A supplement to Astronomy magazine MARS EXPLORING THE RED PLANET CONTENTS 2 A fresh look at Mars Seven spacecraft work to uncover Mars’ mysteries. 8 Curiosity’s latest findings from Mars Curiosity continues its mission of discovery on the Red Planet. 14 How moon dust will put a ring around Mars What will happen when Phobos is shredded into a ring? MARS: NASA, ESA, THE HUBBLE HERITAGE TEAM (STSCI/AURA), J. BELL (ASU), AND M. WOLFF (SPACE SCIENCE INSTITUTE); ROVER: NASA WWW.ASTRONOMY.COM 1 Fourth rock A fresh look at MARS ars— the latest interna- mineral-filled veins containing gypsum. Seven spacecraft — tional hotspot. Although Both substances provide further proof that designation might that groundwater and perhaps even sur- two on the ground seem a bit far-fetched, it face water once existed on this part of and five circling seems less so if you consider the seven Mars. The clays, in particular, suggest spacecraft now operating at the Red that some of this water could have been above — continue Planet and the five more being read- comparable to fresh water on Earth ied to go as scientific tourists. Robotic rather than the mildly acidic water to scour the Red emissaries from Earth have occupied inferred from Opportunity’s earlier Mars continuously since 1997, and the discoveries at Eagle, Endurance, and Planet for signs missions currently active date back to Victoria craters. 2001. This is the busiest, most fruitful, Even though Curiosity is the new kid of ancient water and most exciting time in the history on the block, having landed in August of Mars exploration. The armada of 2012, it surpassed its 1,000th sol in late and conditions spacecraft delivers a steady stream of May 2015. The sophisticated rover is data to planetary scientists that has led now exploring the lower slopes of Mount conducive to life. to important discoveries but also raised Sharp, the looming 3-mile-high (5km) intriguing new mysteries. mountain of layered sedimentary rocks by Jim Bell inside Gale Crater that drew the rover The ground truth team to this landing site. Mount Sharp’s Two rovers — Opportunity and Curi- layers record important parts of Mars’ osity — continue to return sensational early warmer and wetter history. Curi- scientific information from the surface. osity’s mission is to decipher that record Opportunity, which landed in January in detail, layer by layer if need be, to 2004 and celebrated its 4,000th martian learn as much as possible about the Red day, or sol (one sol equals about 1.03 Planet’s potential past habitability. Earth days), in April 2015, surpassed the Like its predecessors, Opportunity 26.219-mile (42.195 kilometers) distance and Spirit (which ceased transmissions of a marathon a month earlier. The rov- in March 2010), Curiosity has found and er’s science team, working on the planet’s continues to find ample evidence that surface virtually through the robot, is both surface and groundwater once now exploring the eroded rim of an flowed on Mars. Recently revealed signs ancient impact crater called Endeavour. of that water include swarms of mineral- NASA orbiters previously had rich veins created when moving ground- detected evidence for clay minerals water deposited materials that filled on the rim of this 14-mile-wide (22km) fractures in rocks. Other fresh discover- crater. Opportunity has sampled those ies of ancient water involve the detection clays and found abundant evidence for of the iron-oxide mineral hematite, NASA’s Curiosity rover poses for a selfie on Mount Sharp in January 2015. This vista combines dozens of images captured by a camera that sits at the end of the rover’s robotic arm. (Ground controllers posi- tioned the arm so it would be out of the mosaic’s frames.) The rim of Gale Crater appears at the top right of this image, and the peak of Mount Sharp is at the top left. NASA/JPL-CALTECH/MSSS © 2015 Kalmbach Publishing Co. This material may not be reproduced in any form without permission from the publisher. www.Astronomy.com WWW.ASTRONOMY.COM 3 Eagle Crater NASA’s Opportunity rover captured this pan- Endurance Crater orama from the rim of Endeavour Crater in Victoria Crater January 2015. The clay materials Opportunity Path of has found at Endeavour imply that ground- Opportunity water once existed in this area. NASA/JPL-CALTECH/ CORNELL UNIVERSITY/ARIZONA STATE UNIVERSITY Endeavour Crater Marathon Valley 5 km KELLIE JAEGER : 5 miles NASA/JPL-CALTECH/MSSS/NMMNHS; NASA/JPL-CALTECH/MSSS/NMMNHS; ASTRONOMY On March 24, 2015, Opportunity completed its first marathon when it passed the 26.219-mile (42.195 kilometers) mark on Mars’ surface. The journey took more than 11 years and carried the rover from its landing site in Eagle Crater to the rim of Endeavour Crater. It also has built up an impressive collec- The mission’s Context Camera has tion of chemical and mineral maps of the imaged more than 90 percent of the mar- surface that have helped scientists under- tian surface at a resolution of about 20 feet stand the distribution of ground ice as well (6m) per pixel. An even higher-resolution as new details about the planet’s geology camera, the High Resolution Imaging and mineralogy. Thanks to the mission’s Science Experiment, helps scientists study longevity, the Mars Odyssey team recently intricate details in small gullies apparently was able to complete a global set of infra- created by seeping water, identify fresh red geologic maps at a resolution of around impact craters formed within the past 330 feet (100 meters) per pixel. These are decade, and even spot alien spacecraft Curiosity continues to explore the layered rocks the highest-resolution maps of surface parts on the surface — most recently, the on Mount Sharp’s lower slopes. In September properties yet created for Mars and are likely wreckage from the 2003 crash of 2014, the rover drilled its first hole on the moun- Curiosity discovered these two-toned mineral veins on the lower slopes of Mount Sharp in March tain to collect samples for onboard analysis. The 2015. They apparently formed when water flowed through fractured rock and deposited minerals helping researchers differentiate bedrock ESA’s Beagle-2 lander. hole measures 0.63 inch (1.6 centimeters) across in the cracks. The veins appear as a network of ridges, each of which measures up to 2.5 inches from sediments and dust-covered surfaces. and 2.6 inches (6.7cm) deep. NASA/JPL-CALTECH/MSSS (6 centimeters) thick and half that in width. NASA/JPL-CALTECH/MSSS The second-oldest orbiter is ESA’s Mars The new arrivals Express, which went into an elliptical orbit Two rookies recently joined these three vet- formed when water alters basaltic volcanic between water and subsurface rock? Or around the planet in late 2003. The space- eran orbiters. ISRO’s Mars Orbiter Mission rock, and jarosite, an iron- and sulfur- could it be from some subsurface biological craft’s instruments have been mapping the (MOM), also called Mangalyaan, is India’s bearing mineral that can arise when volca- process? Although the latter seems unlikely, geology (in 3-D), mineralogy, and atmo- first interplanetary mission. And when it nic rock interacts with mildly acidic water. mission scientists don’t want to discount spheric chemistry of Mars during each entered Mars orbit in September 2014, that These kinds of mineral discoveries any possibilities until they perform addi- close pass ever since. They have discovered nation became the first to achieve success coupled with spectacular images of finely tional measurements and analyses. minerals that can form only in the pres- at the Red Planet on its first try. MOM’s layered sandstones and mudstones (fine- ence of water, vast amounts of water ice primary purpose is to test basic spacecraft grained sedimentary rocks that typically The view from above beneath the martian surface, and lava and instrument capabilities as well as ISRO’s form in water’s presence) are beginning to In the meantime, five active probes — three flows that might be only a few million ability to journey to Mars and operate suc- paint a clearer picture of Mount Sharp. from NASA, one from the European Space years old. The High Resolution Stereo cessfully from orbit there. But in the process ARIZONA OF NASA/JPL-CALTECH/UNIVERSITY Scientists now suspect it is an enormous Agency (ESA), and one from the Indian Camera continues to crank out spectacular of demonstrating these technologies and NASA’s Mars Reconnaissance Orbiter captured this impact crater, which formed in the past five accumulation of sediments deposited in an Space Research Organization (ISRO) — are topographic maps of volcanoes, craters, skills, the spacecraft has captured some years. This enhanced-color close-up reveals the ancient lake that periodically filled Gale plying the orbital seas above Mars. Using a and canyons across the planet. The 3-D stunning color photos of the martian sur- 100-foot-wide (30 meters) scar and debris that Crater early in the planet’s warmer and variety of sophisticated instruments, these images are helping scientists understand face and atmosphere from its highly ellipti- spreads up to 9 miles (15 kilometers) away. NASA/JPL-CALTECH/UNIVERSITY OF ARIZONA OF NASA/JPL-CALTECH/UNIVERSITY wetter history. It’s an exciting hypothesis, spacecraft are scouting the planet’s geology, the details of past geologic processes and cal orbit. The Mars Reconnaissance Orbiter captured Curiosity and its tracks as it trekked through but Curiosity needs to do a lot more climb- mineralogy, and atmospheric composition adding key information to the search for NASA’s newest artificial martian satellite layered deposits in April 2014.