Planetary Analog Explorer

Near Medicine Lake Volcano in California, scientists explore lava caves from both inside and out, working towards a future in which astronauts will be able to detect hidden caves from above ground. These images are not to scale; the opening in the Moon’s surface measures 65 meters (213 feet) across. Credits: NASA/Ernie Bell (left), NASA/Arizona State University (right)

On the slopes of Hawaiʻi’s Kilauea Volcano, researchers use aerial cameras and hand-held science instruments to characterize their surroundings. Their goal: to determine how long it would take a small team of geologists and astronauts to perform the same kinds of tasks in a different volcanically-formed environment, like the lunar surface. Future crews will draw on lessons learned from both modern mission simulation at sites on Earth and the Apollo missions. (Shown here: An Apollo 15 astronaut at work near Hadley Rille on the Moon.) Credits: NASA/Andrea Jones (left), NASA (right)

The salts found in Utah's Pilot Valley are exceptional and ordinary at the same time. Perchlorate, a salt that stores energy so well it’s used as an ingredient in solid rocket fuel, has been observed in many places on Mars. (Shown here: the Martian northern plains.) On Earth, tiny life forms use this same kind of salt as an energy source. Recent data suggests that perchlorate is common throughout our solar system, including on ocean worlds like Jupiter's moon Europa. If microbial life exists beyond our planet, or if it ever did in the past, knowledge of these salts may someday help scientists to recognize it. Note on scale: The solar panel array in the Mars image is part of NASA's Phoenix lander and is about the size of a large dinner table. Credits: Courtesy of Dr. Kennda Lynch (left), NASA/JPL-Caltech/U Arizona (right)

Alaska’s Gulkana Glacier and Saturn's moon Enceladus have secrets in common: liquid water concealed by a thick layer of dirty, rocky ice. Icequake-detecting experiments at Gulkana Glacier lay the groundwork for future measurements on Enceladus – but no lander has yet touched down on that frozen world. This image of Enceladus was taken from about 14,000 kilometers (9,000 miles) away. Its scale is 81 meters (267 feet) per pixel.  Credits: NASA/Nick Schmerr (left), NASA/JPL/Space Science Institute (right)

Description: Chile’s Atacama Desert, one of the driest places on Earth, helps us to understand how the building blocks of life might respond to Martian conditions over time. The science instruments in this truck can detect very small amounts of target molecules in the sun-baked soil. Robotic explorers like NASA’s Perseverance Rover, shown here with rotorcraft Ingenuity in the background, use their own portable lab instruments to search for biosignatures on Mars. Note on scale: Perseverance is slightly taller than the human researchers, and Ingenuity is just nineteen inches tall. Credits: NASA/Marco Castillo (left), NASA/JPL-Caltech/MSSS (right)

Researchers in Iceland’s Vikursundar region, at the foot of Askja volcano, survey and monitor large ripples in the landscape’s gravelly surface (left). These ripples are sluggish, moving only under the most extreme weather conditions. Year after year, the team uses science instruments mounted on small drones to capture digital terrain models of the landscape, revealing changes over time. Mars, too, has slow-moving land ripples (right).  Note on scale: The Martian ridges shown in this Mars Reconnaissance Orbiter image are ten times the size of the ones in Iceland. The field of view on the left is 300 meters or 1000 feet wide, compared to three kilometers (almost two miles) on the right. Credits: NASA/Stephen Scheidt (left), NASA/JPL/University of Arizona (right)

Description: The Viking landers were the first to return images from the Martian surface, but the views they sent home were familiar. Utopia Planitia, as seen by Viking 2, looks a lot like Death Valley National Park. It’s no coincidence that NASA’s Mars 2020 team practiced hazard avoidance here before sending Perseverance and Ingenuity on their way to Mars. Credits: NASA/Andrea Jones (left), NASA/JPL/Caltech (right)

The light-colored sediments seen at the edge of Lake Salda, in Turkey, may have formed with the help of tiny living things. In Jezero Crater, a place on Mars that has geological and mineral characteristics in common with Lake Salda, NASA's Perseverance Rover is searching for similar signs of ancient life. Evidence of a former river flow along Jezero’s rim suggests that this crater was once a vast lakebed. Images not to scale; Lake Salda is similar in size to the oval-shaped landing area, shown here, that Perseverance targeted for landing. Credits: NASA/USGS (left), NASA/JPL-Caltech/MSSS/JHU-APL/Purdue/USGS (right)

Shield volcanoes like Sif Mons, the low mountain near the right-hand horizon in this computer-generated image of Venus, are common on planets and moons throughout our solar system. Planetary volcanologists test scientific hypotheses about how volcanoes form at sites like Aden Crater, a shield volcano in New Mexico. Note on scale: The two prominent Venusian mountains shown here are about 750 kilometers, or 453 miles, apart. Credits: NASA/Lora Bleacher (left), NASA/JPL (right)

In Arizona’s Verde Valley, scientists use field and lab research to learn how signs of life, or biosignatures, are preserved. This kind of work helps robotic explorers like NASA’s Curiosity rover, shown here at the base of Mount Sharp, know what to look for on Mars – and helps the researchers back home to understand what they find. Note on scale: the Curiosity rover is about the same size as a large SUV. Credits: NASA/Svetlana Shkolyar (left), NASA/JPL-Caltech/MSSS (right)

Scientists use ground-penetrating radar to find buried ice near Askja volcano in Iceland. The same technology will help future lunar explorers to detect water ice beneath the lunar surface in permanently shadowed regions near the lunar South Pole. Humans have not yet set foot on this part of the Moon, and even if there were astronauts in this view, they would be much too small to see. The large crater near the center of this image is about 100 kilometers (62 miles) wide. Credits: NASA/Cherie Achilles (left), NASA (right)