Mars Curiosity Rover Project

Over the Fall 2016 and Spring 2017 semester, WCC student Tianna Barber, under the mentorship of Dr. Joseph Ciotti and Dr. Peter Mouginis-Mark analyzed images from the Mars Curiosity Rover, which is a Mars Science Laboratory that landed inside Gale Crater on August of 2012. The rover has outlived its life expectancy by over two years (currently on Sol 1512) and is still going strong towards its destination—the base of Mt. Sharp. The whole purpose of Curiosity’s mission is to investigate Martian climate and geology as well as analyze the soil for evidence of pre-existing life; seeing if Mars was once habitable.

Project Objectives:
The objective of this project was to compare panoramic and orbital images of the NW rim of Gale Crater and identify similarities in geographic features, as well as map out the features location, elevation, and distance from where the rover was when the panorama was taken. Then verify we correctly identified corresponding features in both views. The Curiosity panoramic pgotos were compasred with the Mars Orbiter Laser Altimeter Digital Elevation Model. In the follow-up dstudey in Spring 2017, various mathematical corrections were used to adjust the elevation calculation.

Project Results:
     • The results of the Fall 2016 are summarized in the Mars Curiosity Poster 2016.

During Spring 2017, more refined mathematical analysis was conducted which adjusted elevations based on the curvatire of Mars and perspective error. By incorporating this mathematical procedure, the average percent error between DEM (Digital Elevation Model) and panoramic calculations was approximately 1.4% as opposed to 8% when these corrections were not taken into account.

     • The results of Spring 2017 are summarized in the Mars Curiosity Poster 2017.

Methodology
We used a few different methods to reach this objective. The first being able to locate Curiosity’s exact location when it captured this panoramic photograph back in March on Sol 1284 as viewed from Naukluft Plateau. We were able to locate its location based off of high resolution MRO photographs as well as Curiosity traverse maps release by NASA and MSL. Once located, we used information released by NASA about the panoramic image, which told us the azimuth and distance of peaks A, B, and C, allowing us to find North on the photograph. From there, we were able to find the azimuth and distance of each feature from an orbital image, then compare with horizontal (azimuth) spacing on the panorama.

Next we wanted to find the elevation of the features. As there is no sea level on Mars and the elevations are based off the planet's global datum, it was a bit tricker than finding the azimuth. Using MOLA DEM (Mars Orbiter Laser Altimeter Digital Elevation Model) data, we found the lowest point in Gale Crater to be -4545 meters. Using orbital topographic maps and DEM data, we were able to find elevations of nearly all identified features. Using vertical spacing on the panorama with the baseline of feature H, and the lowest point in Gale crater, we found their actual elevation in meters.

This project resulted in identification of 54 features. These tables show the calculations for all the azimuths as well as elevations. Overall, there was hardly a margin of error when it comes to the azimuths, but there was with the elevations. We believe there are a few reasons for this error. First, the DEM data has a spatial resolution of approximately 24x24 meters per pixel, leaving room for quite a bit of variation in elevation, especially in mountain peaks. The vertical height accuracy is expected to be between 3-5 meters, with the elevations we used to be generally good for 10-12 meters, but it’s still hard to be certain with no ground truth. A second reason for this margin of error could possibly be due to the curvature of the planet because the identified features furthest away, have the largest error. This error was addressed in the Spring 2017 follow-up project.

But overall we believe the results of this initial project were successful, and that these methods could be used to help with future mission planning and operations.

                            Tianna Barber                       Tianna Barber and mentor Dr. Joseph Ciotti