For the second summer, Lawrence Livermore National Laboratory's (LLNL) Space Science Institute (SSI) welcomed undergraduate and graduate students to a 10-week internship exploring astronomy, cosmochemistry and astrophysics. Throughout the summer, the 2026 student cohort worked alongside their LLNL mentors on projects reflecting the variety of capabilities available onsite at the Laboratory.
"Here at the Lab, there is a huge breadth of research that lives under space science - from performing astrophysical data analysis with LLNL's high-performance computers to characterizing an instrument in the laboratory to doing chemistry with meteorites," said Peter McGill, SSI student research and engagement coordinator.
"Of course, the students have their own particular discipline or interest, but when they come onsite here, they are also exposed to an array of other research fields through the SSI seminar series that we have," added Thomas Kruijer, SSI student research and engagement coordinator.
For many students, their summer projects and onsite experiences help guide them in the next steps of their academic journey and professional development.
Detector calibration
For recent University of California (UC), Berkeley graduate Kai Marshall, the SSI internship offered him a chance to dive into X-ray astronomy, a research area that is not widely taught in school.
Over the summer, Marshall worked to calibrate the energy measurements of the Resolve detector - the core instrument on the X-ray Imaging and Spectroscopy Mission (XRISM). XRISM is an international space mission supported by the Japan Aerospace Exploration Agency (JAXA), National Aeronautics and Space Administration (NASA) and European Space Agency (ESA).
Resolve is made up of a 6-by-6 array of tiny detector pixels. When an X-ray photon from an object in space strikes ones of the pixels, it produces a tiny temperature increase. Because the size of that increase corresponds to the photon's energy, scientists can determine the energy of each incoming X-ray.
Due to the detector's sensitivity, even a small temperature change in one of its pixels can affect how it interprets an incoming X-ray. While most pixels collect calibration data periodically, one dedicated pixel continuously records a known-energy calibration signal, allowing researchers to track temperature changes over time.
With these measurements, Marshall helped refine estimates of each pixel's temperature over time, improving the calibration relationship that converts raw detector signals into an estimate of an X-ray photon's energy. While investigating why some of the data fits used in the calibration process were unsuccessful, he learned how to diagnose problems in complex scientific software and data.
This work has given Marshall a look at the full data pipeline - the series of steps that transforms raw measurements from a spacecraft into scientific results. His internship has also provided him with the opportunity to both contribute to an international space mission and explore his own future in observation and instrumentation. "I wanted to work on something that was more tangible," Kai said. "This feels like I am having an impact."
By improving the accuracy of Resolve's measurements, he is helping ensure that the instrument can fulfill its promise: providing researchers with an unusually detailed view of the hottest, most energetic and most dynamic objects in the universe.
Instrumentation modernization
While Marshall worked to ensure that the X-ray energies recorded in space are measured accurately, Luis Garcia, an SSI intern sponsored by the Livermore Lab Foundation (LLF), worked to modernize the Electron Beam Ion Trap (EBIT) - a laboratory instrument that helps scientists interpret X-rays from extreme objects in space.
When an observatory, like XRISM, detects X-rays from a supernova remnant, a black hole or another extreme object, scientists can compare the observed spectral lines (specific energies or wavelengths of light) with measurements made at EBIT. This can reveal not only which elements and ions are present but also information about an object's temperature, density and motion.
While the EBIT facility has been continually upgraded to meet evolving scientific needs since it was first invented in the late 1980s, it still relies on legacy hardware and software. This means many of its older electronic modules are no longer manufactured, and the existing software depends on aging computers that have become increasingly difficult to replace.
To help modernize one of these legacy systems, Garcia, an undergraduate student at UC San Diego, upgraded one of the data-acquisition systems that collects and process signals from EBIT's spectrometers - instruments that measure and analyze the light emitted by ions.
First, he had to test how the new hardware and software would interact with each other. To do this, he used a waveform generator to create simulated signals with specified strengths, durations and shapes. Those signals were then sent through nuclear instrumentation modules, which are used to process the signals, and then into the new hardware and software.
Next, Garcia verified that the system accurately recorded the generated signals. If he fed it a signal with a known strength, for example, the software should report the same value. After validating the hardware and software, he then moved onto using real signals from EBIT and comparing them to the old system.
Garcia noted that much of this work involved studying old manuals and technical data sheets to understand how the new components interact. "Not a lot of people use these systems [because of how unique they are], so I am failing my way through it and learning as I go," he said.
The modernization is not only expected to make the system more robust and capable of handling higher count rates, but its newer computers will also have improved memory capabilities to support more real-time data analysis during measurements.
By replacing these outdated systems now, while the old system is still operational, the SSI team is reducing the risk that a single component could interrupt the facility's work in the future.
Searching for stardust
In a completely different realm of space science, Caitlin Gallagher, an international student from the United Kingdom, spent the summer preparing and analyzing meteorites in search of presolar grains - tiny particles of stardust.
Found in meteorites, presolar grains were formed inside stars before our solar system existed. Their chemical and isotopic compositions preserve clues about those stars and the environments in which they formed. To locate the grains, Gallagher and her mentor first assembled a gold mount, on which meteorite particles were distributed. Then, using scanning electron microscopy (SEM), they examined the particles to identify candidate grains.
Once a grain is found with SEM, researchers need additional confirmation that it is, in fact, a presolar grain. To confirm the grain's origin, they need to analyze its isotopes using mass spectrometry techniques. For presolar grains, researchers use nanoscale secondary ion mass spectrometry, or NanoSIMS, to measure lighter elements such as carbon, nitrogen, oxygen and silicon. If it is a presolar grain, NanoSIMS will reveal that its isotopic ratios are extremely different from that of typical solar-system material.
After NanoSIMS, researchers use resonant ionization mass spectrometry to measure heavier elements - including zirconium, titanium and molybdenum - revealing clues about the type of star that produced the grain. Finally, there is noble gas mass spectrometry, which measures elements such as helium and neon to obtain the age of the grain.
Prior to coming to LLNL, Gallagher, who recently graduated with a bachelor's in physics with medical physics at University College London, had only learned about the theories behind SEM and mass spectrometry. "It's so different actually using a machine in practice compared to just learning the equations behind it," she said.
Having access to even one of the mass spectrometers used in this research, much less three in a single building, is quite rare and underscores the uniqueness of the SSI internship. "With access to all of these different machines, LLNL feels like a science theme park," said Gallagher.
-Shelby Conn
