NASA’s Juno spacecraft launched Aug. 5, 2011 on a five-year journey slated to arrive at Jupiter on July 4, 2016.  The science goals of the mission are to study the giant planet’s interior structure, magnetic field, the composition of its clouds, and circulation of its atmosphere in order to better understand the evolution of the solar system.

The spacecraft’s JunoCam camera will offer the public the opportunity to participate in the mission’s science endeavors, said PSI Senior Scientist Candice Hansen, the lead scientist for JunoCam.

JunoCam has a 58-degree field of view, optimized for Juno’s unique views in its polar orbit of the pole of Jupiter – territory only seen obliquely by previous spacecraft.  Picture-taking opportunities are best in just a few hours before and after perijove – the closest point to Jupiter in Juno’s elliptical orbit.  Constraints on how much data volume can be stored and transmitted back to earth will put limits on the number of pictures that can be acquired. 

The JunoCam operations team will rely on the international community of amateur astronomers to supply up-to-date images of Jupiter’s ever-changing atmosphere to predict what atmospheric features will be in JunoCam’s images when they are acquired, she said.

“We are going to have the public help us decide which images we take, and when they will be taken,” Hansen said.

Once the data are returned to earth the public will be invited to process the raw image data and post their results.

On Aug. 26 the team powered JunoCam on for its first post-launch checkup.   An image of the Earth and moon from 6 million miles shows how far the spacecraft has already travelled on its epic mission.

Image credit: NASA/SWRI/MSSS

PSI Senior Scientist Catherine Weitz uses several data sets from the Mars Reconnaissance Orbiter (MRO) to study deposits laid down by water in Valles Marineris, the large canyon system on Mars.

One area of Valles Marineris is located at the far western end where linear troughs connect to rounded pits. This region, called Noctis Labyrinthus (Figure 1), has several troughs (small depressions) that contain hydrated minerals and layered sediments. These troughs could have been places for life to exist relatively recently in the planet’s history during the Late Hesperian to Early Amazonian time (2 to 3 billion years ago).

Figure 1: MOLA (Mars Observer Laser Altimeter) topographic view of Noctis Labyrinthus, Tharsis volcanoes, and western Valles Marineris region. Colors correspond to topography in kilometers. Inset shown in blue box is a blowup of the two troughs with study areas identified by red boxes. CTX (Context Camera) images overlain on THEMIS (Thermal Emission Imaging System) daytime IR mosaic. 

In a paper that just came out in the journal Geology, Weitz and her co-authors report finding many kinds of minerals that formed by water activity in two 30 to 40 kilometer long troughs at Noctis Labyrinthus, including clays that can only form by the alteration of other silicate minerals in the presence of non-acidic water.

Using high-resolution images from the High Resolution Imaging Science Experiment (HiRISE) camera and hyperspectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO) spacecraft, combined with Digital Terrain Models (DTMs) to determine elevations and view geometric relationships between units, the team was able to map hydrated minerals and understand how the water chemistry varied with time within each trough (Figure 2).

Figure 2: This picture of a depression on Mars in Noctis Labyrinthus shows a Digital Terrain Model (DTM) at five times vertical exaggeration produced from two stereo images taken by the High Resolution Imaging Science Experiment (HiRISE) camera. Approximately 350 meters of elevation are shown starting from the bottom of the trough. The colors represent different minerals detected using the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument. Several minerals are identified in the layered units, including clays and sulfates, and their stratigraphic relationships have been deciphered using the DTM.

Each trough probably experienced multiple episodes where water deposited and/or altered minerals. As each trough continued to enlarge and experience collapse over time, older minerals became buried and separated, followed by deposition of younger minerals, then finally erosion to re-expose buried units. Volcanism from the Tharsis volcanoes to the west may have created subsurface water that was subsequently transported through the ground and into the troughs. Localized volcanism that produced ash and gases, hydrothermal activity, and melting snow/ice within the troughs could have also produced some of the minerals. The observed minerals indicate water varied in pH levels over time, in one trough from acidic to neutral, and in the other trough from neutral to acidic and back to neutral.

Other occurrences of Fe/Mg-smectites have been found on Mars but almost exclusively in association with older, Noachian-age (more than 3.6 billion years ago) rocks, or produced by younger impact events. Following the deposition of Fe/Mg-smectites in the Noachian period, the climate on Mars is believed to have changed during the Hesperian time to favor formation of minerals under more acidic conditions, such as salts rich in sulfur (sulfates).

Weitz and her co-authors identified the same sulfates and Fe/Mg-smectites in the Noctis Labyrinthus troughs found elsewhere on Mars, but the progression of minerals over time, from sulfates to Fe/Mg-smectites, indicates a reverse order relative to what happened globally across Mars. Consequently, these two troughs are unique and could have been more habitable regions on Mars at a time when drier conditions dominated the surface.

PSI Associate Research Scientist Elizabeth Jensen has been studying a huge solar storm that caused large communications interference on Earth to demonstrate that polarized radio observations can increase warning times by a factor of 10.

In late October to early November 2003, the Sun released a number of energetic Coronal Mass Ejections (CMEs).  The Oct. 28 CME strongly affected the Earth causing a blackout in Sweden, occurrences of GPS outages, and high frequency radio communication interference (Gopalswamy, 2006).  As shown in the movie (http://youtu.be/JslClUHG_Ps), the CME was moving fast: approximately 2,000 kilometers per second.  This gave only 15 minutes for NASA’s Advanced Composition Explorer spacecraft in the upstream solar wind to measure the magnetic field orientation of the incoming storm.  This information is critical to determine the magnitude of the storm's negative effects on the Earth.

Prior to reaching the ACE spacecraft, only the technique of Faraday rotation can measure the magnetic field of the CME following its eruption and rotation into its final orientation in the solar wind (Jensen et al, 2010).  Here we show what the Faraday rotation signature of the CME would have looked like hours before impacting the Earth showing the left handed, southward oriented magnetic field axis.  This observation can provide an order of magnitude improvement in the warning time of determining the damage that can be incurred by an incoming CME.

This computer-generated image was made by overlaying Dawn framing camera data on a shape model of Vesta to give a three-dimensional perspective of its surface.  It covers a roughly 60 degree by 60 degree region of the surface, centered on the equator, showing a group of three prominent craters that has been nicknamed the "snowman" as well as a mysterious dark spot towards the left of the image.  The elevations are exaggerated by a factor of approximately two in order to better highlight Vesta's surface features.

The image was prepared by PSI Research Scientist David P. O'Brien using the publicly available POV-Ray software along with a Dawn framing camera image mosaic produced by DLR and a shape model of Vesta produced by PSI Senior Scientist Robert Gaskell.

For more information about the Dawn mission, go to http://www.nasa.gov/dawn

You are invited to delve into the wonders of impact craters on Earth on and other planetary bodies by visiting the Explorer's Guide to Impact Craters (EGIC) website that was conceived and developed by several PSI research scientists and is currently maintained by PSI Research Associate Frank Chuang. At the EGIC site – http://www.psi.edu/explorecraters – you can get the basics of impact cratering, take a virtual tour of an impact crater on Earth, see impact craters on the Earth, moon and Mars, and much more.

Panoramic view from the observation deck at Barringer (Meteor) Crater in northern Arizona (35.03 N, 111.02 W). Meteor Crater, formed approximately 50,000 years ago, is one of the best preserved and best exposed meteorite craters on Earth.

Panoramic view along the northwest rim of the Haughton Impact Structure on Devon Island, Canada (75.37 N, 89.68 W). This structure is located well above the Arctic Circle. Field conditions at Haughton can often be harsh with temperatures as low as -50 C (-58 F) with winds up to 70 km/h (44 mi/h).

Oblique aerial view of the Ries Impact Structure in southern Bavaria, Germany (48.88 N, 10.62 E). The structure, approximately 14.5 million years old, is located along the "Romantische Strasse," the Romantic Road between Frankfurt and Munich.

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has been providing scientists with data since it went into orbit around the planet closest to the Sun in March 2011. Planetary Science Institute researchers who are members of MESSENGER’s science team have been analyzing the data returned over the past four months to better understand the complex system that is the planet Mercury.

Figure 1. This area, not previously seen during the Mariner 10 and MESSENGER flybys of Mercury, was imaged by MESSENGER's narrow-angle camera (NAC) from orbit. The view includes contrasts in both albedo and terrain types. Smooth plains may be seen along the left edge, and a more rugged surface is evident to the right. A 23-km-diameter impact crater has exposed low-reflectance material (LRM) to the east, and patches of high-albedo material are visible to its west. For more images of Mercury's surface visit http://MESSENGER.jhuapl.edu Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

The different aspects of Mercury that are being studied by PSI scientists (Deborah Domingue, William Feldman, Robert Gaskell, Elizabeth Jensen, Catherine Johnson, and Faith Vilas) include its surface (Figure 1), its atmosphere (or exosphere), and the space environment around Mercury. The space environment includes such elements as the solar wind and photon flux (flow of particles and light), solar and galactic cosmic rays, and meteoroid bombardment. The interactions of these components of the space environment with the surface generate the observed exosphere and modify the physical, chemical, and mineralogical properties of the planet's rocky surface layer (regolith) (Figure 2).

Figure 2. This diagram summarizes the processes that result from interactions between the space environment and Mercury’s surface. These processes produce Mercury’s exosphere and weather the planet’s regolith. [From D. L. Domingue, P. L. Koehn, R. M. Killen, A. L. Sprague, M. Sarantos, A. Cheng, E. T. Bradley, W. E. McClintock, Space Science Reviews 131, 161 (2007).]

This modification or evolution of Mercury’s surface is commonly referred to as “space weathering.” Space weathering processes alter the spectral reflectance signatures (changes in reflected light with wavelength) of minerals by causing a surface to darken, introducing an increase in reflectance with increasing wavelength (a steeper spectral slope, also called "reddening"), and diminishing or removing spectral absorption features. Accounting for the effects of space weathering on measured spectral signatures is important in deciphering the mineralogical composition of Mercury’s surface. The minerals found in Mercury's crust give clues to the planet's geochemical evolution and bulk composition. The several hypotheses for Mercury's formation predict distinct crustal compositions. One of the prime objectives of the MESSENGER mission is to establish what planetary formational processes gave Mercury an iron core that occupies a much larger fraction of planetary mass than do the cores of the other inner planets. The resolution of this question provides insight into the processes operating during the formation of the inner solar system that produced the distinct compositions of the inner planets. It also provides guidance toward understanding the formational mechanisms for rocky planets around other stars. Knowledge of the different components of Mercury’s system, from its exosphere and space environment, its magnetic field and interior, to its crustal composition is a key part of the puzzle of the formation of the inner solar system and terrestrial planets. MESSENGER’s suite of science instruments was designed to address these questions.

          Deborah Domingue         William Feldman             Robert Gaskell              Elizabeth Jensen    

PSI Research Scientist Marc Fries is analyzing and interpreting Raman spectroscopy measurements of cometary materials collected by the NASA Stardust mission and returned to Earth. 

Upper left: The Stardust spacecraft encountered comet 81P/Wild-2 in January of 2004, collecting material from the comet by catching it in an aerogel collector grid. Upper right: Scientists examine the Stardust collector grid after it came to a soft landing in the Utah desert. Lower left: A cometary particle from the Stardust collector, carefully mounted and sliced to reveal its pristine interior. Lower right: A Raman spectroscopy image of the same particle showing the location of ancient carbonaceous material similar to that delivered to the young Earth.

PSI, in collaboration with The Citadel, is designing a training program for its astronaut operators of the Atsa Suborbital Observatory.  This began with a recent visit to the National AeroSpace Training and Research (NASTAR) Center outside Philadelphia, Pa., to undergo simulated spaceflights in a centrifuge, and learn about high-altitude physiology in a barometric chamber.

PSI Research Scientist Brent Garry experiences 3.55 Gs in an initial simulation in the NASTAR Center's centrifuge. Subsequent simulations exceeded 6 Gs. 

(L-R) Gregory Kennedy (NASTAR), Andrew Strasburger (Wofford College), Daniel Pittman (The Citadel), Ryan Boodee (The Citadel), Daniel Showers (Clemson University), Luke Sollitt  (PSI, The Citadel), Brent Garry (PSI), Mark Sykes (PSI), Melissa Lane (PSI) and Brienna Henwood (NASTAR).  

Video credit: NASTAR 

The NASA Dawn mission is now in orbit around the Vesta, the second largest body in the asteroid belt between Mars and Jupiter, and the mission’s first target. Dawn will be studying Vesta for a year before departing for its second target, the dwarf planet Ceres, at which it will arrive in 2015.

PSI is deeply involved with the Dawn mission and operates the Gamma Ray and Neutron Detector (GRaND), the instrument that will measure the elemental abundances of Vesta’s surface and constrain its mineralogical composition.

A rotating Vesta, which has an area the size of Arizona, is shown by linking together images taken over a five-hour plus period. The video shows deep grooves visible in the asteroid’s equatorial region.

The image above, taken 5,200 km from Vesta, shows great detail of the asteroid’s surface. The northern rotation axis is found in the upper left portion of the image and is in shadow. The heavily cratered surface reveals interesting features of  contrasting albedo and geology.

The southern hemisphere shows a peak on the right of the image that was first identified in Hubble images as the central peak of a giant impact structure covering the hemisphere.

PSI Members of the Dawn Science Team are:

Tom Prettyman           Bill Feldman            Mark Sykes   
Mission Co-I, GRaND PI                  Mission Co-I                        Mission Co-I       

Brent Garry             David O'Brien            Bob Reedy
Participating Scientist             Participating Scientist           Participating Scientist

Vesta Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

For more information about the Dawn mission, go to http://www.nasa.gov/dawn

PSI Research Scientist Marc Fries has developed a method of using weather radar imagery to identify and map meteorite falls. Below, meteorites are falling to the ground during the Park Forest meteorite fall on March 26, 2003. This event scattered meteorites across the Park Forest suburb of Chicago, with some meteorites striking houses and causing minor damage. Because weather radar data is archived, Marc is able to search for and construct fall imagery associated with eyewitness accounts of meteors.

Investigation of an alluvial fan complex in Harris Crater, Mars, led by PSI Senior Scientist Rebecca Williams, has revealed that material was deposited in multiple flows. The study adopted an interdisciplinary analysis of CTX, HiRISE, THEMIS, and CRISM data for the alluvial fan complex located on the northern rim of a Late Noachian-aged (~3.8 billion years ago) crater. Three distinct depositional units were identified based on surface attributes and thermophysical character. Most of the fan surface was deposited in water flows, but a small portion has attributes consistent with a late-stage, high sediment concentration flow, like a debris flow. This is the first example to document a transition in fluvial style on a Martian alluvial fan, recording a change in sediment supply and/or decline in water availability. Further details of the study are published in the journal Icarus (http://www.sciencedirect.com/science/article/pii/S0019103510003805).



Figure 1: Subscene of CTX image P14_006528_1583_XN_21S292W shows the morphology of the alluvial fan complex in Harris crater. The two alluvial fans have distinct apexes (black arrows) and source regions, separated by ~350 m ridgeline (white arrow). Most of the fan surface is defined by radiating ridges that originate at the fan apexes; these are interpreted as inverted distributary channels.



 

Figure 2. Thermal inertial values derived from nighttime THEMIS image I33675006 show subtle variations in thermal physical properties for the three surface units, with values consistent with coarser and/or cemented materials. Fan surfaces have elevated thermal inertia values (yellow) relative to the crater walls (blue, upper-left corner) without alluvial fans. A swath of material (outlined by arrows) has relatively depressed thermal inertia values (blue-green), and has a very different surface character with abundant boulders compared to the ridges on most of the surfaces of the alluvial fan complex. This swath is interpreted as a debris flow deposit.

Extrasolar planetary host stars are known to be chemically unusual. They are enriched in the key terrestrial planet building elements Iron, Magnesium and Silicon, along with other elements such as Carbon. This leads to the question: If the stars are enriched in these elements, what would any terrestrial planets be like? Would they also be enriched? Would they be chemically similar to Earth or be completely different?

The above schematic by PSI Postdoctoral Research Scientist Jade Bond shows the predicted bulk elemental planetary composition for simulated terrestrial extrasolar planets. The compositions range from being similar to Earth (HD 72659, top) to a mildly C-enriched version of Earth (Gl777, second from top) and even including C-dominated planets (HD19994, third from top). This shows that there is likely to be a wide variety of extrasolar terrestrial planets within known planetary systems. Earth and the habitable zone for all three systems are shown for reference.

PSI supports the Southern Arizona Regional Science and Engineering Fair (SARSEF), awarding its first "Solar System Exploration Awards" this year. These awards are for projects that demonstrate "insight into physical or astrobiological processes in the solar system or innovation in engineering design relevant to the exploration of the solar system or the expansion of human activity within it."

PSI’s top award went this year to Julia Nichols, a seventh grader at Doolen Middle School GATE program, for her investigation on finding Near Earth Objects, or NEOs (pictured here with her mother, Heather Reed and Mark Sykes, PSI CEO and director).

Luis Granado, a junior at Luz Academy, received PSI’s Honorable Mention award for his project titled  "Clash of the Comets" (pictured here with his parents Rosa and Robert Granado and Mark Sykes, PSI CEO and director).

An estimated 200 children learned about comets and participated in PSI's comet-making activities during Future Innovators Night at SARSEF (pictured here PSI’s Alan Fischer helps youngsters combine the ingredients that made up the comets the kids produced. Photo credit: Steve Metzger).

These images show a spiral pattern in the distribution of material emanating from the nucleus of comet 103P/Hartley 2.  The effective diameter of these images is 84,000 km compared to the 2 km long comet nucleus, so the nucleus, centered in these images, is too small to be seen. These enhanced images are one of many observations recorded in the fall of 2010 at the Kitt Peak National Observatory by PSI Senior Scientists Nalin Samarasinha and Beatrice Mueller and colleagues from the University of Maryland.

In these images, red denotes regions where cyanogen (CN) gas is more abundant. This spiral pattern suggests that there is a particular region on the nucleus of comet Hartley 2 that is emitting more CN gas than the rest of the nucleus – a “jet” – and that the nucleus is rotating clockwise.

A detailed analysis of the jet feature and its evolution over time indicates that unlike larger solar system bodies, which spin about one axis consistently, comet Hartley 2 is “tumbling,” or more technically, in a non-principal axis rotational state. The team could also measure the rate at which the comet’s rotation is decreasing. The nature and evolution of cometary spin states provide a window into the interior structure and evolution of comets.  The shape and the number of features seen in images like this provide information on the nature of comet surfaces.

The results from this study are published in the Astrophysical Journal Letters. This paper and a PSI Press release provide more detail.

The asteroid 2011 MD, about 10 meters in diameter, will fly by the earth on June 27. The animations below showing the geometry of this encounter were generated by PSI Research Scientist Pasquale Tricarico. It is interesting to note that this asteroid will come closer than the GPS satellites, and also that it comes from the northern hemisphere, passes over the Earth's south pole, and then is deflected so strongly by the gravity of the Earth that leaves the Earth back in the northern hemisphere.

The first animation shows the passage of the asteroid from an observer far away, on the same plane of the Earth's orbit (white line left of the Earth). The Sun is to the left. The asteroid 2011 MD comes in from the top right corner (night side of the Earth), has minimum approach distance close to the south pole, then leaves on the Earth's day side. Note how the orbit of the asteroid is perturbed by the Earth, so much to turn it around and send the asteroid almost back to where it comes from. 

The second animation is from the point of view of the asteroid, looking towards the center of the Earth. Notice how it comes within the constellation of GPS satellites, whose orbits are shown. Fortunately, no collision with a satellite is predicted.

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

The NASA Dawn mission is approaching its first rendezvous target, the asteroid Vesta at 2.2 AU from the Sun, revealing a very rugged topography and craters. Vesta is about the size of Arizona and has a surface covered with basaltic lava flows that have been pummeled over the age of the solar system. Vesta is one of a few surviving protoplanetary bodies in the asteroid belt between Mars and Jupiter. It grew to its current size, largely melted and formed a metallic core and rocky mantle - as did the Earth. It was nearly destroyed by a large impact forming a basin covering most of its southern hemisphere, which created a large family of ejected asteroids spanning the inner region of the main asteroid belt and reaching into near-Earth orbits. About 6% of all meteorites falling on the Earth today are thought to originate from Vesta.

Dawn will orbit and study Vesta for a year before leaving orbit and continuing its journey to the smallest planet, Ceres, also located in the asteroid belt. It will arrive at Ceres in February 2015. The Dawn website is at: http://dawn.jpl.nasa.gov/

The Navigation image shown was obtained on June 20 at a distance of 189,000 km (about half the distance between the Earth and Moon). The left shows a 60 minute movie of the asteroid rotating 67 degrees constructed from the original camera images showing individual pixels. On the right the images have been interpolated and sharpened.

PSI and Dawn: PSI scientists have been actively involved in the Dawn mission since its inception and include Co-Investigators Mark Sykes, Bill Feldman, and Tom Prettyman, and Participating Scientists Pasquale Tricarico, Aileen Yingst, David O'Brien, Bob Reedy, and Brent Garry. Tom Prettyman is Principal Investigator of the Gamma Ray and Neutron Detector. PSI Dawn Associates include Eric Palmer and Dan Berman.

The Dawn mission is managed by NASA's JetPropulsion Laboratory in Pasadena, Calif., for the agency's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. of Dulles, Va., designed and built the Dawn spacecraft. The framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany. The German Aerospace Center (DLR) Institute of Planetary Research in Berlin made significant contributions in coordination with the Institute of Computer and Communication Network Engineering in Braunschweig. The framing camera project is funded by the Max Planck Society, DLR and NASA. JPL is a division of the California Institute of Technology in Pasadena.