Press Releases
- Dawn Spacecraft Offers First Look at Giant Asteroid’s Chemistry
- Solstice Event Saturday Begins Educational Collaboration Between Planetary Science Institute and Children’s Museum Tucson
- Mars Science Laboratory to Offer New Scientific Insights
- PSI researcher’s 20th Children’s Science Book is Published
- Young Clays on Mars Could Have Been Habitable Regions for Life
- NASA Grant Funds Research on Jupiter Plasma Ring "Energy Crisis"
- Juno Mission Will Open Jupiter Up to the PUblic
- Atsa Suborbital Observatory Team Completes First Training
- Planetary Science Institute Selects XCOR to Fly Atsa Suborbital Observatory
- MESSENGER’s Data Offers Insights on Inner Planet
- Small Mass of Mars Could be Due to Planetary Orbital Migration
- Researchers gain new insights into Comet Hartley 2
- Northern Mars Landscape Actively Changing
Dawn Spacecraft Offers First Look at Giant Asteroid’s Chemistry
Jan. 19, 2012, Tucson, Ariz. – The NASA Dawn spacecraft’s close-up study of the giant asteroid Vesta is offering researchers their first look at the elemental composition of this ancient protoplanet. Vesta is the second most massive body in the main asteroid belt and has remained intact since its formation more than 4.5 billion years ago. Dawn’s Gamma Ray and Neutron Detector (GRaND) will determine the chemical composition of Vesta, providing new information about how Vesta formed and evolved. Tom Prettyman, a Senior Scientist at the Planetary Science Institute, is the lead for GRaND as well as Dawn’s Geochemistry Team.
The NASA Dawn spacecraft has been acquiring science data in orbit around Vesta since July of 2011. In December, Dawn reached its lowest altitude orbit, with an average distance of about 130 miles from Vesta’s surface. Vesta’s diameter is about 330 miles, just a little bit larger than the width of Arizona. Dawn plans to stay in this orbit for 110 days before ascending to higher altitudes and departing to its next destination, the dwarf planet Ceres.
At low altitudes, GRaND is detecting strong neutron and gamma ray signals that we will analyze to map the elemental composition of the entire surface of Vesta, Prettyman said. Unlike Dawn’s framing camera and visible and infrared mapping spectrometer, GRaND can see in the dark, Prettyman added. Consequently, GRaND is sensitive to the composition of Vesta’s surface at high northern latitudes, presently in polar night.
GRaND measures the abundance of elements found in planetary surfaces, such as hydrogen (H), iron (Fe), magnesium (Mg) and silicon (Si). The data will help scientists determine how hydrogen was delivered to the surface of Vesta – for example, by the solar wind or by carbon-rich materials hitting the asteroid. Measurements of rock-forming elements, including Fe, Mg, and Si, will help them understand the volcanic processes that shaped Vesta.
After five weeks of mapping in the spacecraft’s low altitude orbit, global-scale variations in Vesta’s elemental composition are apparent, Prettyman said. Vesta’s varied surface distinguishes it from smaller asteroids, which are typically uniform in composition. Vesta, which underwent complex geochemical processes, forming a core, mantle, and crust, seems more like a terrestrial planet than an asteroid.
GRaND’s initial observations are tantalizing; however, their interpretation will require additional accumulation of data and further analysis by Dawn’s Geochemistry Team. First results will be reported soon after mapping at low altitudes is complete.
Prettyman is lead author of a paper titled “Dawn’s Gamma Ray and Neutron Detector,” published recently in the journal Space Science Reviews as a chapter in a book about the Dawn Mission. The paper provides a detailed description of GRaND, including science objectives, design and construction, and measurement capabilities. Data acquired by GRaND will be made available to the public through the Planetary Data System’s Small Bodies Node. The paper will be a valuable resource for scientists who want to study the chemical makeup of Vesta.
PSI’s William Feldman, Jeffrey Morgenthaler, Karly Pitman and Robert Reedy are among the paper’s co-authors. PSI’s Naoyuki Yamashita, a veteran of the Japanese mission Kaguya, recently joined the GRaND team and is helping to analyze the data acquired at Vesta.
GRaND is operated by the Planetary Science institute under the leadership of Senior Scientist Tom Prettyman, who is also the lead for Geochemistry on Dawn. This work is supported by NASA under a subcontract from the Jet Propulsion Laboratory to the Planetary Science Institute. GRaND was built by Los Alamos National Laboratory under Prettyman’s direction and supervision.
The Dawn mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory for NASA’s Science Mission Directorate, Washington, D.C. It is a project of the Discovery Program managed by NASA’s Marshall Space Flight Center, Huntsville, Ala. UCLA is responsible for overall Dawn Mission science. Orbital Sciences Corporation in Dulles, Va. designed and built the Dawn spacecraft.
Information about Dawn is available at: http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov.
CONTACT:
Tom Prettyman
Senior Scientist
505-690-5128
Solstice Event Saturday Begins Educational Collaboration Between Planetary Science Institute and Children’s Museum Tucson
Dec. 12, 2011 Tucson, Ariz. -- The Planetary Science Institute and Children’s Museum Tucson are partnering to offer local youngsters a fun and educational look at our solar system – and beyond.
A Winter Solstice event from 1-4 p.m. Dec. 17 will offer lots of hands-on activities for kids age 2 to 10, said Coppelia Tarantal, the museum’s early childhood education specialist.
The museum is located at 200 S. Sixth Ave. Admission is $2 for children and adults, she said.
PSI’s Education Specialist Sanlyn Buxner and Senior Scientist Steve Kortenkamp will be on hand to help youngsters explore the Sun-Earth system. They will be facilitating art and science activities related to the sun and Earth in celebration of the solstice.
In addition to PSI, participating organizations include Puppets Amongus, Planet Djembe and Cub Club Samba, said Tarantal, also known as Miss CoCo at the museum.
PSI’s participation in the event – the first of many planned where the Institute will partner with Children’s Museum Tucson – is funded by a three-year, $150,000 grant from NASA’s Space Science Directorate Supplemental Education Awards for ROSES Investigators.
The “Out of this world: bringing space rocks that hit the Earth to children and families” program will see PSI create meteorite kits for the museum and developing and implementing museum interpretative programming and classroom outreach.
PSI will also participate in and support family learning events at the museum. PSI and the museum are co-developing a new Out of This World summer camp that will be offered in the summer of 2012. Scholarships will be provided for campers provided by the grant.
“We are thrilled to be working with Children’s Museum Tucson on this new project,” said Buxner. “This will be the first of many exciting events to bring space science to children of all ages in the Tucson community.”
CONTACTS
Sanlyn Buxner
Education Specialist
520-202-5833
buxner@psi.edu
Steve Kortenkamp
Senior Scientist
520-245-8197
kortenka@psi.edu
Mars Science Laboratory to Offer New Scientific Insights
During its planned lengthy surface mission, the Mars Science Laboratory rover Curiosity will assess whether Mars ever was, or is still today, a habitable environment able to support microbial life.
Yingst, a Senior Scientist at PSI, is Deputy Principal Investigator on MAHLI (Mars Hand Lens Imager) and a Co-Investigator on MARDI (Mars Descent Imager) and MastCam (Mast Camera).
“Curiosity is the first rover designed to be both field geologist and portable laboratory,” Yingst said. “It has many of the characteristics of other rovers, but it also has instruments that will allow it to look for evidence of carbon compounds in samples. This is something that your typical field geologist could only do in the lab.”
The MastCam will take color images and color video footage of the Martian terrain.
“CheMin uses X-ray diffraction to determine the mineralogy of the sample,” Vaniman said. “This is the first time that this powerful standard laboratory method of determining mineralogy will be used on another planet. Ability to measure fluoresced as well as diffracted X-rays makes CheMin especially versatile because it will determine both crystal structure and chemical composition.”
Curiosity’s ability to study its environment from the scale of kilometers to atoms makes it an extraordinarily capable system that will revolutionize our understanding of Mars.
CONTACTS:
R. Aileen Yingst
Senior Scientist
920-360-3627
David Vaniman
Senior Scientist
520-667-1863
PSI researcher’s 20th Children’s Science Book is Published
Oct. 18, 2011 -- Tucson, Ariz. -- Planetary Science Institute Senior Scientist Steve Kortenkamp reached a literary milestone when his 20th children’s book on science – “Asteroids, Comets, and Meteoroids” – was published.
Beginning in 2007 with his first book – the controversial and critically acclaimed “Why Isn’t Pluto a Planet?” – Kortenkamp has written books covering an array of space science topics including “The Milky Way,” “Space Robots,” “Dwarf Planets,” “NASA,” “Space Junk” and “Planets of Our Solar System.”
The peer-reviewed books are published by Capstone Press for younger readers ranging from grade K-5. “Kids like topics like space, and these books get them reading,” Kortenkamp said. “If you give them interesting books about space, reading can be exciting for them.”
Kortenkamp started out as a book consultant for Capstone Press in 2004 and worked on more than a dozen titles. Impressed with his comments and suggestions, the editors at Capstone eventually asked Kortenkamp to begin writing the books himself.
Kortenkamp hopes to continue his prolific literary output. “I’m trying to interest Capstone in books about rings, satellites and space dust,” he said.
It takes him about two weeks of very intense effort to develop a book outline and write the first draft. Following that, each book goes through a peer-review process. “The fact that these books are reviewed by other scientists and educators puts them at a different level,” Kortenkamp said.
His favorite title is his first: “Why Isn’t Pluto a Planet?” “This is a controversial topic with older generations,” he said. “But kids in school nowadays are learning from the Pluto controversy that science is about discovering new things and that it is okay to change your mind when you learn something new.”
The books are available at Amazon.com.
A photo of Kortenkamp is available at http://www.psi.edu/webfm_send/263
CONTACT:
Steve Kortenkamp
Senior Scientist
520 245 8197
kortenka@psi.edu
Young Clays on Mars Could Have Been Habitable Regions for Life
Sept. 19, 2011, Tucson, Ariz. -- Two small depressions on Mars found to be rich in minerals that formed by water could have been places for life relatively recently in the planet’s history, according to a new paper in the journal Geology.
Smectites are a specific type of clay mineral that readily expands and contracts with adsorbed water. They contain Silica, plus Aluminum, Iron or Magnesium in their structures. They form by the alteration of other silicate minerals in the presence of non-acidic water.
Weitz and her co-authors studied approximately 300 meters of vertically exposed layered rocks within two 30 to 40 kilometer depressions, called troughs, near the western end of the Valles Marineris canyon system. 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, said Weitz, a HiRISE team member.
Each trough probably experienced multiple episodes where water partially filled in low-lying regions and deposited 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.
“These clays formed from persistent water in neutral to basic conditions around 2 to 3 billion years ago, indicating these two troughs are unique and could have been a more habitable region on Mars at a time when drier conditions dominated the surface,” said co-author and CRISM team member Janice Bishop from the SETI Institute and NASA AMES Research Center.
CONTACT:
Catherine M. Weitz
Senior Scientist
520-622-6300, x310
NASA Grant Funds Research on Jupiter Plasma Ring “Energy Crisis”
One of the long-term puzzles of the Io Plasma Torus concerns the observed imbalance between the well-known sources of energy input and output from the Io Plasma Torus. It is possible to calculate how much energy the torus receives when newly formed ions join the torus. It is also possible to observe how much energy leaves the torus by looking at the total energy of all of the photons it emits. The "energy crisis" is that about twice as much energy leaves the torus than is currently known to be added to it.
Morgenthaler has been part of a team of researchers, originally from the University of Wisconsin, which has been collecting observations of Io and the plasma torus for more than two decades. These observations include spectra and images of the plasma torus and spectra of Io. The observations have been recorded at the McMath-Pierce Solar Telescope on Kitt Peak, Arizona.
Using a solar telescope – chosen because there is not a high demand for a solar telescope at night – has allowed continuous multi-week studies of the Io Plasma Torus to be conducted in many of the past 20 years. This time coverage is essential for sorting out the variations in the magnetic field configuration that might lead to a solution to the "missing energy" problem.
Spacecraft visits to Jupiter, like the upcoming Juno mission, provide invaluable information that is not available from the ground. Interestingly, the spectroscopic observations of Io that Morgenthaler is working with essentially turn this moon into a spacecraft with a plasma sensor. Using these spectra, Morgenthaler and collaborator Ronald Oliversen of NASA Goddard Space Flight Center have been able to detect an emission line of oxygen in Io's atmosphere, which changes brightness as Io moves in and out of the denser regions of the torus. The brightness changes are mostly well understood, however, occasionally there is a period of an hour or so where the oxygen emission from Io is unusually bright. Morgenthaler and his colleagues suspect that these "departure events" are triggered by flux tube interchange events and therefore may help solve the missing energy problem.
CONTACT:
Jeff Morgenthaler, Ph.D.
Senior Scientist
207-231-4036
Juno Mission Will Open Jupiter up to the Public
Aug. 9, 2011 -- NASA’s Juno spacecraft, which left Earth Aug. 5 to began its five-year, 1.7 billion-mile journey to Jupiter, will offer the public the opportunity to participate in the mission’s science endeavors, said a researcher from the Planetary Science Institute.
The mission will also provide researchers with spectacular close-up color images of Jupiter, including the first detailed glimpses of the planet’s poles, said Candice Hansen-Koharcheck, a senior research scientist at the Planetary Science Institute and co-investigator on the Juno mission. She is also science lead for the spacecraft’s camera, called the JunoCam.
“In addition to returning images of the poles of Jupiter from Juno’s unprecedented perspective in its polar orbit, the camera will provide an opportunity for the public to be directly involved in a space mission,” Hansen-Koharcheck said. “We are going to have the public help us decide which images we take, and when they will be taken.”
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.
“The first step is to engage the amateur astronomy community to supply us with their data and send us their pictures,” she said. “We will need to see what Jupiter is doing in 2016.”
The public will be invited to weigh-in on which pictures should be taken. The images will be released to the public. “We will put our raw images out and ask them to process that data,” she said.
The JunoCam camera, built by Malin Space Science Systems in San Diego, is a push-frame imager designed to acquire images while the spacecraft is rotating. Its 58-degree field of view is optimized for the view of the poles of Jupiter. Images will exceed Cassini resolution at about an hour from closest approach. At the spacecraft’s closest approach to Jupiter the image resolution will be better than 5 kilometers.
“JunoCam is dedicated to public outreach and education,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio, Texas. “We’re excited to get the first pictures of Jupiter’s poles.”
Hansen also co-leads the Juno Science Planning Working Group, charged with allocating scarce spacecraft resources such as data volume and energy, among all the instruments on the payload. The Science Planning Working Group creates timelines of instrument activities, and organizes observing campaigns.
The spacecraft is expected to arrive at Jupiter in July 2016. The Juno spacecraft – the first to operate around an outer planet using solar power – will orbit Jupiter's poles 33 times, investigating the gas giant's origins, structure, atmosphere and magnetosphere.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.
CONTACT:
Candice Hansen-Koharcheck
Senior Scientist
626-483-5640
cjhansen@psi.edu
Atsa Subortibal Observatory Team Completes First Training
Members of the Planetary Science Institute’s Atsa Suborbital Observatory project participated in a suborbital scientist training course at the NASTAR Center in Southampton, Penn.
Pictured here, left to right, are Gregory Kennedy (NASTAR), Andrew Strasburger (Wofford College), Daniel Pittman (The Citadel), Ryan Boodee (The Citadel), Daniel Showers (Clemson University), Luke Sollitt (The Citadel), Brent Garry (PSI), Mark Sykes (PSI), Melissa Lane (PSI) and Brienna Henwood (NASTAR).
Photo credit: Brad Waugh, NASTAR Center
July 21, 2011 -- PSI scientists and undergraduate students from The Citadel and other South Carolina colleges received training in support of PSI's human-tended Atsa Suborbital Observatory at the National AeroSpace Training and Research (NASTAR) Center in Southampton, Penn.
The Atsa project will use a reusable suborbital spacecraft equipped with a specially designed telescope to provide low-cost space-based observations above the contaminating atmosphere of Earth, while avoiding some operational constraints of satellite telescope systems.
The three-day NASTAR Suborbital Scientist course equips individuals with hands-on knowledge and skills to safely cope with the rigors of suborbital spaceflight and gives an understanding of the challenges involved with conducting experiments in space. The course includes four core elements: Altitude Physiology, G-Tolerance, Space Launch and Reentry Training, and Distraction Management.
High-altitude physiology training enables trainees to experience the effects of hypoxia or oxygen-deprivation firsthand with an altitude chamber flight to 25,000 feet. Trainees also learn safety protocols and considerations in a loss of cabin pressure event.
G-tolerance flights introduce trainees to the physiological and physiological acceleration effects of spaceflight and teach ways to mitigate the symptoms of gravity-induced loss of consciousness (G-LOC). Simulated space flights are conducted on the NASTAR Phoenix STS-400 centrifuge where trainees learn to handle the maximum acceleration G loads encountered during launch and reentry up to three and one half times Earth’s gravity oriented up-and-down (eyeballs-down) and six times Earth’s gravity oriented front-to-back (eyeballs-in).
This is the first NASTAR suborbital science class dedicated to a single project or program. The NASTAR training included simulated spaceflights in a centrifuge. Team members flew profiles for Virgin Galactic's SpaceShip2 and a vehicle approximating XCOR's Lynx. PSI and XCOR Aerospace recently signed a Memorandum of Understanding laying the groundwork for flying Atsa on their Lynx spacecraft.
PSI Senior Scientist Faith Vilas and PSI Affiliate Scientist Luke Sollitt, who is an Assistant Professor at The Citadel, are the inventors of Atsa and were present, overseeing the training and collecting information to be used in designing training activities for Atsa operators.
“NASTAR is providing essential input for designing the training regimen we will require for Atsa operators,” said Vilas.
“Because this is a human-tended observatory, we need to understand in more than a theoretical way how the operator will be affected by the launch environment,” said Sollitt. “This will also impact the design of the interfaces and the instrument itself.”
Atsa telescope operations will commence immediately after the spacecraft’s main engine cutoff. Those participating in the flight simulations conducted a number of exercises to understand how performance would be affected by recently experienced G-forces.
Also participating from PSI were Research Scientist Brent Garry, CEO and Director Mark Sykes, and Senior Scientist Melissa Lane. The undergraduate students are participating in the South Carolina Space Grant consortium’s Palmetto Academy program under the supervision of Professor Sollitt and are involved in the design and construction of the Atsa Mark 1. These students included Andrew Strasburger from Wofford College, Daniel Showers from Clemson University, and Ryan Boodee and Daniel Pittman from The Citadel.
“The Atsa team are driven to establish the first human-tended observatory in space using suborbital vehicles,” said Brienna Henwood, Director of Space Training and Research Programs at the NASTAR Center. “It was a pleasure to work with the Atsa team in designing tangible research activities and simulated spaceflight missions that will enable them know what to expect in flight and plan their space mission accordingly. NASTAR Center looks forward to a long-term relationship with PSI and the Atsa team as their project develops further. “
CONTACT:
Faith Vilas
Atsa Project Scientist, PSI Senior Scientist
281-851-8947
fvilas@psi.edu
Planetary Science Institute Selects XCOR to Fly Atsa Suborbital Observatory
July 11, 2011 -- The Planetary Science Institute (PSI) and XCOR Aerospace have signed a Memorandum of Understanding that lays the groundwork for flying the human-operated Atsa Suborbital Observatory aboard XCOR’s Lynx spacecraft.
The Atsa project will use crewed reusable suborbital spacecraft equipped with a specially designed telescope to provide low-cost space-based observations above the contaminating atmosphere of Earth, while avoiding some operational constraints of satellite telescope systems.
"The XCOR vehicle design and capabilities work well for hosting the kind of observing facility we are developing," said PSI Senior Scientist Faith Vilas, the Atsa Project Scientist.
The Atsa Suborbital Observatory was invented by Vilas and Luke Sollitt, a PSI affiliate scientist who is a professor at The Citadel, The Military College of South Carolina. Vilas, who leads the Atsa project, is a long-time planetary astronomer who recently retired as director of the MMT Observatory (a joint facility of the Smithsonian Institution and the University of Arizona) before joining PSI. Sollitt, the Atsa Deputy Project Scientist, was formerly staff scientist at Northrop Grumman Corp.
“NASA has been flying suborbital observatories for decades, on unmanned, disposable rockets. The new manned, reusable commercial platforms will allow us to make repeated observations with a single instrument, but without the need to refurbish it between flights,” Sollitt said. “In addition, the short turn-around means we can do many observations or targets.”
Atsa means "eagle" in the Navajo language. The facility is optimized for observing solar system objects near the sun that are difficult to study from orbital observatories such as Hubble and ground-based telescopes.
"These are natural targets for instruments on suborbital rockets to observe, but a human-tended facility using the kind of reusable launch vehicle offered by XCOR offers significant cost savings," said Mark Sykes, CEO and Director of PSI, who is also a long-time planetary astronomer and is training to be an Atsa operator.
The Lynx spacecraft will fly to space on a customized flight trajectory and will be capable of precision pointing, allowing the Atsa system with its operator to acquire the desired target and make the planned observations. "We are being approached by many potential customers who are interested in supporting observations of the inner solar system," Vilas said. "We will also be able to support target of opportunity observations for newly discovered objects and other phenomena."
“We’re looking forward to flying PSI’s Atsa system on Lynx, it will be a groundbreaking experience. The rapid and flexible operations of the Lynx will enable scientists to pick specific targets of interest and the same day fly multiple tailor made observation missions quickly and inexpensively when they want them to be flown,” said Khaki Rodway McKee, XCOR’s Program Manager.
"We are entering into a new era in the human exploration of space, where private companies like XCOR and PSI will begin to play leading roles in certain areas, beginning with suborbital flight – harkening back to the days of NASA's Mercury program," Sykes said.
Andrew Nelson, XCOR’s Chief Operating Officer, said, “Much like the early days of the Internet, mobile communications and social networking revolutions saw new and innovative applications drive commercial multi-billion dollar marketplaces, so we are seeing privately funded efforts like PSI’s Atsa as a key early adopter signaling a robust future for suborbital reusable launch vehicles.”
Public investment still plays a critical role in shaping the future of humans beyond Earth. "NASA is still the tip of the spear," Sykes said. "There are basic questions regarding expanding Earth life to different gravities and the availability and usability of space resources that require NASA to answer. Together, private enterprise and the public sector can realize our dreams of a future in space."
The Planetary Science Institute is a private, nonprofit 501(c)(3) corporation dedicated to solar system exploration. It is headquartered in Tucson, Ariz. where it was founded in 1972. PSI scientists are involved in numerous NASA and international missions, the study of Mars and other planets, the Moon, asteroids, comets, interplanetary dust, impact physics, the origin of the solar system, extra-solar planet formation, dynamics, the rise of life, and other areas of research. They conduct fieldwork in North America, Australia and Africa. They also are actively involved in science education and public outreach through school programs, children’s books, popular science books and art. PSI scientists are based in 15 states, the United Kingdom, Switzerland, Russia, Australia and Canada. (www.psi.edu).
XCOR Aerospace is a California corporation located in Mojave, Calif. The company is in the business of developing and producing safe, reliable and reusable rocket powered vehicles, propulsion systems, advanced non-flammable composites and other enabling technologies. XCOR is working with aerospace prime contractors and government customers on major propulsion systems, and concurrently building the Lynx, a piloted, two-seat, fully reusable, liquid rocket powered vehicle that takes off and lands horizontally, and serves three primary missions: nano-satellite launch, research & scientific missions, and private spaceflight. The Lynx production models (designated Lynx Mark II) are designed to be robust, multi-mission commercial vehicles capable of flying to 100+ km in altitude up to four times per day and are being offered on a wet lease basis. (www.xcor.com).
CONTACT:
Faith Vilas
Atsa Project Scientist, PSI Senior Scientist
281-851-8947
MESSENGER’s Data Offers Insights on Inner Planet
June 16, 2011 -- The Mercury MESSENGER spacecraft has discovered a wealth of new information, including a few scientific surprises, after orbiting the planet closest to the sun for almost three months.
After MESSENGER’s historic entry into orbit around Mercury on March 18, instruments aboard the spacecraft have provided researchers with new data on the planet’s geochemistry, geophysics, geologic history, atmosphere, magnetosphere, and plasma environment.
The Magnetometer instrument on the spacecraft has shown that the magnetic field of Mercury is much like that of the Earth in that it has a north pole and south pole, each approximately aligned with the opposite geographic pole. However, unlike on Earth, the magnetic equator on Mercury is systematically offset about 480 kilometers northward of Mercury’s geographic equator.
“This is an exciting result that suggests something fundamentally different about what processes play a key role in the generation of Mercury’s magnetic field compared with those important to Earth’s magnetic field,” said Catherine Johnson, Planetary Science Institute senior scientist, University of British Columbia professor of geophysics and MESSENGER mission participating scientist. “The result may have important implications for the internal dynamics of the planet and how the planet cools today.”
Other PSI researchers working on the MESSENGER mission include Deborah Domingue Lorin, William Feldman, Robert Gaskell, Faith Vilas and Elizabeth Jensen.
With MESSENGER’S instruments performing the first complete reconnaissance of Mercury, major features on the planet – previously seen only at comparatively low resolution – are now in sharp focus. Measurements of the chemical composition of Mercury’s surface are providing important clues to the origin of the planet and its geological history. Maps of the planet’s topography and magnetic field are revealing new clues to Mercury’s interior dynamical processes. And scientists now know that bursts of energetic particles in Mercury’s magnetosphere are a continuing product of the interaction of Mercury’s magnetic field with the solar wind.
“MESSENGER has passed a number of milestones just this week,” said MESSENGER principal investigator Sean Solomon of the Carnegie Institution of Washington. “We completed our first perihelion passage from orbit on Sunday, our first Mercury year in orbit on Monday, our first superior solar conjunction from orbit on Tuesday, and our first orbit-correction maneuver on Wednesday. Those milestones provide important context to the continuing feast of new observations that MESSENGER has been sending home on nearly a daily basis.”
As part of MESSENGER’s global imaging campaign, the Mercury Dual Imaging System (MDIS) is acquiring global monochrome and stereo base maps with an average resolution of 250 meters per pixel and a global color base map at an average of 1.2 kilometer per pixel. These base maps are providing the first global look at the planet under optimal viewing conditions.
The broad expanses of plains near Mercury’s north pole seen in orbital imaging confirm that volcanism shaped much of Mercury’s crust and continued through much of Mercury’s history. MESSENGER’s new orbital images show that the plains are likely among the largest expanses of volcanic deposits on Mercury, with thicknesses of up to several kilometers
The X-Ray Spectrometer (XRS) — one of two instruments on MESSENGER designed to measure the abundances of many key elements on Mercury — has made several important discoveries since the orbital mission began. The magnesium/silicon, aluminum/silicon, and calcium/silicon ratios averaged over large areas of the planet’s surface show that, unlike the surface of the moon, Mercury’s surface is not dominated by feldspar-rich rocks.
XRS observations have also revealed substantial amounts of sulfur at Mercury’s surface, lending support to prior suggestions from ground-based telescopic spectral observations that sulfide minerals are present. This discovery suggests that the original building blocks from which Mercury was assembled may have been less oxidized than those that formed the other terrestrial planets, and it has potentially important implications for understanding the nature of volcanism on Mercury.
MESSENGER’s Gamma-Ray and Neutron Spectrometer has detected the decay of radioactive isotopes of potassium and thorium and has allowed a determination of the bulk abundances of these elements.
MESSENGER’s Mercury Laser Altimeter has been systematically mapping the topography of Mercury’snorthern hemisphere. After more than 2 million laser-ranging observations, the planet’s large-scale shape and profiles of geological features are both being revealed in high detail. The northpolar region of Mercury, for instance, is a broad area of low elevations. The overall range in topographic heights seen to date exceeds 9 kilometers.
Two decades ago, Earth-based radar images showed that near both Mercury’s north and south polesare deposits characterized by high radar backscatter. These polar deposits are thought to consist of water ice and perhaps other ices preserved on the cold, permanently shadowed floors of high-latitude impact craters. MESSENGER’s altimeter is testing this idea by measuring the floor depths of craters near Mercury’s north pole. To date, the depths of craters hosting polar deposits are consistent with the idea that those deposits occupy areas in permanent shadow.
One of the major discoveries made by Mariner 10 during the first of its three flybys of Mercury in 1974 were bursts of energetic particles in Mercury’s Earth-like magnetosphere. Four bursts of particles were observed on that flyby, so it was puzzling that no such strong events were detected by MESSENGER during any of its three flybys of the planet in 2008 and 2009. With MESSENGER now in near-polar orbit about Mercury, energetic events are being seen almost like clockwork.
With Mercury’s smaller magnetosphere and with the lack of a substantial atmosphere, both the generation of these energetic electrons and their distribution are different than at Earth. One candidate mechanism for the generation of these energetic electrons is the formation of a “double layer,” a plasma structure with large electric fields along the local magnetic field. Another is induction brought about by rapid changes in the magnetic field, a process that follows the principle used in generators on Earth to produce electric power. Which of these mechanisms, if either, predominates in their acceleration will be the subject of study over the coming months.
“We are assembling a global overview of the nature and workings of Mercury for the first time and many of our earlier ideas are being cast aside as new observations lead to new insights,” Solomon said. “Our primary mission has another three Mercury years to run, and we can expect more surprises as our solar system’s innermost planet reveals its long-held secrets.”
CONTACT:
Catherine Johnson
Senior Scientist
619-846-3957
Small Mass of Mars Could be Due to Planetary Orbital Migration
June 5, 2011 -- A long-ago inward migration by Jupiter during the formation of our Solar System could explain why Mars is small in relation to Earth and Venus, according to a paper published in Nature.
Researchers have long sought to explain the small mass of Mars, which has remained an outstanding problem in terrestrial planet formation, said David P. O’Brien, a Research Scientist at the Planetary Science Institute and co-author of A low mass for Mars from Jupiter’s early gas-driven migration that appears in Nature.
“This work not only solves a difficult problem in Solar System formation,” O’Brien said, “it shows that the solution lies in the giant planets of our Solar System undergoing significant early migration, which was generally thought to only have occurred in extrasolar planetary systems.”
Simulations of the formation process of the four inner planets in the Solar System – Mercury, Venus, Earth and Mars – generally produced a version of Mars far more massive than the real planet.
“We tried a large variety of simulation parameters to solve this problem, but nothing seemed to work,” O’Brien said.
A 2009 paper by Brad Hansen from UCLA offered a new clue: Hansen showed that if the initial distribution of solid material in the solar system was assumed to have an outer boundary at 1 Astronomical Unit (1 AU being the current distance from the sun to Earth), a smaller Mars could form.
The presence of a sharp outer boundary at 1 AU required in Hansen's work was hard to explain, given the existence of the asteroid belt between 2 and 4 AU, the giant planets between 5 and 30 AU and the Kuiper Belt beyond that.
However, it has been shown in numerical simulations over the past decade that Jupiter and Saturn could migrate in the early Solar System when gas was still present, and in some cases could move inwards and then back outwards to roughly their current locations.
“Rapidly the pieces of the story came together,” said Kevin J. Walsh, lead author of the paper who began work on the project at the Observatoire de la Cote d'Azur in Nice, France and is now at the Southwest Research Institute in Bounder, CO. “If Jupiter had moved inwards from its birth place down to 1.5 AU from the sun and then had turned around because of the formation of Saturn, eventually migrating outwards towards its current location, it would have truncated the distribution of solids in the inner Solar System at about 1 AU, as required to explain the small mass of Mars.”
Jupiter now orbits the sun at 5.2 AU.
“The problem was to understand whether the inward and outward migration of Jupiter through the 2-4 AU region could be compatible with the existence of the asteroid belt today,” Walsh said. “So we started to do a huge number of simulations.”
“The asteroid belt, which was a priori our main problem, turned out to be the main strength of our model,” said O’Brien.
“The result was fantastic,” Walsh said. “The simulations showed that the migration of Jupiter was consistent with the existence of the asteroid belt, but it also explained properties of the belt never understood before.”
The passage of Jupiter depleted then re-populated the asteroid belt region, with inner-belt bodies originating between 1 and 3 AU and outer belt bodies originating in a very distinct region between and beyond the giant planets, naturally producing the significant compositional differences existing today across the belt.
The model was called the “Grand Tack Scenario” with Jupiter’s motion similar to a sailboat tacking around a buoy.
Other authors are Alessandro Morbidelli (Observatoire de la Cote d'Azur, France), Sean N. Raymond (Observatoire de Bordeaux, France) and Avi M. Mandell (NASA Goddard).
O’Brien’s work was funded by a grant to PSI from NASA’s Planetary Geology and Geophysics research program.
CONTACT:
David P. O’Brien
Research Scientist
520-547-3977
Researchers gain new insights into Comet Hartley 2
An image of comet Hartley 2 taken on Sept. 3, 2010 at the 2.1 meter telescope
at the Kitt Peak National Observatory near Tucson, Ariz. In this image, red denotes
regions where CN gas is more abundant. The image is enhanced by removing the
underlying background in order to highlight the jet feature present. North is up
and east is to the left. The image is nearly 50,000 miles across and the comet nucleus
which is not resolved is at the center. The red streaks are star trails.
May 16, 2011-- A tumbling comet nucleus with a changing rotational rate has been observed for the first time, according to a new paper by a Planetary Science Institute researcher.
These findings, as well as information gleaned from a recent NASA EPOXI spacecraft flyby of Comet 103P/Hartley 2, are expected to offer new insights as researchers strive to better understand comets and the role they could possibly play in aiding human solar system exploration, said Nalin H. Samarasinha, senior scientist at PSI and lead author of a paper titled Rotation of Comet 103P/Hartley 2 from Structures in the Coma that appears in Astrophysical Journal Letters.
“Understanding the makeup of comets has immediate relevance to planetary explorations efforts. Small bodies of the solar system such as asteroids and comets could potentially act as way stations, as well as to supply needed resources, for the human exploration of the solar system,” Samarasinha said. “For this purpose, it is necessary to know the properties and the character of these objects to maximize our investment. ”
The research team analyzed images of the rotationally excited, or tumbling, Hartley 2 comet taken during 20 nights between Sept. 1 and Dec. 15, 2010 using the 2.1-meter telescope at Kitt Peak National Observatory near Tucson, Ariz.
A blue filter that isolates the light emitted by cyanogen (CN) molecules was used to observe CN features in the coma of the comet, Samarasinha said. This showed clear variations over time scales ranging from a few hours to over several days. The coma is the extended “atmosphere” of the comet that surrounds the solid nucleus that consists of ice and dirt.
“The rotational state of a comet’s nucleus is a basic physical parameter needed to accurately interpret other observations of the nucleus and coma. Analysis of these cyanogen features indicates that the nucleus is spinning down and suggests that it is in a state of a dynamically excited rotation,” he said. “Our observations have clearly shown that the effective rotation period has increased during the observation window.”
The team is the first group to point this out based on their observations from early September and early October.
Hartley 2, a relatively small comet with a 2-kilometer long nucleus, is highly active for its size, he said. It is experiencing rotational changes due to torque caused by jets of gases emitting from the icy body.
Information on the makeup of Hartley 2 gleaned from this research and the EPOXI flyby, and similar research on additional comets, could offer the early tools researchers need to determine the best way to deal with a comet on a collision course with Earth.
“Although extremely rare, comets can collide with Earth. This could cause regional or global damage to the environment and to life on Earth. However, fortunately for the first time, we are on the threshold of our technical knowhow to mitigate such a hazardous impact,” Samarasinha said. “In order to do that we need to know the material properties of comets. The most appropriate mitigation strategy for a strong rigid body is different from that for a weakly bound agglomerate.”
Hartley 2 offered a significant opportunity for research, said co-author Beatrice E.A. Mueller.
“This comet had such a great apparition – it came close to Earth and was observable from the ground over months with great resolution, and was encountered by the EPOXI spacecraft,” said Mueller, PSI Senior Scientist and Principal Investigator of the NASA Planetary Astronomy Grant to PSI that funded the study. “Ultimately, one wants to deduce the physical parameters of the nucleus as well as its structure. This will give insights into the conditions during the formation of the solar system.”
Other authors of the paper are Michael F. A’Hearn, Tony L. Farnham and Alan Gersch, all of the University of Maryland Department of Astronomy.
CONTACT:
Nalin Samarasinha
Senior Scientist
520 547 3952
Northern Mars Landscape Actively Changing
Feb. 3, 2011 -- The avalanche faces of huge Martian sand dunes, long thought to be frozen in time on the distant planet, are being re-sculpted on a seasonal basis, according to results of an investigation led by a Planetary Science Institute researcher.
The vast northern dunes on Mars – covering an area larger than Texas at 845,000 square kilometers – were believed by planetary scientists to be fairly static, shaped long ago when winds on the planet’s surface were much stronger than seen today, said Candice Hansen, a senior scientist at PSI and lead author of a paper titled “Seasonal Erosion and Restoration of Mars’ Northern Polar Dunes” that appears in the journal Science this week.
New images from the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter tell a different story.
“Many dunes in the northern polar region of Mars have shown substantial changes in morphology within just one Martian year,” said Hansen, who also serves as deputy principal investigator on the HiRISE team.
A seasonal layer of frozen carbon dioxide, or dry ice, that blankets the region in winter and sublimates, or changes from solid to gas state, in the spring is responsible for the annual erosion of the polar Martian dunes, Hansen said.
“This gas flow destabilizes the sand, causing avalanches and creating new alcoves, gullies and sand aprons on Martian dunes,” she said.
Comparing images from the HiRISE camera taken over two Mars years – about four Earth years – the team led by Hansen discovered that the dunes they studied at high latitudes showed changes indicating that they are not strongly crusted or ice cemented, as previously assumed by Mars scientists.
“The level of erosion in just one Mars year was really astonishing,” Hansen said. “In some places hundreds of cubic yards of sand have avalanched down the face of the dunes.”
The orbiting HiRISE camera obtained a series of images in several northern polar locations so the team could study the seasonal process of ice sublimation. Before and after images were compared in the hopes of detecting subtle changes. Visit http://www.psi.edu/news/press-releases/hansen.html to see HiRISE images used in the research project.
To their surprise the team found new deep alcoves scarring the brinks of dunes. Sand avalanching from the top of the dune spread out in aprons extending over the ground beneath the dunes, changing dune boundaries. The changes in dune morphology are correlated with locations of enhanced seasonal activity (as shown in the HiRISE images). Seasonal activity shows up as dark particles ejected out from under the seasonal ice layer, which then settle out on top of the bright ice.
"Melting H2O snow and ice are known to cause sand avalanches and flows on Earth’s Antarctic dunes, but it would seem that the erosive action of carbon dioxide ice sublimation is unique to sand dunes on Mars," said Mary Bourke, PSI senior scientist and co-author.
Especially surprising was the discovery that scars of past sand avalanches could be partially erased in just one Mars year by the movement of small ripples. Models of Mars’ atmosphere do not predict wind speeds adequate to lift sand grains, and data from Mars landers at lower latitudes show high winds are a rare occurrence.
“Perhaps polar weather is more conducive to high wind speeds,” Hansen said.
HiRISE has an ongoing campaign to re-image dunes at all latitudes to understand winds in the current climate on Mars, Hansen said. The research was funded by a Mars Reconnaissance Orbiter program grant from NASA.
“Understanding how Mars is changing today is a key first step to understanding basic planetary processes and how Mars’ climate changes over time,” said Alfred McEwen, HiRISE principal investigator and paper co-author.
CONTACT:
Candice Hansen
Senior Scientist
626-483-5640
