News Article | April 20, 2016
The Lunar Reconnaissance Orbiter (LRO) Wide Angle Camera (WAC) collects stereo observations by imaging the same area from different angles during many orbits. The apparent difference in positions of features when viewed Mark Robinson is a professor in ASU’s School of Earth and Space Exploration, LROC principal investigator, and a science team member on a number of missions including NEAR, CONTOUR, MESSENGER and Mars 2020. Robinson contributed this article to Space.com's Expert Voices: Op-Ed & Insights. The Lunar Reconnaissance Orbiter (LRO) was conceived and designed a decade ago to support a human return to the moon. That lofty goal required that the spacecraft produce a diverse set of measurements to provide high-resolution maps of potential landing sites, an assessment of potentially valuable lunar resources like water, and a deeper understanding of radiation hazards future astronauts will face. At that time, NASA requested proposals for instruments that could fill in existing knowledge gaps. In late 2004 after a competitive process, NASA selected seven science instruments for the LRO, including the Lunar Reconnaissance Orbiter Camera, commonly known as LROC (pronounced EL-rock). (See a gallery of the images at the Smithsonian National Air and Space Museum's LROC exhibition in Washington, D.C.) LROC is actually composed of three cameras: two identical Narrow Angle Cameras (NAC), and one Wide Angle Camera (WAC). The three cameras are controlled with a small electronics assembly known as the Sequence and Compressor System (SCS). The LROC hardware was all designed and built by Malin Space Science Systems (MSSS), located in San Diego. The original goals of the WAC were to map lighting conditions at the poles over a year and provide an accurate, global, lunar cartographic baseline. It also was to map out color differences due to compositional variation across the lunar globe, at moderate resolution. The original goals of the NAC were to investigate potential landing sites — both in terms of science return and engineering constraints — and to identify new impacts with before/after imaging (temporal imaging). Unraveling lunar science and resource questions and understanding where it is safe to land demand very high resolution — we chose 50 centimeter pixel scales. [Mapping the Moon ] The WAC acquires images in two ultraviolet colors (321 and 360 nanometers) and five visible colors (415 nm corresponding to violet-blue, 566 nm to green-yellow, 604 nm to orange, and 643 nm and 689 nm at the red end of the spectrum). The resolution is moderate, at 1,312 feet (400 meter) per pixel scale in the ultraviolet and 100 meter per pixel scale in the visible, from an altitude of 31 miles (50 kilometer). This softball-size camera maps the whole moon every month, in stereo. These observations are the foundation for extremely accurate new global maps , a necessary tool for future explorers. These maps include monochrome versions at high sun and low sun, and 7-color renderings. Each global map requires mosaicking together more than 10,000 individual WAC images, a complex task undertaken by the LROC team at the ASU Science Operations Center. Since the WAC field-of-view is 90 degrees, there is quite a bit of distortion, especially at the edges of the images — a meticulous inflight characterization of the camera distortion from thousands of images near the poles (looking at areas of overlap) allowed for a geometric correction precise to one-tenth of a pixel (or better). The geometric correction and very accurate spacecraft tracking results in maps that are accurate to better than a half pixel (164 feet, or 50 meters). A global WAC mosaic every month may seem repetitive or excessive. However, the data are not redundant — each month the lighting is different, so the WAC is building up the most comprehensive record of how varying light affects surface brightness ever acquired for any body in the solar system (outside of the Earth). We all have experienced how light varying over the course of a day drastically changes the look and feel of any scene. Many artists have taken advantage of this effect: think of Monet's Rouen Cathedral and water lilies series of paintings. In the case of the WAC, the lighting series has a more practical application: scientists can understand aspects of surface roughness and composition by documenting how the reflectance changes from sunrise to sunset. This translates not only to a better understanding of the lunar surface, but also to airless rocky bodies anywhere. Both lighting extremes are potentially valuable to future explorers. Permanent shadows are extremely cold (less than 40 kelvins; minus 388 degrees Fahrenheit) and likely harbor deposits of ice, which can provide water for future settlements. Areas in near-permanent illumination have stable temperatures and ready access to solar power. The repeat observations are more frequent near the poles, since LRO is in a low polar orbit it passes over each pole every 2 hours. From those passes, the LROC team created a time-lapse sequence showing regions that are in permanent shadow and other regions that are illuminated for extreme periods of time (such as mountain peaks near the poles). Finally, this small camera enabled a near global topographic map of the moon — with the exception of shadowed areas very near the poles — at a scale of 100 meters. The fine pixel scale is possible because the topography is measured many times at each pixel. Since the uncertainties in the measurements are mostly random we can take the average of many estimates (on average more than 80) at that one pixel and derive a precise estimate of the elevation. Despite its diminutive size, the WAC can certainly be considered the little camera that could! The heart of each NAC is a single row, or line array, of 4,996 imaging pixels. That's it, just one row of pixels. The NACs build up a complete 2D image by taking advantage of the 1,600 meter-per-second (50 cm per 0.34 millisecond) orbital velocity of the spacecraft. That single row of pixels is read out every 0.34 milliseconds 52,224 times (taking a total of about 18 seconds) to form a 4,996 by 52,224 pixel image. Each "readout" results in one line of the image. That works out to an impressive 249-megapixel image. This type of imaging scheme is sometimes called "push-broom." Since the NACs almost always image simultaneously and their fields-of-view overlap about 100 pixels, we actually obtain a 9,900 by 52,224 pixel image mosaic (498-megapixel image). Having two cameras also provides redundancy; if one failed we could still meet our requirements. The NAC images reveal startling detail; hardware and astronaut tracks are discernible at all six Apollo landing sites. Due to variations in spacecraft altitude (25 km to 220 km), the nadir- observing (looking straight down) NAC images have pixel scales ranging from 0.25 meters to 2.20 meters. In addition to the small pixel footprint, the NACs have an extended gray-scale dynamic range. Most digital cameras typically record only 256 shades of gray. The NAC records more than 3,200 shades of gray for each pixel, so it can fully capture subtle changes in bright and dark areas within the same image; a critical consideration because the lunar surface has very high contrast in many areas. The combination of small pixel scale and extended dynamic range of the NACs results in the beautiful images on display at the National Air and Space Museum and the LROC website (and more than a million other NAC images currently in the LROC archive). The LROC experiment is an overwhelming success. Its three cameras accomplished much more than the original objectives, and are still enabling groundbreaking science as it continues mapping the moon. a map of permanently shadowed regions, global topography, the first detailed ultraviolet map of the moon, and high-resolution maps and topography with startling ground coordinate accuracy. Scientific discoveries from the LROC images include new insights into the physics of impact- crater formation, discovery of very young volcanic features, confirmation that the moon is shrinking, discovery of silicic volcanoes, a new understanding of how light interacts with the surface and much more. However, the technical and scientific discoveries of LROC are not the subject of the National Air and Space Museum show. Rather, it is the revelation of the moon as a beautiful and engaging world in its own right that is the theme of this small collection of images. The lunar landscape can be dramatic, engaging, mysterious, wondrous, and at times, confusing. The whole character of a single landscape can appear foreboding, friendly or inspiring as the light changes through a lunar day. But in every case, the moon is seen as an alluring destination, somewhere I want to go and explore. It is my hope that the LROC images will reveal a moon that you never knew existed. There is no doubt in my mind that humans will someday return to the moon, and then move outward to Mars and beyond. The big questions are — by whom and when? Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Space.com. Explore the Moon (Virtually) with These Awesome Global Maps Copyright 2016 SPACE.com, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
News Article | October 12, 2016
Mars will face a huge dust storm in the coming months, according to a new study. The best part is that dust storms become more predictable, said the study, provided the next dust storm follows the pattern already evident from past data. Such early predictions would help greatly in preempting the damage to robotic rovers traversing the Red Planet and can check the future hazard to astronauts who may be putting up camps on the planet. Already scientists have traced a pattern in the occurrence of dust storms on the Red Planet. James Shirley, a planetary scientist at NASA's Jet Propulsion Laboratory said that the global dust storms on Mars are linked to the orbital motion of that planet. The study was published in the journal Icarus. He also said Mars momentum is influenced by other planets as it orbits the solar system's center of gravity. Based on previous data, a NASA statement predicted that Mars will "reach the midpoint of its current dust storm season" on Oct. 29. "Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date," Shirley said. The rise and fall of Mars momentum take place on a cycle of 2.2 years, which is higher than the average Martian year of 1.9 years. According to Shirley, global dust storms occur when the orbital momentum of Mars goes up. He added that no global dust storm had occurred in years when orbital momentum was declining, especially in the first half of the dust storm season. Shirley's paper also claimed close similarities between the present conditions in the dust storm season on Mars with those of the past. Now, scientists are watching the current data being collected from the Martian atmosphere to know whether the forecast will be proven right or wrong. On Mars, local dust storms are a common phenomenon. On many occasions, they grow in size to become strong regional systems when Mars gets closer to the sun during the southern spring and summer. Dust storms, in turn, create a haze that obscures the surface features. The most recent Martian global dust storm happened in 2007, which adversely hit two NASA Mars rovers — Spirit and Opportunity by hurting their solar power availability. "The global dust storm in 2007 was the first major threat to the rovers since landing," said John Callas, project manager for Spirit and Opportunity. All weather reports from Mars are handled by Malin Space Science Systems in San Diego. They base the data from the Mars Color Imager camera captured from NASA's Mars Reconnaissance Orbiter. According to the latest storm forecast, a series of local southern storms started in late August. Despite developing into a regional dust storm in September, it failed to pick up enough strength to turn into a global dust storm. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
James P.B.,Space Science Institute |
Thomas P.C.,Cornell University |
Malin M.C.,Malin Space Science Systems
Icarus | Year: 2010
We have used Mars Reconnaissance Orbiter data from 2007 and 2009 to compare summer behaviors of the seasonal and residual south polar caps of Mars in those two years. We find that the planet-encircling dust storm that occurred in the first of the two Mars years enhanced the loss of seasonal CO2 deposits relative to the second year but did not have a large effect on the continuing erosion of the pits and mesas within the residual cap materials. This suggests that the increase of bright frost in some regions of the residual cap observed between Mariner 9 and Viking can be accommodated within observed martian weather variability and does not require unknown processes or climate change. © 2010 Elsevier Inc.
News Article | October 6, 2016
Global dust storms on Mars could soon become more predictable -- which would be a boon for future astronauts there -- if the next one follows a pattern suggested by those in the past. A published prediction, based on this pattern, points to Mars experiencing a global dust storm in the next few months. "Mars will reach the midpoint of its current dust storm season on October 29th of this year. Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date," James Shirley, a planetary scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. Local dust storms occur frequently on Mars. These localized storms occasionally grow or coalesce to form regional systems, particularly during the southern spring and summer, when Mars is closest to the sun. On rare occasions, regional storms produce a dust haze that encircles the planet and obscures surface features beneath. A few of these events may become truly global storms, such as one in 1971 that greeted the first spacecraft to orbit Mars, NASA's Mariner 9. Discerning a predictable pattern for which Martian years will have planet-encircling or global storms has been a challenge. The most recent Martian global dust storm occurred in 2007, significantly diminishing solar power available to two NASA Mars rovers then active halfway around the planet from each other -- Spirit and Opportunity. "The global dust storm in 2007 was the first major threat to the rovers since landing," said JPL's John Callas, project manager for Spirit and Opportunity. "We had to take special measures to enable their survival for several weeks with little sunlight to keep them powered. Each rover powered up only a few minutes each day, enough to warm them up, then shut down to the next day without even communicating with Earth. For many days during the worst of the storm, the rovers were completely on their own." Dust storms also will present challenges for astronauts on the Red Planet. Although the force of the wind on Mars is not as strong as portrayed in an early scene in the movie "The Martian," dust lofted during storms could affect electronics and health, as well as the availability of solar energy. The Red Planet has been observed shrouded by planet-encircling dust nine times since 1924, with the five most recent planetary storms detected in 1977, 1982, 1994, 2001 and 2007. The actual number of such events is no doubt higher. In some of the years when no orbiter was observing Mars up close, Mars was poorly positioned for Earth-based telescopic detection of dust storms during the Martian season when global storms are most likely. Shirley's 2015 paper in the journal Icarus reported finding a pattern in the occurrence of global dust storms when he factored in a variable linked to the orbital motion of Mars. Other planets have an effect on the momentum of Mars as it orbits the solar system's center of gravity. This effect on momentum varies with a cycle time of about 2.2 years, which is longer than the time it takes Mars to complete each orbit: about 1.9 years. The relationship between these two cycles changes constantly. Shirley found that global dust storms tend to occur when the momentum is increasing during the first part of the dust storm season. None of the global dust storms in the historic record occurred in years when the momentum was decreasing during the first part of the dust storm season. The paper noted that conditions in the current Mars dust-storm season are very similar to those for a number of years when global storms occurred in the past. Observations of the Martian atmosphere over the next few months will test whether the forecast is correct. Researchers at Malin Space Science Systems, in San Diego, post Mars weather reports each week based on observations using the Mars Color Imager camera on NASA's Mars Reconnaissance Orbiter. A series of local southern-hemisphere storms in late August grew into a major regional dust storm in early September, but subsided by mid-month without becoming global. Researchers will be closely watching to see what happens with the next regional storm.
Cantor B.A.,Malin Space Science Systems |
James P.B.,Space Science Institute |
Calvin W.M.,University of Nevada, Reno
Icarus | Year: 2010
We used MGS-MOC and MRO-MARCI daily mapping images of the North Polar Region of Mars from 16 August 2005 (Ls=270°) to 21 May 2009 (Ls=270°), covering portions of three consecutive martian years (MY 27-MY 29), to observe the seasonal behavior of the polar ice cap and atmospheric phenomena. The rate of cap regression was similar in MY 28 and MY 29, but was advanced by 3.5° of Ls (~7-8sols) in MY 29. The spatial and temporal behaviors of dust and condensate clouds were similar in the two years and generally in accord with prior years. Dust storms (>100km2) were observed in all seasons, with peak activity occurring at Ls=10-20° from 50°N to 70°N and at Ls=135-140° from 70°N to 90°N. The most active quadrant was 0-90°W in MY 28, shifting to 180-270°W in MY 29. The majority of regional storms in both years developed in longitudes from 10°W to 60°W. During late summer the larger storms obscure the North Polar Region in a cloud of dust that transitions to north polar hood condensate clouds around autumnal equinox.Changes in the distribution of perennial ice deposits, especially in Olympia Planum, were observed between the 2. years, with the MY 29 ice distribution being the most extensive observed to date. Modeling suggests that the small, bright ice patches on the residual cap are not the result of slope or elevation effects. Rather we suggest that they are the result of local meteorological effects on ice deposition. The annual darkening and brightening of peripheral areas of the residual cap around summer solstice can be explained by the sublimation of a brighter frost layer revealing an underlying darker, ice rich layer that itself either sublimes to reveal brighter material below or acts as a cold trap, attracting condensation of water vapor that brightens the surface. An alternative explanation invokes transport and deposition of dust on the surface from the cap interior, and later removal of that dust. The decrease in cap albedo and accompanying increase in near surface atmospheric stability may be related to the annual minimum of polar storm activity near northern summer solstice. © 2010 Elsevier Inc.
Wolff M.J.,Space Science Institute |
Todd Clancy R.,Space Science Institute |
Goguen J.D.,Jet Propulsion Laboratory |
Malin M.C.,Malin Space Science Systems |
Cantor B.A.,Malin Space Science Systems
Icarus | Year: 2010
Observations by the Mars Color Imager (MARCI) on board the Mars Reconnaissance Orbiter (MRO) in two ultraviolet (UV, Bands 6 and 7; 258. nm, and 320. nm, respectively) and one visible (Band 1, 436. nm) channels of the 2007 planet encircling dust storm are combined with those made by the two Mars Exploration Rovers (MERs) to better characterize the single scattering albedo (ω0) of martian dust aerosols. Exploiting the low contrast of the surface in the UV (and blue) as well as the reduced importance of surface reflectance under very dusty conditions, we utilize the sampling of photometric angles by the MARCI cross-track geometry to synthesize an analog of the classical Emergence Phase Function (EPF). This so-called " pseudo-EPF" , used in conjunction with the " ground-truth" measurements provided by the MERs, is able to effectively isolate the effects of the dust ω0. The motivation for this approach is the elimination of a significant portion of the type of uncertainty involved in many previous radiative transfer analyses. Furthermore, we produce a self-consistent set of complex refractive indices (m=n+ik) through our use of an explicit microphysical representation of the aerosol scattering properties. Because of uncertainty in the exact size of the dust particles during the epoch of the observations, we consider two effective particle radii (reff) to cover the range anticipated from the literature: 1.6 and 1.8 μm. The resulting set of model-data comparisons, ω0, and m are presented along with an assessment of potential sources of error and uncertainty. Analysis of the Band 1 results is limited to ω0 as a " proof-of-concept" for our approach through a comparison to contemporaneous CRISM EPF results at 440. nm. The derived ω0 are: assuming reff=1.6μm-0.619-0.626,0.648, and 0.765, for Bands 6, 7, and 1, respectively; for reff=1.8μm-0.625-0.635,0.653,0.769, for the same band order. For either reff case, the total estimated error is 0.022, 0.019, and 0.010, again for Bands 6, 7, and 1. We briefly discuss our retrievals, including the asymmetry parameter (g) associated with our model phase functions, within the context of previous efforts, with an emphasis on the improved precision of our results compared to those in the literature. We also suggest several applications of our results, including an extension of the dust climatological record using MARCI Band 7 pseudo-EPFs outside of 2007 global dust event. Initial work on this particular application using a sample of 135 pseudo-EPFs near the MERs suggests that optical depth retrievals with a precision in the range 0.2-0.4 may be possible under moderate loading conditions (i.e., τ<1.5). © 2010 Elsevier Inc.
News Article | December 14, 2015
For the first time ever, the Curiosity rover has studied the ripple surface of a Martian sand dune. The probe was over a section of Mars' "Bagnold Dunes," whose field sits along the northwest flank of Mount Sharp. The amazing pictures were snapped on November 27. NASA says the scene was splashed with color adjustment to approximate white balancing to resemble how the sand dunes would look under daytime conditions on Earth. NASA says the San Diego-based Malin Space Science Systems built and operate the Mastcam aboard the Curiosity. Meanwhile, NASA's Jet Propulsion Laboratory, of the California Institute of Technology, created the Curiosity rover and manages NASA's Science Mission Directorate in Washington. One scintillating image shows a zoomed-in view of an undisturbed field of Martian sand. The image is so pristine that its one could make out the rough grains of the sand just upon a mere glance. Another shot clearly shows the Curiosity's tire tread marks in the sand with the ripples proving that the sand on Mars is loose. Yet another image reinforces that notion, as it actually shows a crack in the sand with loose grains flaking off. NASA describes it as a: "disturbance by the wheel exposed interior material of the sand body, including finer sand grains than on the undisturbed surface. Sunlight is coming from the left." Perhaps the most beautiful and even telling picture of them all, though, is this long shot, showing rows and rows of distinctively-shaped sand dunes.
Daubar I.J.,University of Arizona |
McEwen A.S.,University of Arizona |
Byrne S.,University of Arizona |
Kennedy M.R.,Malin Space Science Systems |
Ivanov B.,Russian Academy of Sciences
Icarus | Year: 2013
The discovery of 248 dated impact sites known to have formed within the last few decades allows us to refine the current cratering rate and slope of the production function at Mars. We use a subset of 44 of these new craters that were imaged before and after impact by Mars Reconnaissance Orbiter's Context Camera - a thoroughly searched data set that minimizes biases from variable image resolutions. We find the current impact rate is 1.65×10-6 craters with an effective diameter ≥3.9m/km2/yr, with a differential slope (power-law exponent) of -2.45±0.36. This results in model ages that are factors of three to five below the Hartmann (Hartmann, W.K. . Icarus 174, 294-320) and Neukum et al. (Neukum, G., Ivanov, B.A., Hartmann, W.K. . Space Sci. Rev. 96, 55-86)/Ivanov (Ivanov, B.A. . Space Sci. Rev. 96, 87-104) model production functions where they overlap in diameter. The best-fit production function we measure has a shallower slope than model functions at these sizes, but model function slopes are within the statistical errors. More than half of the impacts in this size range form clusters, which is another reason to use caution when estimating surface ages using craters smaller than ~50m in diameter. © 2013 Elsevier Inc.
Shean D.E.,Malin Space Science Systems
Geophysical Research Letters | Year: 2010
The floors and walls of many mid-latitude (∼30-60) craters on Mars appear to be mantled by relatively young material(s) with distinct morphology and erosional properties. Collectively, this material ("fill") is often interpreted as ice-rich, with emplacement and modification related to climatological processes. Here, I document material and associated landforms within 38 craters between 4-13S in the Sinus Sabaeus region that appear morphologically similar to material and landforms within mid-latitude craters. These equatorial/mid-latitude materials may also share a common composition and emplacement mechanism. Near-surface ice is unstable at equatorial latitudes under present conditions, suggesting that emplacement could have occurred under different climate conditions in the past. High-obliquity (35-45) general circulation model (GCM) simulations show surface ice accumulation in Sinus Sabaeus and Tharsis, where similar material and landforms have been documented. These observations are consistent with the hypothesis that past obliquity-driven climate change resulted in equatorward volatile migration on Mars. © 2010 by the American Geophysical Union.
News Article | December 21, 2016
Update: The story below will apear in the 23 December issue of Science, but after the magazine went to press, the Japan-based team Hakuto announced that it had also booked a ride to the moon—along with a rival, Team Indus. The lander of the India-based team can carry 20 kilograms and so, in addition to its own rover, Team Indus will also carry Hakuto’s 4-kilogram rover. It remains to be seen which rover will get out of the lander first and set off on the 500-meter trek required to win the prize. A few years back, Oded Aharonson, a planetary scientist at the Weizmann Institute of Science in Rehovot, Israel, met three space-mad engineers who were building a cut-price mission to the moon. Backed by a mix of companies, foundations, and universities, the trio was competing for the $20 million jackpot of the Google Lunar XPrize, which challenged privately funded teams to be the first to land on the moon, travel 500 meters, and send back pictures and video. Other than that, the engineers' ambitions didn't extend beyond a triumphant party in the central square of Tel Aviv, Israel. But to Aharonson, this was too good an opportunity to miss. "You have to do something more. There must be some intellectual legacy to this mission," he told them. After several such conversations, he says, "they bought it." The party plans are still on. But SpaceIL now has a mission scientist—Aharonson—and its lander will carry a lightweight sensor to map the moon's magnetic field. Science was never the primary driver for the Lunar XPrize, which reaches a major milestone at the end of this month. Only those teams with a contract to launch their spacecraft before the end of 2017 will be allowed to stay in the competition. Of the 16 industry teams still in the running, the XPrize authorities have confirmed launches for just four, including SpaceIL. A fifth team, Part-Time Scientists, a Germany-based team founded by researchers who initially entered the prize alongside their day jobs, is still awaiting confirmation of its launch booking. Engineering will determine the ultimate winner of the prize, which is modeled on the Ansari XPrize, awarded in 2004 to give a leg up to cheap human spaceflight. The race to get to the moon, move around, and report back home is meant to foster cheap lunar access so that industry and government agencies can prospect for minerals or build resorts for space tourists. Along the way, though, science will benefit, says Andrew Barton, the prize's director of technical operations in Culver City, California. Movement over the surface and communication with Earth are basic technologies for many future science missions. Also, he notes, the competition offers two bonus prizes that are at least partly scientific. The water discovery bonus ($4 million) requires teams to unambiguously detect water on the surface and publish a peer-reviewed paper to prove it. "Water has been observed from orbit but no one has yet made a physical measurement on the surface," Barton says. For the Apollo Heritage Bonus Prize ($4 million), teams must broadcast video and pictures from one of the Apollo landing sites, and Barton says data on how exposure on the moon has weathered the Apollo artifacts could have scientific value. None of the potential finalists has declared an intention to look for water. That may be because they're most likely to find it in permanently shady craters at the poles, a difficult place for solar-powered rovers to reach. Nor is it easy to get a look at Apollo relics. Landing on the moon is imprecise, so the nearest Apollo site could lie far beyond the range of the teams' modest rovers. Closer landings risk damage to sites of historical importance, from the blast of a retrorocket or a collision. Part-Time Scientists, however, is planning to try. The team believes its rovers—developed with the help of the Audi car company—have the necessary range. Karsten Becker, the team's chief technology officer for electronics, says they want to get up close to Apollo 17's lunar rover, which is made of materials including aluminum, fiberglass, nylon, and duct tape. "What's happened to that after 45 years in the space environment? Is it like new or in shreds from micrometeoroids?" he asks. Team Indus from India may go for a smaller, $1 million bonus by visiting the site of an unmanned landing—China's Chang'e 3 lander and Yutu rover, which operated from 2013 to 2014. Although the bonus prizes haven't generated a stampede to do science, most of the finalists have taken on one or several experiments. SpaceIL's magnetometer aims to help answer the question of where the moon's magnetic field comes from. Is it the relic of an ancient field, created by a churning iron core like Earth's, that was locked into its surface rocks when the core solidified? Or does it come from iron-rich asteroids that generate magnetic fields from the energy of their impact? As the Israeli craft orbits the moon and moves across the surface, the magnetometer will look for correlations between magnetic field changes and impact sites. "This mission may not settle the question once and for all, but we'll make progress," Aharonson says. Another finalist, Team Indus, is holding an open competition for young people aged 25 and under to devise experiments that could point a way to sustainable settlements on the moon. The team was overwhelmed by 3000 entries from all over the world, including plant and microbial growth experiments, proposals to build lunar structures and radiation shields, and even an attempt to brew beer on the moon. The team recently narrowed the field to a short list of 25, and those groups are now building prototypes that must be the size of a soda can and weigh less than 250 grams. In March 2017, up to eight experiments will be chosen to fly. Moon Express is carrying a couple payloads: laser retroreflectors from a U.S.-Italian university group to precisely measure the Earth-moon distance for gravitational studies, and a 7-centimeter optical telescope for the International Lunar Observatory Association, a nonprofit aiming to show the power of observing in airless, ever-clear skies. The telescope will have open access for "citizen scientists." Synergy Moon, an international team with offices in San Francisco, California, aims to blend the arts and sciences—perhaps with a holographic projector that will display artworks on the moon. The team claims it will study weathering of the lunar surface and the nature of the thin atmosphere above it using tiny autonomous robots they call lunar spiders and butterflies. These may be more artwork than instrument, according to a team blog post: "They will also be programmed for swarm behavior, to create random geometric and color patterns." In general, it's best not to expect major payoffs for science, says Mike Ravine, a project manager at Malin Space Science Systems in San Diego, California, which builds instruments for NASA Mars missions. In 2000, Ravine attempted to get a private moonshot off the ground with BlastOff! Corporation. The effort failed, but it taught him the challenge of trying to do science on a cut-rate mission. If the XPrize teams succeed, he says, "it would be great to wring some scientific value out of it. But it's a pretty high bar."