Clues like Martian riverbeds, polar ice caps, and subterranean lakes have convinced Scott Hubbard that water in the geology of the red planet offers evidence that Mars holds possibilities for life.
In “Exploring Mars: Following the Water,” Hubbard gave a synopsis of Martian missions, focusing on the evidence of water’s past and present in the 2026 John R. and Donna S. Hall Engineering Lecture April 7. Hubbard, BS’70, majoring in physics and astronomy, is author of “Exploring Mars: Chronicles from a Decade of Discovery.”
Hubbard, a professor at Stanford University and former director of NASA’s Ames Research Center, is widely known as NASA’s former “Mars Czar” for his leadership in transforming and advancing the agency’s Mars exploration program as the first-ever Mars Program Director. He is a prominent voice on the future of human missions to Mars.
As director, he began restructuring the program after the 1999 loss of Mars Climate Orbiter and Mars Polar Lander, leading to the success of subsequent missions. Hubbard is credited with establishing the “follow the water” strategy, which became the guiding scientific principle for Mars missions like the Mars Pathfinder and Spirit (2003-2010) and Opportunity (2003-2018) rovers.
The twin exploration rovers launched in 2003 and landed in 2004 and according to ‘success criteria’ were supposed to last only a few months. “Spirit lasted 7 years and Opportunity lasted 14 years,” Hubbard said.
“The Curiosity rover (2011) gave us breakthrough discoveries of water and organic compounds on Mars. These were extraordinary findings,” he said. “Organic structures started to show up, giving us biosignatures of ancient life and that Mars is more diverse than we thought and modern life is possible.”
“In the past there was abundant water. In the present, Mars is dry and dead. In the future, could we establish a base there?” Hubbard asked.
NASA’s Perseverance rover (nicknamed “Percy”) is currently collecting and caching rock samples on Mars that are designed for future return to Earth. Launched in 2020 and landing in February 2021, the rover drills core samples, seals them in tubes, and either stores them onboard or deposits them at a “Three Forks” sample depot.
NASA’s ambitious Mars Sample Return (MSR) program has been effectively cancelled following a U.S. Congress budget decision in early 2026 that eliminated funding for the current design. Although the MSR program is in a state of restructuring and paused, NASA is aiming for a new, more affordable approach to return samples by the 2030s.
Hubbard is hopeful that MSR will return to a mission queue. “Returning Martian samples to Earth could redefine our place in the universe.”