THE PERSEVERANCE MARS ROVER: NASA’s Next Giant Leap in the Search for Signs of Life Beyond Earth Featured Story From the Desk of Lori Glaze Meeting Highlights News from Space Spotlight on Education In Memoriam Milestones New and Noteworthy Calendar LUNAR AND PLANETARY INFORMATION BULLETIN January 2021 Issue 163 FEATURED STORY About the author: Briony Horgan is an Associate Professor of Planetary Science at Purdue University. She is a Par- ticipating Scientist on NASA’s Mars Science Laboratory rover mission and a Co-Investigator on NASA’s upcoming Mars 2020 rover mission, the first step toward Mars sample return. Her research program uses data from NASA satellites and rovers, along with laboratory and field work back on Earth, to understand the surface processes that have shaped Mars and the Moon. THE PERSEVERANCE MARS ROVER: NASA’s Next Giant Leap in the Search for Signs of Life Beyond Earth Briony Horgan, Purdue University On February 18, 2021, the most ambitious Welcome to and orbiters have built a picture of mission to Mars yet will land on Mars: an Earth-like ancient Mars. Three to 4 the aptly named Perseverance rover. Jezero Crater billion years ago, Mars hosted vast river Perseverance will trek through ancient networks as long as the Mississippi, deep lake beds and river channels in Jezero On February 18, Perseverance will enter lakes that contained the building blocks Crater to search for signs of past microbial the martian atmosphere at 21,000 kilo- of life, and hot springs that bubbled with life on Mars preserved in the rocks. Along meters per hour (13,000 miles per hour), potential for life. These watery envi- the way, the rover will collect samples of and seven nerve-wracking minutes later, ronments were able to exist because martian rocks, regolith, and atmosphere. will be gently lowered onto the surface by ancient Mars had a thick atmosphere. These samples will be picked up by a a jetpack and tether combination known However, that atmosphere has been future mission and brought back to Earth, as the Sky Crane. The rover will land in leaking away, leaving the surface where laboratory scientists will scrutinize Jezero Crater, a site that NASA hopes will today cold, dry, and inhospitable. them for signs of life and clues to the provide a window to a time when rain history of Mars for decades to come. fell and rivers flowed on ancient Mars. After five years of debate, Jezero Crater was selected as the site on Mars that is The Perseverance rover on the Mars 2020 Over the past 30 years, a fleet of rovers most likely to preserve signs of life that mission is likely the best chance within our lifetimes for NASA to create a scientific revolution in astrobiology. Decades of Mars exploration have clearly shown that Mars has hosted a variety of environments with conditions suitable for life as we know it, and NASA has made the case that Jezero Crater in particular had the right combination of timing, geologic pro- cesses, and water chemistry to preserve signs of ancient microbial life, if it existed. This means that there is a chance that Perseverance will collect the sample from Mars that answers the question: “Are we alone in the universe?” This question is especially relevant right now. During the coronavirus pandemic, the mission has stayed on track in spite of disruptions Fig. 1. In a clean room at NASA’s Jet Propulsion Laboratory in Pasadena, California, engineers observed the first and delays, and we have been reminded driving test for NASA’s Mars 2020 rover on December 17, 2019. Credit: NASA/JPL-Caltech. that all life is vulnerable and precious. 2 Issue 163 January 2021 © Copyright 2021 Lunar and Planetary Institute FEATURED STORY beautifully preserved deltas; what makes a partial “bathtub ring” of mineral Jezero special is that it also contains deposits right at the elevations where unique mineral deposits. These minerals, the shorelines of an ancient lake might known as carbonates, provide a totally have reached. In a paper earlier this different mechanism for preserving life year, we suggested that these carbon- in an ancient lake in Jezero Crater. ates might have formed along ancient beaches as lake waters evaporated. Microbes: The Stromatolites can fossilize the microbial colonies that helped form them and even preserve textures of the microbes Fig. 2. Lighter colors represent higher elevation in this Original Beach Bums image of Jezero Crater on Mars, the landing site for themselves. Ancient stromatolites pre- NASA’s Mars 2020 mission. The oval indicates the Orbital spectrometers have shown that serve some of the earliest signs of life on landing ellipse, where the rover will be touching down carbonate is present throughout Jezero Earth, and Perseverance will search for on Mars. The color added to this image helps the crater Crater and in the watershed. On its similar signs of past life along the ancient rim stand out clearly, and makes it easier to spot the shoreline of a lake that dried up billions of years ago. own this is exciting since carbonates beaches of Jezero Crater on Mars. Scientists want to visit this shoreline because it may on Earth most commonly form due to have preserved fossilized microbial life, if any ever interactions between atmospheric carbon formed on Mars. Credit: NASA/JPL-Caltech/MSSS/ dioxide, rain, and rocks. That means JHU-APL/ESA. Perseverance: that carbonates on Mars might provide answers to important questions like A Robotic might have inhabited Mars billions of “How much rain fell on ancient Mars?” years ago, when microbial life was first Astrobiologist starting on Earth. Satellite images of However, the orbital data also show Jezero show a river leading into the crater that carbonates are particularly con- The payload that each Mars rover has and ending in a large delta, which must centrated around the inside edge of brought to the Red Planet has varied have formed in a long-lived ancient lake. Jezero Crater. The carbonates create depending on the kind of science the The Muddy Search for Organic Molecules The delta in Jezero is the first major target for Perseverance’s search for life. When a river flows into a body of water and slows down, the bigger particles like sand tend to drop out right away around the mouth of the river, creating deposits like sandbars. However, the smallest particles like mud and organic molecules tend to travel farther, creating thin layers at the bottom of the lake that can be pre- served underneath deltas as they build. On Earth, these muddy layers are one of the best places to look for concentrated organic molecules derived from life in the watershed and the lake itself. Using orbital data, scientists like Prof. Tim Goudge at the University of Texas–Austin have argued that these thin layers are exposed in the now eroded front of the Fig. 3. This image of Jezero Crater was taken by instruments on NASA’s Mars Reconnaissance Orbiter, which Jezero delta and could preserve signs regularly takes images of potential landing sites for future missions. Green indicates the presence of carbonates. On ancient Mars, water carved channels and transported sediments to form fans and deltas within lake basins. of ancient life in the lake and beyond. Examination of spectral data acquired from orbit show that some of these sediments have minerals that indicate chemical alteration by water. Here in Jezero Crater delta, sediments contain clays and carbonates. Credit: But other craters on Mars also contain NASA/JPL-Caltech/ASU. 3 Issue 163 January 2021 © Copyright 2021 Lunar and Planetary Institute FEATURED STORY evidence of microbial life is extremely difficult. Ultimately, we will need to look at samples from Jezero with advanced instruments on Earth. This is why Perseverance will also col- lect up to 38 pencil-sized rock cores that will be returned to Earth by a series of missions in the late 2020s. Paving the Way for Future Mars Exploration Perseverance will have many new capabilities that will transform how we explore Mars. The rover carries Ingenuity, a small helicopter that will be the first aircraft to fly on another planet. Because Mars’ atmosphere today is so thin — only 1% of Earth’s — Ingenuity has to be extremely lightweight [1.8 kilograms (4 pounds)] with very large blades [1.2 meters (4 feet) tip-to-tip] to get off the ground. Ingenuity will take Fig. 4. You may not be able to travel to Jezero Crater on Mars, but you can visit the next best thing: Lake Salda, images of the distant landscape and Turkey. Although it is located a world away, Lake Salda has mineralogy and geology similar to the dry martian help us scout the rover’s traverse; future lakebed. Credit: NASA Earth Observatory. Mars missions could adopt this model of rovers and aircraft working in tandem. mission aimed to achieve. Spirit and Perseverance will look a lot like Opportunity were robotic field geolo- Curiosity — the two rovers share the same Looking even further ahead, Perseverance gists, searching for signs of past water chassis and landing system. However, will help prepare for future human by looking at the surfaces of rocks with Perseverance has received a major missions to Mars. One of the many a hand lens and mineral identification overhaul under the hood in order to not challenges for astronauts will be the instruments. Curiosity is a roving geology only search for possible biosignatures but packing list for a two-year roundtrip laboratory analyzing the habitability to also place them in fine-scale context. journey, which includes air, water, and of these ancient watery environments Perseverance packs two Raman spectrom- rocket fuel to get home.