2024-01-15

3-D Print Your Own Mastcam-Z Cal Targets!

by guest blogger Sarah Al-Ahmed from The Planetary Society

The touchdown of NASA’s Perseverance rover on Mars in 2021 holds a personal significance for me that goes beyond pure scientific achievement. I had the rare privilege of witnessing the rover at JPL before its voyage to the launchpad. That viewing was among my final pre-pandemic outings with friends before the world entered a COVID-19-induced stasis, and it meant the world to me.

In the whirlwind year that followed, our planet and my life underwent transformative changes. I began an exciting new job at The Planetary Society and (virtually) met many amazing people who worked on space missions. Among them was my coworker, Mark Hilverda, who played a part in designing the Perseverance rover’s primary Mastcam-Z calibration target in collaboration with the Mastcam-Z team. The calibration targets on Perseverance are crucial components intended to help calibrate the rover’s cameras for accurate color rendering on the Martian surface. My coworkers were so proud of the role we played in the design, and their enthusiasm was infectious.

Despite the distance imposed by the pandemic, our organization knew that we had to honor Perseverance’s touchdown on Mars. With simultaneous missions from the USA, UAE, and China arriving at Mars within days of each other, it was the celebratory moment we all needed. The Planetary Society hosted Planetfest ’21, a virtual celebration, and extended the invitation to our global membership, ensuring that, even in isolation, no one had to celebrate the historic moment alone.

In the days after Perseverance descended from its sky crane down to the Martian surface, I sought an art project to commemorate the achievement and the new phase of my career. Of course, I found my inspiration when the first picture of the Mastcam-Z primary image calibration target popped into our work chat with a shower of congratulatory emojis.

The Creation Process:

Digitizing a complex design into a 3D model can be complicated, but I was able to gain access to the original 3D models that Mastcam-Z team members Kjartan Kinch and Morten Bo Madsen and colleagues in Denmark used to fabricate the flight targets. I got the files from Jim Bell, the past president of The Planetary Society’s Board of Directors, a professor at Arizona State University, and the Principal Investigator for Perseverance’s Mastcam-Z instruments. I used these 3D models as the starting point for this project.

The Mastcam-Z primary calibration target contains a motto, graphics, and a sundial in its design, which I wanted to incorporate into the 3D rendering. Using images of the calibration target’s design, I transformed these details into PNGs, which I converted into 3D models and added to the original files. The result is a richly detailed 3D representation of the Mastcam-Z primary calibration target that anyone with a 3D printer can make and keep for their space collection.

What’s in this file bundle?

To make sure users have a comprehensive toolkit for their 3D modeling journey with the Perseverance Mastcam-Z calibration targets, this bundle of images, 3D models, and Blender files has been thoughtfully crafted. Here’s what’s inside:

Original Files:

The original 3D models of the calibration targets do not come with any symbols or additional details. By clicking on these links you’ll find these STL-format (“stereolithography”) files that should work with typical 3-D printers:

● primary_caltarget_base: The foundational base of the Mastcam-Z primary calibration target.
● ShadowPost: Otherwise known as the gnomon, this is the shadow post component for the primary calibration target.
● secondary: The Mastcam-Z secondary calibration target, an auxiliary model.

New Files:

Dive into the added details of the primary calibration target with these enhanced files:

● Calibration-Target-Details: Just the intricate details, detached from the primary target. This file is for those looking to rescale or tweak specific details.
● Calibration-Target-Details-Extrusion: On this model, the details pop out or “extrude” from the calibration target’s surface.
● Calibration-Target-Details-Intrusion: Here, the details are carved or “intruded” into the surface, offering a recessed look.
● Calibration-Target-with-Details (this is a “Blender” file): For those working with Blender (a free 3D modeling software) at home, the original primary image calibration target and the Calibration-Target-Details are overlayed as two separate objects, granting you the flexibility to resize and modify as you please.

PNGs:

For those who want a more graphic approach, a dedicated set of PNG files awaits. These offer various versions of the calibration target details:

● 3D-Prints-3.png

● Calibration-Target-Center.png

● Calibration-Target-Symbols-and-Colors.png

● Calibration-Target-w-Spaces-no-center.png

● Calibration-Target-w-Spaces.png

Feel free to change these details by tweaking the PNGs. Once satisfied, convert your masterpiece into an SVG (like the example you can download here: Calibration-Target.svg.svg). You can extrude these designs with tools like Blender, marrying them seamlessly with the original calibration target model.

Dive Deeper

For more information on Perseverance’s calibration targets, you can read our article Calibrating Mars, which was published in the December Solstice 2020 edition of The Planetary Society’s quarterly magazine, The Planetary Report, and check out the “Mars in Full Color” blog about the Mastcam-Z cal targets here on this site as well.

Happy modeling, everyone!