Caltech's 2026 Space Challenge Visits a Comet and Venus

The Caltech Space Challenge (CSC) returned to campus March 23–27 after a four-year hiatus, bringing together 32 graduate students from around the world to design a dual-target space mission to visit Venus and a nearby comet.

Despite being Earth's nearest twin in size and composition, Venus evolved into a world of crushing pressure and extreme heat. Understanding why remains one of planetary science's most pressing questions. Both NASA and the European Space Agency are developing missions to Venus, making it a timely and relevant target for this year's challenge.

The challenge, titled "A Journey Through Blaze and Frost," required teams to design a mission to visit and study not only Venus but also a nearby Halley-type comet. Halley-type comets, named after the well-known Halley's Comet, have elliptical orbits that bring them into the solar system for only a short period of time. As frozen relics of the early solar system, comets preserve organic molecules and ices that date back to their formation.

Split evenly into two teams, Team Voyager and Team Explorer, contestants were selected from an extremely competitive pool of more than 500 applicants worldwide. Under the mentorship of experts from campus and JPL, which Caltech manages for NASA, the teams spent the week wrestling with the engineering challenge of building a single spacecraft capable of meeting the two very different scientific objectives. Their spacecraft concepts aimed to characterize the comet's physical and chemical environment while also probing the chemicals, dust, and solar wind in the vicinity of Venus.

The 2026 Space Challenge was the first since 2022, in which two teams were challenged to design an autonomous mission to collect and return samples from Saturn's moon Titan.

This year's challenge was co-organized by Caltech graduate students Federico Benazzo (MS '23) and Jennifer Berry (MS '24).

"I was really excited to organize the Space Challenge because of its impact on the participating students," Benazzo says. "Everyone always feels extremely rewarded by the end, and the connections they form throughout the week are long-lasting. As co-chair, I oversaw every aspect of the competition, and, in particular, the most difficult aspects included securing sponsorship and ensuring the students could visit JPL."

The contestants worked diligently during the week, attempting to maximize scientific information gained while keeping the whole project within a feasible budget.

Mattia Tagliente from Polytechnic University of Bari, a contestant from Team Explorer, said the hardest part was designing a spacecraft capable of serving two completely different scientific objectives. "The comet and Venus demand very different things from your spacecraft, so you are always asking yourself: How do we do both and do both well?"

"For me, the most rewarding part was experiencing how quickly a group of strangers from around the world became a team," Berry says. "It's a hectic week, but within a day or so they're making complex mission decisions, challenging each other's ideas, and building something far beyond what we could've hoped. That intensity and collaboration are what make the experience so incredible."

Team Voyager ultimately took top honors for its mission concept, which used a spectroscopic instrument dubbed SEAHORSE (Spectroscopy for Escape of Venusian Atmosphere and Hydrogen Outgassing in Retrograde SWAN Encounter) to simultaneously study volatile gases escaping from the Venusian atmosphere and hydrogen outgassing from the comet during a retrograde flyby. This innovative approach would give scientists a simultaneous look at volatile loss across two very different planetary environments.

The week culminated in final presentations at Guggenheim Auditorium, where Team Voyager and Team Explorer each made their case before a panel of four judges: Mike Watkins, professor of aerospace and geophysics and director and Allen V. C. Davis and Lenabelle Davis Leadership Chair of the Keck Institute for Space Studies (KISS); Fred Hadaegh, research professor in aerospace at Caltech; JPL principal scientist Carol Raymond; and former NASA astronaut Garrett Reisman (PhD '97).

During the presentations, the students detailed the engineering decisions behind their mission plans. A closing ceremony at the Athenaeum followed, at which Team Voyager was recognized for delivering the most complete presentation and most cohesive mission concept. After the ceremony, participants joined Space Challenge mentor Nigel Angold of Princeton University, whose experience includes operations management for NASA and European Space Agency missions, and who has served as a mentor for every iteration of the Caltech Space Challenge since its inception in 2011—for a celebratory evening at Lucky Baldwin's, organized and sponsored by KISS.

According to Tom Prince, the Caltech Ira S. Bowen Professor of Physics, Emeritus, and former KISS director, the Caltech Space Challenge "will have a lasting legacy by helping to develop the next generation of space explorers."