The Role of LIBS in ChemCam and SuperCam: An Interview with Kelsey Williams, Part III

For our National Space Day content series, we are spotlighting the latest research in the field of space exploration, featuring experts in this field who are using spectroscopy to advance space exploration. In this extended Q&A interview, we sit down with Kelsey Williams, a postdoctoral researcher at Los Alamos National Laboratory (LANL), who is working on planetary instrumentation using spectroscopic techniques such as laser-induced breakdown spectroscopy (LIBS) and laser ablation molecular isotopic spectrometry (LAMIS) (1–3).

Kelsey Williams is a postdoctoral researcher at Los Alamos National Laboratory (LANL). Photo Credit: © Kelsey Williams.

In Part II of our conversation with Williams, she talks about the potential of mass spectrometry (MS) in space exploration applications. In Part III, Williams goes into detail about ChemCam and SuperCam and how LIBS is used in both these instruments.

Could you discuss a specific example of a spectroscopic instrument or technique developed at LANL that has been or is currently being used in space exploration? What were the key scientific objectives of that instrument?

ChemCam and SuperCam are two instrument suites that were developed here at Los Alamos. ChemCam is a LIBS instrument that also has a context imager or camera. So, the instrument has both the LIBS laser detector and all the optics for that, but it also has a camera so you can look at the spot that was targeted, and it can do this out to seven meters, which is an incredible standoff distance. These are located on the top of the rover.

A group of scientists will pick out the target, ablate it, observed the plasma, and determine the elemental composition of the sample. SuperCam is similar in that it is a LIBS instrument, and it does have an imager. The imager on the SuperCam instrument is colored, whereas on ChemCam, it is not a colored imager. SuperCam also has a Raman instrument on it, and it is also capable of luminescence and infrared (IR) experiments. It also has a microphone, so some scientists are performing acoustic experiments as well.

ChemCam has been on Mars over 10 years and SuperCam has been on Mars for just over 4 years, and both are still collecting data and providing us with new information. Almost daily, you can look in the news and see all the information that we're gathering from Perseverance and Curiosity. The purpose of these instruments is to understand the elemental composition of the Martian crust. On the SuperCam instrument, you also get mineralogical information, and it can also look for a kind of biosignature as well, because you get more molecular information with Raman and infrared techniques.

What are some of the unique challenges and considerations when designing spectroscopic instruments for deployment in the harsh environments of space, such as extreme temperatures, radiation, and vacuum? How does LANL address these challenges in its instrument development?

One of the big things is making sure that the casing of the instrument is something that can't be damaged by radiation. So, there is a lot of care taken into consideration for the materials that the instruments are made up.

We have amazing engineers here at LANL that know all of that. I'm on the side of determining how to make the instrument. What information do we need to get and what are the requirements that we need to get useful information? We take it to our engineers, and they provide the best material that will work in this kind of environment.

In addition to that, all the stages that are involved in getting the instrument to a planetary body are also evaluated. They're called shock and vibration tables. So, a design of an instrument will be placed onto one of these shock and vibration tables, and it's meant to simulate what the instrument will go through when it is launched into space and lands on another planet. The table will give the instrument a large impulse and various levels of vibration and see how robust the instrument is in enduring that kind of event. Additionally, we have a thermal vacuum chamber. It's a large chamber that can come down to a vacuum, and it is capable of a thermal cycle. It'll cycle it through some sort of temperature pattern that it would be expected to encounter when it is on either a planetary body or when it's just in space, to see how those components withstand those kinds of conditions. Without an atmosphere, temperature changes are intense in space, so you have to make sure that you know anything that is expanding or contracting doesn't actually cause your optics to shift, or that even in the contracted or expanded state, the optics are still capable of working. Like I mentioned, we have an incredible team of engineers that can do these kinds of tests for us.

Something else we need to consider is what’s called the SWaP. It's the size, weight, and power consumption of the instrument. So, for instance, ChemCam and SuperCam are part of what's called a flagship mission. The rover itself is kind of a machine that's driving through Mars, but scientific teams compete to get a spot on the rover and to get their instrument on that rover. Therefore, you must be considerate of the amount of space that your instrument will take up. You don't want to be taking something huge and heavy to other spaces. It's just going to take up too much energy. And we must consider what the power consumption is, because if you have something that's consuming a ton of power, it's just not efficient when you're trying to get as much information as possible. So those are some of the things that we need to consider when making these types of instrumentation.

References

1. Wetzel, W. The Impact of LIBS on Space Exploration: Mars. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/the-impact-of-libs-on-space-exploration-mars (accessed 2025-04-23).
2. McMillan, N. Laser-Induced Breakdown Spectroscopy (LIBS). Carleton.edu. Available at: https://serc.carleton.edu/msu_nanotech/methods/libs.html (accessed 2025-04-23).
3. Wetzel, W. Celebrate National Space Day with Spectroscopy. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/celebrate-national-space-day-with-spectroscopy (accessed 2025-04-23).