In October 2019, we announced that First Mode and Western Washington University were awarded a NASA contract to develop technology for geological research. The tool being developed, which is called a goniometer, will be used in a lab on Earth to help us better understand what orbiters and rovers measure on other planetary surfaces.
With Perseverance landing shortly on Mars, we thought this would be a good opportunity to catch up with the goniometer’s lead engineer, Kathleen Hoza, on progress to date. Kathleen helped lay the groundwork for the project by creating a prototype goniometer while pursuing her M.S. degree in geology at Western Washington University under the tutelage of Prof. Melissa Rice. Now, Kathleen and Prof. Rice are working together to get the new and improved goniometer across the finish line and ready to start analyzing rocks!
What kind of research will the goniometer help with?
Spacecraft on other planets use a combination of techniques to tease out information about the composition and structure of rocks. Once we know that information, we can make inferences about the environment and timing of those rocks’ formation, and that can help answer big-picture science questions. For example, we’ve used a technique called reflectance spectroscopy to determine that Mars rocks contain minerals that could only have formed in a long-lasting water-rich environment – exactly the kind that could have supported life. Geological research on other planets can also help us to understand the basic prss that form and alter planets, including our own Earth.
How does the goniometer relate to the Perseverance rover?

One of the major techniques for studying rocks on other planets is reflectance spectroscopy, which involves measuring energy at specific wavelengths of light that are emitted by the Sun, bounce off rocks, and then enter a detector on the spacecraft. Different rocks absorb and reflect different wavelengths of light, and we can tell them apart based on their specific spectroscopic signatures.
But, in order to understand what we are seeing when a rover takes a measurement on Mars, we have to know what we’re looking for. This means going out into the field on Earth, collecting rocks we think might be similar to Mars (or Moon, or Venus…) rocks, and then taking measurements in a lab on Earth in a way that is very similar to a spacecraft taking a measurement on a different planetary surface. This is called an analog study, and analog studies anchor our understanding of geological measurements taken in space.

In order for these analog studies to be useful, we have to make sure that we are accurately replicating the conditions the spacecraft will experience. This is where the goniometer comes in. In space, the angular position of the Sun in the sky and the angular position of the detector on the spacecraft relative to the target rock surface can influence the measurement. In the lab, a goniometer lets us carefully position a light source so as to simulate all different times of day, and also to position a detector to simulate all different positions of the spacecraft relative to the surface.

By taking measurements in many different angular positions, we can build up a spectral library that we can use to cross-check against spacecraft measurements. Ultimately, this leads to a better understanding of surface geology, which in turn contributes to the search for past life and the quest to better understand how planets (including Earth) form and evolve.
The team working on the goniometer has been collaborating closely with the Perseverance science team (including Prof. Rice, who will be helping to guide rover operations when it lands), and the goniometer has been designed with Perseverance’s instruments, environment, and science goals in mind.
What is a milestone you’re preparing for in the coming weeks? What’s the significance of achieving this milestone?
We are getting ready to start system-level testing on the goniometer. If these tests go well, it will mean we’re ready to start taking measurements of rocks and answering science questions!
What are some of the first rocks the goniometer will characterize?
Once the goniometer arrives at WWU, some of the first rocks it will study will come from something called the Mastcam-Z geoboard. This set of rocks was used to help calibrate an instrument on board Perseverance, and measuring these exact same rocks on the goniometer will help us to be certain our measurements are relevant to Perseverance’s measurements on Mars.
What is the most exciting thing for you about your work on the goniometer?
To me, the most exciting part of the goniometer project is how it has brought together incredible people from across different disciplines and situations. The team that’s worked on the goniometer includes scientists, engineers, interns, and students, and every person I’ve had the opportunity to work with has brought something different and valuable to the table. In general, I believe the more we can get people stepping outside their own immediate circles and talking to bright people working in different areas, the more problems we can solve and the better we will do.
Now that Perseverance is in space and landing soon, do you have any additional thoughts about the opportunities for geological exploration on Mars?
When Perseverance lands, it will be in a site called Jezero Crater, which is an ancient lakebed on Mars. This site was selected for all kinds of excellent reasons, including high potential for preserving signs of past life that we might be able to detect either using Perseverance’s instruments or by caching and collecting samples for return to labs on Earth.
However, the part I’m most excited about will (hopefully) come a few years down the road in Perseverance’s extended mission to a place called NE Syrtis. In NE Syrtis, the ancient “basement” of Mars is exposed, and we will have the opportunity to directly study primary crust, the very first rocks that formed from Mars’ primordial magma ocean. Studying NE Syrtis could lead to entirely new insights into what young planets look like and how they change.
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