Inside UC San Diego’s Out-of-This-World Impact

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UC San Diego’s reach doesn’t stop at Earth’s atmosphere. 

Our astronauts have walked in space, our scientists have tested medicines in orbit and our astrophysicists have uncovered new planets and helped explain some of the universe’s biggest mysteries. These discoveries, powered largely by federal investment in science, make America stronger at home while pushing the limits of human exploration.

In honor of World Space Week, an international celebration of science and technology coordinated by the United Nations, we’re highlighting a few of UC San Diego’s cross-disciplinary contributions to space science.

Did you know: 

1. UC San Diego has produced four NASA astronauts — all women.

When it comes to spaceflight, Tritons have played a role in some unforgettable firsts. Kate Rubins ’99 made history in 2016 as the first person to sequence DNA in space, proving that genetic science can be done in microgravity. Just a few years later, Jessica Meir, PhD ’09 stepped outside the International Space Station to join NASA’s first all-woman spacewalk in 2019, a milestone that resonated around the world. In 2021, Megan McArthur, PhD ’02 became the first woman to pilot the SpaceX Crew Dragon on a mission to the International Space Station. And most recently, Deniz Burnham ’07 completed two years of training to earn her astronaut wings as part of NASA’s 23rd class, preparing her for future missions to the moon, the space station or even Mars.

2. UC San Diego scientists were key players in NASA’s landmark Twin Study of astronaut health.

It was one of those rare science stories everyone seemed to be talking about: Astronaut Scott Kelly spent nearly a year on the space station while his identical twin brother, Mark, stayed on Earth. Researchers at UC San Diego School of Medicine helped lead the effort to analyze the brothers down to the molecular level, comparing changes in their genes, immune systems, vision, cognition and more. The results offered an unprecedented look at how the human body adapts — and sometimes struggles — during long-duration spaceflight, knowledge that is reshaping how NASA plans for the next era of exploration.

3. Space travel speeds up stem cell aging — and our scientists saw it in action.

Building on the findings of NASA’s Twin Study, researchers at UC San Diego’s Sanford Stem Cell Institute — a global hub for stem cell science and innovation in space — recently sent blood-forming stem cells to the space station to see how they changed in microgravity. The study found that in just weeks, the cells showed signs of aging much more quickly than on Earth, but some damage reversed once they returned home — hinting that aging cells might be restored with the right interventions. Such evidence gives scientists new clues about how spaceflight affects astronauts’ health and how studying the body in orbit can teach us more about aging on Earth.

4. Our astrophysicists helped uncover a multi-planet system beyond our solar system.

The discovery of the first known star system with seven Earth-size planets in 2017 offered a glimpse into just how many worlds might exist beyond our own — and even raised questions about whether some of them could support life. UC San Diego astrophysicists helped characterize the TRAPPIST-1 star at the center of that system, measuring its temperature, gravity, elemental makeup and magnetic activity to determine its potential habitability. Their work added crucial context to one of the most remarkable planetary discoveries in recent years.

5. An AI tool from UC San Diego could help protect astronauts’ eyesight in space.

Vision loss is one of the biggest health risks astronauts face, and not something you want to discover once you’re already in orbit. This year, researchers from the Shiley Eye Institute and Viterbi Family Department of Ophthalmology teamed up with the School of Computing, Information and Data Science  and harnessed the power of the Expanse system at the San Diego Supercomputer Center to train an artificial intelligence tool that can flag these risks ahead of time. By analyzing detailed eye scans, the system can predict who is most vulnerable, and could give NASA a chance to protect vision before crews ever leave the ground. 

6. From Apollo to Artemis, UC San Diego scientists are following the water — on the moon and on Mars

Finding water is essential for sustaining life beyond Earth and planning long-term missions.  When Apollo 11 astronauts returned with lunar samples in 1969, Nobel laureate Harold Urey and chemistry professor James Arnold at UC San Diego were among the first to study them. Urey also was among the first to suggest that water could exist in the moon’s permanently shadowed polar craters. Building on that legacy in a study released earlier this year, atmospheric chemist Mark Thiemens and his team analyzed lunar data and discovered that most lunar water likely came from the moon itself or comet impacts — not from solar winds, as once believed. The findings shed light on the moon’s history and could help guide NASA’s Artemis program as it prepares for long-term missions.

At Scripps Institution of Oceanography, geophysicist Vashan Wright analyzed data from NASA’s InSight lander, co-authoring a 2024 study that found that liquid water may be stored deep beneath the surface of Mars. Together, these studies point to where future explorers might one day find the most vital resource in space.

7. UC San Diego was the first to test cancer drugs in space aboard a private astronaut mission.

As part of Axiom Mission 2, scientists from the Sanford Stem Cell Institute launched tumor models into orbit to study how cancer cells respond to treatment in microgravity. Space accelerates the way some cells change and become resistant to therapy — a process that can take much longer to track on Earth. By testing cancer drugs in this unique environment, researchers hope to uncover new approaches that could improve treatments for patients both in space and on the ground.

8. Our astrophysicists are helping explain the mystery of giant radio circles in space.

Astronomers have spotted ring-shaped structures known as odd radio circles that are so large they may contain entire galaxies. A team led by UC San Diego’s Alison Coil used simulations to show how outflowing galactic winds, possibly fueled by massive exploding stars known as supernovae, could blow vast shells of gas that expand into these strange rings. Published in a study last year, the work offers a new window into rare galactic processes and how galaxies grow and evolve.

9. UC San Diego researchers discovered ‘cool-burning flames’ in space in 2014

In experiments aboard the International Space Station, UC San Diego-led researchers ignited remotely fuel droplets and observed a type of flame that burns at much lower temperatures — so called “cool flames” that had been nearly impossible to study on Earth. These invisible flames still release energy, offering insights into combustion chemistry under unique microgravity conditions. The discovery could one day inform cleaner, more efficient engines, showing how space science can spark advances back on Earth. The tests were part of a decades-long collaboration between NASA and UC San Diego.

10. The Simons Observatory is opening a new window on the early universe.

What happened in the moments after the Big Bang? The answer may lie in the cosmic microwave background — faint radiation left behind from the universe’s earliest days. As a founding institution of the Simons Observatory in Chile’s Atacama Desert, UC San Diego scientists helped design and build the facility, which is already delivering some of the sharpest views ever of this ancient light. Their work is giving researchers new clues about how the cosmos began, how it evolved, and the mysterious forces that continue to shape it.

11. Our scientists are designing satellites that could transform how we see Earth from space.

What if we could see Earth’s frozen landscapes, forests and oceans in sharper detail from orbit than ever before? Two UC San Diego-led teams at Scripps Institution of Oceanography are now finalists in the NASA Earth System Explorers program, each awarded $5 million to refine new satellite mission concepts. One team, led by glaciologist Helen Amanda Fricker, is developing a satellite concept to map changes to glaciers, ice sheets and forest structures in 3D. Another, led by oceanographer Sarah Gille, is designing a satellite concept to measure global winds and ocean currents that drive weather and ocean circulation. If selected for full missions, each team would receive $310 million for development and launch — offering powerful new views of the Earth system from space.

12. UC San Diego faculty have helped shape NASA’s past and future.

When Sally Ride made history in 1983 as the first American woman in space, she inspired a generation to see the sky as no limit. After her NASA career, she joined UC San Diego’s physics faculty in 1989, where she advanced research in astrophysics and directed the University of California’s California Space Institute. Today, her legacy continues on campus through the Sally Ride Science Academy, which introduces students to vibrant role models in science, engineering and the arts, and through the Research Vessel Sally Ride, a state-of-the-art global class research vessel owned by the Office of Naval Research and operated by Scripps Oceanography. Carrying that torch into the present, Meenakshi Wadhwa joins UC San Diego as vice chancellor for marine sciences this month after serving as NASA’s principal scientist for the Mars Sample Return program — a mission that could deliver pieces of another world back to Earth for the first time.

13. Our engineers are helping explain how a piece of the moon could orbit near Earth

Astronomers have long wondered whether Kamo’oalewa, a tiny near-Earth asteroid, might actually be a fragment of the moon. In a 2023 study, a team that included Jacobs School of Engineering researchers ran computer models showing how a powerful meteorite impact could blast lunar material off the lunar surface — and in rare cases, fragments could settle into orbits like Kamo’oalewa’s. While the study doesn’t prove the asteroid’s origin, it shows a clear pathway for how moon fragments could become near-Earth asteroids, offering new insight into our planet’s cosmic neighborhood.