Kilometers on the ground Options

[Glevesque]

Hello everyone !

I would like to know more about the mileage grid on the ground. I have difficulty finding precise data from various unofficial sources.

Here is my list:

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Bonjour a tous !

J'aimerais avoir des précisions sur la grille de kilométrage parcourus au sol. J'ai des difficulter a trouver des données bien précises à différentes sources non officiel.

Voici ma liste :
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1 km Sol 335, 17 juillet
2 km Sol 363, 14 août
3 km Sol 403, 24 sept
4 km Sol 431, 22 oct
5 km Sol 521, 23 janv
6 km Sol 568, 12 mars
7 km Sol 641, 26 mai
8 km Sol 668, 23 juin
9 km Sol 709, 4 août
10 km Sol 957, 16 avril
11 km Sol 1296
12 km Sol 1439
13 km
14 km Sol 1448
15 km
16 km Sol 1669

[tanjent]

Even if the slippage could be precisely accounted for, how could we settle on a definition of "distance traveled"?
It's like trying to compute the exact length of the coastline of France.
Any path with self-similar irregularities down to an infinitely small scale is not going to have a unique length unless you first specify the radius of measurement.

Ok, maybe a wheeled vehicle has a minimum turning radius, but in three dimensions the terrain will still cause infinitely small bumps that need to be factored in if you want the "exact" distance, and many of these will have occurred in between measurements. It will always be necessary to simplify the true path to a series of segments, and the distance between stopping points seems like the most expedient segment to use for most purposes.

[RoverDriver]

.... and the distance between stopping points seems like the most expedient segment to use for most purposes.

I was not trying to be pedantic but really it all depends what you are trying to measure. For me it is mostly to measure the wear and tear on the vehicle, so to me discarding all twists and turns is definitely not the way to go. Only rarely we drive in a single straight line, most of the time we have two, three, even five segments with large turn in place (every 90 deg turn in place corresponds to about 5m of wheel motion!). Since we have been trying to reduce wear and tear on the wheels drive paths have been quite tortuous and I would not be surprised to find out that just connecting the end of drive coordinates would underestimate by more than 30%.

Paolo

PS: I finally ran some numbers. Missionwide, the difference between reported odometry (*) and straight line distance between start and end of drive on average is 35.5%.
(*) reported odometer: odometer as reported by the vehicle.

[Glevesque]

I was not trying to be pedantic but really it all depends what you are trying to measure. For me it is mostly to measure the wear and tear on the vehicle, so to me discarding all twists and turns is definitely not the way to go. Only rarely we drive in a single straight line, most of the time we have two, three, even five segments with large turn in place (every 90 deg turn in place corresponds to about 5m of wheel motion!). Since we have been trying to reduce wear and tear on the wheels drive paths have been quite tortuous and I would not be surprised to find out that just connecting the end of drive coordinates would underestimate by more than 30%.

Paolo

I apologize in advance for having very poorly expressed myself in my previous positions, and I greatly thank all those who participated in this discussion, as well as providing valuable assistance that gave a better understanding of the challenges of Driving the rover on Mars. Indeed, I understand the dilemma of driving the rover facing the premature wear of its wheels. And this is of utmost importance to potentiate a longer mission of Curiosity on Mars. In fact, my question was just to know where I could find reliable data to reproduce on a mileage map traveled according to the trajectory, the answer that my nogal given is greatly satisfactory on this. If I asked this question, it is because the three sources that serve as my reference have different data on daily distances traveled, and I wanted to understand where this difference comes from.

I thank you all.
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Je m'excuse d'avance de m'avoir très mal exprimé dans mes postes précédant, et je remercie grandement tout ceux qui ont participé à cette discussion, tout en y apportant une aide précieuse qui a donnée une meilleurs compréhension sur les défis de la conduite du rover sur Mars. Effectivement, je comprend bien le dilemme sur la conduite du rover faisant face à l’usure prématurée de ses roues. Et cela est d'une très grande importance pour potentialiser une plus longue mission de Curiosity sur Mars. En fait, ma question était juste de savoir ou je pouvais trouver des données fiables pour reproduire sur une carte de kilométrage parcourus en fonction de la trajectoire, la réponse que ma donné nogal est grandement satisfaisante à ce propos. Si j'ai posé cette question, c'est que les trois sources qui me sert de référence ont des données différentes sur les distances journalière parcourus, et je voulais comprendre d’où viens cette différence.

Je vous remercie tous.
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Exemple with Sol 967 :

1- Midnight Planets : http://www.midnightplanets.com/web/MSL/sol/00967.html
2- Curiosity Drive Log : http://www.curiositymsl.com/tracking/drivelog.html
3- Curiosity Rover's Location/JPL-Nasa : https://mars.jpl.nasa.gov/multimedia/images/?ImageID=7148

[Glevesque]

I would also like your help to trace the daily cumulative distances (per Sol) that were greater than one hundred meters. Here is the list that I was able to come out on this subject:

PS: I did not find the distance record assuming the Sol 976 of 262.41 meters (May 2015)
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J'aimerais également votre aide pour retracer les distances cumulatifs journalière (par Sol) qui ont été supérieurs au cent mètres. Voici la liste que j'ai pu resortir a ce sujet :

PS : Je n'ai pas retrouver le supposer record de distance au Sol 976 de 262.41 meters (mai 2015)
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Curiosity Rover's Location (Nasa/JPL)
Analyst's Notebook entry for Sols
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Sol - Dist(m) - Earth Date - Information sources
385 - 128.81 - 06/11/2013 - https://mars.nasa.gov/multimedia/images/?ImageID=5549
419 - 117.84 - 11/10/2013 - https://mars.jpl.nasa.gov/multimedia/images/?ImageID=5649
657 - 112.63 - 12/06/2014 - https://mars.jpl.nasa.gov/multimedia/images/?ImageID=6319
661 - 109.35 - 16/06/2014 - https://mars.jpl.nasa.gov/multimedia/images/?ImageID=6342
662 - 123.88 - 17/06/2014 - https://mars.jpl.nasa.gov/multimedia/images/?ImageID=6344
665 - 121.60 - 20/06/2014 - https://mars.nasa.gov/multimedia/images/?ImageID=6350
668 - 104,85 - 23/06/2014 - https://mars.jpl.nasa.gov/multimedia/images/?ImageID=6366
671 - 113.58 - 26/06/2014 - https://mars.jpl.nasa.gov/multimedia/images/?ImageID=6372

Source : https://an.rsl.wustl.edu/msl/mslbrowser/tab.aspx?t=MP