Last frame with intact bridle: 21.830 (+0.360, +0.260)
First frame with cut bridle: 22.160 (+1.690, +0.330)
Flyaway start: 22.630 (+2.160, +0.470)

So approximate/rounded times could be:
 - First contact: 20.500  (+0.000)
 - TD declared, bridle cut: 22.000  (+1.500)
 - Flyaway: 22.500 (+2.000)

For MSL, planned timing were:
 - First wheel contact: 0.000
 - (All wheels down: 1.700)
 - TD declared, bridle cut command: 2.700
 - Flyaway start: 3.187

Rounded to 0.5 secs:
 - First contact: 0.000
 - (All wheels down: 1.500)
 - TD declared, bridle cut: 2.500
 - Flyaway: 3.000

Hence this recorded timings for Perseverance can be considered approximately acceptable:

 - First contact: 20.500  (+0.000)
 - TD declared, bridle cut: 22.000  (+1.500)
 - Flyaway: 22.500 (+2.000)




Matched to timings of control room video:
(Event, rover up camera video timing, control room timing, delta w.r.t first contact)
 - First contact: 20.500  - 01:55:29.500  (+0.000)
 - TD declared, bridle cut: 22.000  - 01:55:31.000  (+1.500)
 - Flyaway: 22.500 - 01:55:31.500  (+2.000)
 - TD nominal - 27.000 - 01:55:36.000 (+6.500)
 - Rover up-camera video end: 28.000  - 01:55:37.000  (+7.500)
 - RIMU stable - 34.000 - 01:55:43.000 (+13.500)
 - UHF is good - 37.000 - 01:55:46.000 (+16.500)




« Last Edit: 03/11/2021 05:10 pm by spacexplorer »


Online Phil Stooke

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Re: Perseverance/MARS2020 for developers
« Reply #2 on: 03/09/2021 05:34 pm »
A word of warning about the position data and the map linked in the previous post.  If you zoom right in on the map you will see that the first location (labelled 'sol 2') is too close to the drifts behind the rover.  The correct location would be about 3 m southeast from there.  Whether the discrepancy is in the rover position or the base map registration is unclear - either will have the same effect.  But if you want to register them properly the entire traverse has to be shifted 3 m southeast, or the base map has to be shifted 3 m northwest.

Online Phil Stooke

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Re: Perseverance/MARS2020 for developers
« Reply #3 on: 03/09/2021 06:20 pm »
http://www.unmannedspaceflight.com/index.php?showtopic=8608&st=45&gopid=250804&#entry250804

This links to an illustration of the offset I mentioned above.

Offline spacexplorer

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Re: Perseverance/MARS2020 for developers
« Reply #4 on: 03/10/2021 07:11 am »
A word of warning about the position data and the map linked in the previous post.  If you zoom right in on the map you will see that the first location (labelled 'sol 2') is too close to the drifts behind the rover.  The correct location would be about 3 m southeast from there.  Whether the discrepancy is in the rover position or the base map registration is unclear - either will have the same effect.  But if you want to register them properly the entire traverse has to be shifted 3 m southeast, or the base map has to be shifted 3 m northwest.
Do you mean NASA is doing it wrong? In this forum such comments are not very appreciated.

Online Phil Stooke

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Re: Perseverance/MARS2020 for developers
« Reply #5 on: 03/10/2021 07:17 am »
No, it means the person doing the mapping has inadvertently allowed a 3 m offset between the base map and the mapped points.  I am not the only person who has noticed it.  They will correct it - but people using the data should be aware of it, including the good folks on this site.  Misregistrations like that are easy to make - you only have to look at Google Maps to see many examples of the road vector layer offset from the images, with no certainty about which is in the wrong place.

Offline spacexplorer

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Re: Perseverance/MARS2020 for developers
« Reply #6 on: 03/10/2021 07:46 am »
Filtering raw images by camera and sol (amateur site):
https://rkinnett.github.io/roverpics/?mars2020&sol0&filter=ELM


Based on JPL RSS official API:
https://mars.nasa.gov/rss/

Example URL:
https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&id=SI0_0018_0668555815_008ECM_N0030578SRLC08001_0000LUJ


Exploded:


 - https://mars.nasa.gov/rss/api/  Base address
 - ?  Query start
 - feed=raw_images  Select database of raw images
 - &category=mars2020  Select mission
 - &feedtype=json  Results returned in JSON format (for Javascript) rather than XML
 - &id=SI0_0018_0668555815_008ECM_N0030578SRLC08001_0000LUJ Specific image identifier


Another image query API; Perseverance is not yet present in documentation but it is documented on github:
https://api.nasa.gov/mars-photos/api/v1/rovers/perseverance/photos?sol=1&api_key=DEMO_KEY

Available cameras:

EDL_RUCAM   Rover Up-Look Camera
EDL_RDCAM   Rover Down-Look Camera
EDL_DDCAM   Descent Stage Down-Look Camera
EDL_PUCAM1   Parachute Up-Look Camera A
EDL_PUCAM2   Parachute Up-Look Camera B
NAVCAM_LEFT   Navigation Camera - Left
NAVCAM_RIGHT   Navigation Camera - Right
MCZ_RIGHT   Mast Camera Zoom - Right
MCZ_LEFT   Mast Camera Zoom - Left
FRONT_HAZCAM_LEFT_A   Front Hazard Avoidance Camera - Left
FRONT_HAZCAM_RIGHT_A   Front Hazard Avoidance Camera - Right
REAR_HAZCAM_LEFT   Rear Hazard Avoidance Camera - Left
REAR_HAZCAM_RIGHT   Rear Hazard Avoidance Camera - Right
SKYCAM   MEDA Skycam
SHERLOC_WATSON   SHERLOC WATSON Camera



It would be very interesting to be able to filter mastcam images by azimuth and elevation, but I can't understand if it is possible.
« Last Edit: 03/10/2021 07:54 am by spacexplorer »

Offline lvm

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Re: Perseverance/MARS2020 for developers
« Reply #7 on: 03/14/2021 08:01 pm »
I've used the rss api (which they use on the raw images site) to download images in an automated fashion using a small Python script. The api gives pretty detailed metadata about the images, including position information about the instrument that took the images. Aside from stuff that's obviously named, I haven't seen any official description of how to decipher that info, so unfortunately it's not very usable at the moment. They look like 3D vectors so maybe pitch, yaw and roll, but who knows.

Oh and if you're interested in processing raw images yourself, you can identify them from the name. If the third letter of the image name is "E" it's a raw image, although SHERLOC images (SI0 prefix) seem to be raw as well. It's also easy to recognize them visually since they have a visible Bayer pattern (kind of like a screen door) on them. The difficult part about them is that you'll have to "debayer" or demosaic the raw image to see it in color. I couldn't find any easy-to-use tool for demosaicing, so I wrote one myself that uses a simple demosaicing algorithm. It doesn't produce the best possible results (some color fringing around high contrast areas), but it's pretty usable nonetheless.

It would be very interesting to be able to filter mastcam images by azimuth and elevation, but I can't understand if it is possible.

I'm not sure if there are already some websites that allow you to do this, but the rss api does include mast azimuth and elevation for each image. So it's possible to whip up a program that filters by those values.

Offline spacexplorer

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Re: Perseverance/MARS2020 for developers
« Reply #8 on: 03/15/2021 07:05 am »

I'm not sure if there are already some websites that allow you to do this, but the rss api does include mast azimuth and elevation for each image. So it's possible to whip up a program that filters by those values.

Any specific example? I can only filter by camera:
https://api.nasa.gov/mars-photos/api/v1/rovers/perseverance/photos?sol=1&api_key=DEMO_KEY&camera=EDL_RUCAM

Offline lvm

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Re: Perseverance/MARS2020 for developers
« Reply #9 on: 03/15/2021 09:59 am »

I'm not sure if there are already some websites that allow you to do this, but the rss api does include mast azimuth and elevation for each image. So it's possible to whip up a program that filters by those values.

Any specific example? I can only filter by camera:
https://api.nasa.gov/mars-photos/api/v1/rovers/perseverance/photos?sol=1&api_key=DEMO_KEY&camera=EDL_RUCAM

Sorry, I should have stated that more clearly. I don't think the official APIs directly give you the ability to filter by azimuth and elevation with a single query. However, what you can do is download the metadata for images first, and then on your end do the filtering. Azimuth and elevation data is present in at least the RSS API responses. Not sure about the other APIs.

Unless NASA adds more filtering options to the APIs, you'll have to do any advanced filtering this way.

Here's an example response from the RSS API:

Quote
{"image":[{"extended":{"mastAz":"181.628","mastEl":"-32.2149","sclk":"668982844.091","scaleFactor":"1","xyz":"(31.8232,55.9169,-0.122529)","subframeRect":"(1,1,1648,1200)","dimension":"(1648,1200)"},"link_related_sol":"https://mars.nasa.gov/mars2020/multimedia/raw-images/?sol=23","sol":23,"attitude":"(0.43968,-0.00115686,0.0100415,0.898097)","json_link_related_sol":"https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&sol=23","image_files":{"medium":"https://mars.nasa.gov/mars2020-raw-images/pub/ods/surface/sol/00023/ids/fdr/browse/zcam/ZRF_0023_0668982842_596FDR_N0030770ZCAM03003_0630LMJ01_800.jpg","small":"https://mars.nasa.gov/mars2020-raw-images/pub/ods/surface/sol/00023/ids/fdr/browse/zcam/ZRF_0023_0668982842_596FDR_N0030770ZCAM03003_0630LMJ01_320.jpg","full_res":"https://mars.nasa.gov/mars2020-raw-images/pub/ods/surface/sol/00023/ids/fdr/browse/zcam/ZRF_0023_0668982842_596FDR_N0030770ZCAM03003_0630LMJ01.png","large":"https://mars.nasa.gov/mars2020-raw-images/pub/ods/surface/sol/00023/ids/fdr/browse/zcam/ZRF_0023_0668982842_596FDR_N0030770ZCAM03003_0630LMJ01_1200.jpg"},"imageid":"ZRF_0023_0668982842_596FDR_N0030770ZCAM03003_0630LMJ","camera":{"filter_name":"ZCAM_R0_RGB","camera_vector":"(-0.8455901810737076,-0.02402963157000776,0.5332914985993529)","camera_model_component_list":"(0.766708,0.437285,-1.9694);(-0.854432,-0.021398,0.519138);(-378.065,-8570.68,559.264);(4047.85,275.596,7555.65);(-0.852012,-0.0213123,0.523103);(3e-06,-0.318575,-0.270627)","camera_position":"(0.766708,0.437285,-1.9694)","instrument":"MCZ_RIGHT","camera_model_type":"CAHVOR"},"caption":"NASA's Mars Perseverance rover acquired this image using its Right Mastcam-Z camera. Mastcam-Z is a pair of cameras located high on the rover's mast.  \n\nThis image was acquired on Mar. 14, 2021 (Sol 23) at the local mean solar time of 12:40:11.","sample_type":"Full","date_taken_mars":"Sol-00023M12:40:11.660","credit":"NASA/JPL-Caltech/ASU","date_taken_utc":"2021-03-14T12:28:45.000","link":"https://mars.nasa.gov/mars2020/multimedia/raw-images/?id=ZRF_0023_0668982842_596FDR_N0030770ZCAM03003_0630LMJ","link_related_camera":"https://mars.nasa.gov/mars2020/multimedia/raw-images/?camera=MCZ_RIGHT&sol=23","drive":"770","title":"Mars Perseverance Sol 23: Right Mastcam-Z Camera","site":3,"date_received":"2021-03-14T21:39:54Z"}],"type":"mars2020-imagedetail-1.1","mission":"mars2020"}

As you can see the response data includes "mastAz" and "mastEl" fields which can be used for filtering.
« Last Edit: 03/15/2021 10:01 am by lvm »

Offline spacexplorer

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Re: Perseverance/MARS2020 for developers
« Reply #10 on: 03/15/2021 11:56 am »

Here's an example response from the RSS API:

Quote
{"image":[{"extended":{"mastAz":"181.628","mastEl":"-32.2149","sclk":"668982844.091","scaleFactor":"1","xyz":"(31.8232,55.9169,-0.122529)","subframeRect":"(1,1,1648,1200)","dimension":"

As you can see the response data includes "mastAz" and "mastEl" fields which can be used for filtering.
Yes, I've seen them,  but can't succeed with adding them to the url for server-side filtering, maybe it's not possible.

This code snippet performs local filtering on azimuth according to URL parameters; it would need the whole list of images as input, but I can get only one page at time (you must manually save API response to local file response.js to test the snippet):


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <body>
   <script src="response.js"></script>
   <script>

   // https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&page=20
   // >>> Manually save raw results into response.js

   imagesList = rawResponse.images;
   console.log("Total images count = ", imagesList.length);
   console.log(rawResponse);
   console.log(imagesList);

var url = new URL(window.location);
minAz =url.searchParams.get('minAz')
   if (minAz == null) minAz = 0;
maxAz =url.searchParams.get('maxAz')
   if (maxAz == null) maxAz = 360;
minEl =url.searchParams.get('minEl')
mexEl =url.searchParams.get('mexEl')


   results = imagesList.filter(
      function(item) {
         filtered  = ( (item.extended.mastAz >= minAz) && (item.extended.mastAz <= maxAz) );
          return filtered;
      }
   );

   console.log("Filtered: ", results.length);
   console.log(results);
   </script>
 
  </body>
</html>







Offline spacexplorer

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Re: Perseverance/MARS2020 for developers
« Reply #11 on: 03/15/2021 05:05 pm »
Found this page:

Perseverance Mars Rover Raw Image Playground

https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&page=0&num=50&order=sol+asc&search=|FRONT_HAZCAM_LEFT_A|FRONT_HAZCAM_LEFT_B|FRONT_HAZCAM_RIGHT_A| FRONT_HAZCAM_RIGHT_B|REAR_HAZCAM_LEFT|REAR_HAZCAM_RIGHT| NAVCAM_RIGHT|NAVCAM_LEFT&condition_2=0:sol:in&extended=sample_type::thumbnail,sample_type::full,product_type::raw

Split:

https://mars.nasa.gov/rss/api/?feed=raw_images&
category=mars2020&
feedtype=json&
page=0&
num=50&
order=sol+asc&
search=|FRONT_HAZCAM_LEFT_A|FRONT_HAZCAM_LEFT_B| FRONT_HAZCAM_RIGHT_A| FRONT_HAZCAM_RIGHT_B|REAR_HAZCAM_LEFT|REAR_HAZCAM_RIGHT|NAVCAM_RIGHT|NAVCAM_LEFT&
condition_2=0:sol:in&  // what is this?
extended=sample_type::thumbnail,sample_type::full,product_type::raw  // what is this?


Mastcam Z-left (MCZ_LEFT):
https://mars.nasa.gov/rss/api/?feed=raw_images&category=mars2020&feedtype=json&page=0&num=50&order=sol+asc&search=MCZ_LEFT&condition_2=0:sol:in&extended=sample_type::thumbnail,sample_type::full,product_type::raw
« Last Edit: 03/15/2021 05:10 pm by spacexplorer »

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Re: Perseverance/MARS2020 for developers
« Reply #14 on: 04/21/2021 12:00 pm »
I can't find in SPICE kernels nor Ingenuity, neither MHS (Mars Helicopter Scout) neither MHTD (Mars Helicopter Technology Demonstrator)  :-\

https://naif.jpl.nasa.gov/pub/naif/MARS2020/kernels/fk/m2020.tf

It simply does not exist:


The diagram below shows the M2020 frame hierarchy:


                                   "J2000"
                      +---------------------------------+
                      |               |<-pck            |<-pck
                      |               v                 v
                      |          "IAU_MARS"       "IAU_EARTH"
                      |          ----------       -----------
                      |               |<-fixed     
                      |               v             
                      |          "M2020_TOPO"      "M2020_SURFACE_FIXED"
                      |          ------------      ---------------------
                      |               |<-fixed          ^<-fixed
                      |               v                 |
                      |       "M2020_LOCAL_LEVEL"       |
                      |       --------------------------+
                      |               |                     
                      |               |                   "M2020_DLGA/DUHF"
                      |               |                   -----------------
                      |               |                       fixed-> ^
                      |               |                               |
                      |               |                               |
                      |               |  "M2020_PLGA/TLGA/PUHF/CMGA"  |
                      |               |  ---------------------------  |
                      |               |               fixed-> ^       |
                      |               |                       |       |
                      |               |  "M2020_SPACECRAFT"   |       |
                      |               |  ------------------   |       |
                      |               |     ^ <-fixed         |       |
                      |               |     |                 |       |
                      |               |     |   "M2020_CRUISE_STAGE"  |
                      |               |     |   --------------------  |
                      |               |     |     ^ <-fixed           |
                      |               |     |     |                   |
                      |               |     |     |   "M2020_DESCENT_STAGE"
                      |               |     |     |   --------------------
                 ck-> |               |     |     |     ^ <-fixed
                      |               |     |     |     |
                 "M2020_CACS"         |     |     |     |  "M2020_ROVER_MECH"
                 ------------         |     |     |     |  ------------------
                      ^               |     |     |     |     ^ <-fixed
                 ck-> |          ck-> |     |     |     |     |             
                      v               v                     
                                 "M2020_ROVER"
     +--------------------------------------------------------------+




Offline spacexplorer

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Re: Perseverance/MARS2020 for developers
« Reply #15 on: 04/22/2021 02:24 pm »
Write your own Ingenuity-based game with official NASA resources:
https://www.jpl.nasa.gov/edu/learn/project/code-a-mars-helicopter-video-game/

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Re: Perseverance/MARS2020 for developers
« Reply #16 on: 07/05/2021 07:48 am »
How to retrieve full data of Perseverance EDL using SPICE kernels.

SPICE kernels are a vey hard stuff to learn, but fortunately it is now available a web interface which makes think a little simpler. Just "a little", but sure better than playing with command line...

This is the page:
https://wgc.jpl.nasa.gov:8443/webgeocalc/#NewCalculation

A first semplification comes by selection of topic: do you want to retrive data of spacecraft trajectory? Select "State Vector" from the list:
https://wgc.jpl.nasa.gov:8443/webgeocalc/#StateVector

Are you interested on MARS2020/Perseverance? Select it from the drop down list "Kernel selection"; if it is not (yet) available, select  "manual" at bottom of list, and "choose kernels".

Click on "kernels", then "MARS2020", then "spk", so as to browse to \kernels\MARS2020\SPK folder of NAIF archive; click on the link to actually browse the folder in another window, because you need to know the date of each file, to figure out which one to select: indeed, there are several files with "EDL" in the name, but most of them are simulations and forecasts calculated months or years ago!

MARS2020 EDL landing occurred on 2021/02/18, so we need a file created after this date:

m2020_trajCEDLS-6DOF_ops_od069v1_AL4.bsp       2021-06-29 06:12  1.4M

Back to webgeocalc interface, select this file from the list: m2020_trajCEDLS-6DOF_ops_od069v1_AL4.bsp

SPICE/webgeocal needs also an additional reference kernel to calculate ephemeris for a spacecraft around Mars, which you must also select from the list:

MARS2020/kernels/spk/mar097s.bsp - ephemeris data of Mars

Now, in field "target name" you should select "MARS2020"; if you start typing "MARS2020" and the string is in the kernel, it will appear and you will be able to select it. Unfortunately, this works only if you selected a kernel from the ones available in the list... but you selected it manually! So this does not work: you need to know the "raw number" associated to MARS2020 mission.
Where to get this number?
From NASA Horizons site:
https://ssd.jpl.nasa.gov/horizons_batch.cgi

NASA Horizons usage is VERY complex, but for our task we only need spacecraft lists, whic you can get by specifying "*" as arguments of parameters COMMAND and CENTER:

https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27*%27&CENTER=%27*%27

Look for MARS2020 and you'll get:
-168  Mars2020 (spacecraft)                           Perserverance Ingenu

The negative number "-168" is what you are looking for. (Note: negative = spacecraft, positive = celestial body)

Now, put "-168" in "target name" field in webgeocalc interface.

For "Observer name" select "MARS".

For reference frame select "IAU_MARS"

In box "Input time" click on "Single interval".
Overall trajectory:
Start time: 2021-02-18 20:37
Stop time: 2021-02-19 20:46

Time step:
you can specify this in seconds, or you can specify the number of steps between start and stop time; for an overwiew of the overall trajectory, which lasts 5-6 minutes, you can use seconds, but if you want a very detailed chart of a short interval, you should use steps number.

For long time interval, specify step duration: input a number and select "seconds" or "minutes" from dropdown list
For short time interval, specify steps number:input a number and select "equal intervals" from list.


Note: WebGeocalc can only calculate 50'000 data points in a single calculation

Atmosphere entry:
Start time: 2021-02-18 20:37:00
Stop time: 2021-02-19 20:39:00
Time step: 100 intervals

Parachute:
Start time: 2021-02-18 20:40:30
Stop time: 2021-02-18 20:41:15
Time step: 100 intervals

From powered descent to landing:
Start time: 2021-02-18 20:42:30
Stop time: 2021-02-18 20:45:00
Time step: 300 intervals

Skycrane phase:
Start time: 2021-02-18 20:43:10
Stop time: 2021-02-18 20:44:00
Time step: 300 intervals

You can also manually zoom in the charts by clicking and dragging horizontally and vertically the mouse.

State representation: select Planetographic or Planetodetic to get data as altitude w.r.t. surface, together with latitude and longitude.

Coordinate systems is a very complex topic, see official documentation for details.
In a nutshell:
Planetocentric: Longitude: -180/+180, Latitude: -90/+90, Radius
Planetodetic: Longitude: -180/+180, Latitude: -90/+90, Altitude - Takes into account real body shape (ellipsoid)
Planetographic: Longitude: 0/360, Latitude, Altitude  - Takes into account real body shape (ellipsoid)

Time series plots: select Altitude, Speed and whatelse you need to be plotted.


Offline spacexplorer

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