European Association for Astronomy Education

Source: MESSENGER Mission Highlights

MLA coverage (left) of Mercury as May 21, 2011.
Image credit: NASA/Messenger Mission.

MESSENGER's Mercury Laser Altimeter (MLA) in its first two months of operation has already built up a grid of ground tracks that span most of Mercury’s surface north of the equator. (read more)

Source: NASA News

False-color infrared image, obtained by Cassini spacecraft,
shows a powerful storm in Saturn's northern hemisphere.
Image credit: NASA/JPL/Univ. of Arizona.

NASA's Cassini spacecraft and a European Southern Observatory Very Large Telescope (VLT) tracked the growth of a giant early-spring storm in Saturn's northern hemisphere so powerful it stretches around the entire planet. The rare storm has been wreaking havoc for months and shot plumes of gas high into the planet's atmosphere.

Cassini's radio and plasma wave science instrument first detected the large disturbance, and amateur astronomers tracked its emergence in December 2010. As it rapidly expanded, its core developed into a giant, powerful thunderstorm. The storm produced a 3,000-mile-wide (5,000-kilometer-wide) dark vortex, possibly similar to Jupiter's Great Red Spot, within the turbulent atmosphere.

The dramatic effects of the deep plumes disturbed areas high up in Saturn's usually stable stratosphere, generating regions of warm air that shone like bright "beacons" in the infrared. Details are published in this week's edition of Science Magazine. (read more)

Links:

NASA Cassini Mission
ESO Science Release eso1116
NASA Science News

Source: NASA-Solar System Exploration

New data analysis from NASA's Galileo spacecraft reveals a subsurface ocean of molten or partially molten magma beneath the surface of Jupiter's volcanic moon Io.

The finding heralds the first direct confirmation of this kind of magma layer at Io and explains why the moon is the most volcanic object known in the solar system. The research was conducted by scientists at the University of California, Los Angeles, the University of California, Santa Cruz, and the University of Michigan.

The study is published this week in the journal Science. (read more)

Source: MESSENGER Mission

On May 6^th MESSENGER completed its 100^th orbit around Mercury. Since its insertion into orbit about the innermost planet on March 17, the spacecraft has executed nearly 2 million commands.

The data gathered so far include more than 70 million magnetic field measurements, 300,000 visible and infrared spectra of the surface, 16,000 images, and 12,000 X-ray and 9,000 gamma-ray spectra probing the elemental composition of Mercury’s uppermost crust. (read more)

Source: NASA Discovery Program

NASA has selected three science investigations from which it will pick one potential 2016 mission to look at Mars' interior for the first time; study an extraterrestrial sea on one of Saturn's moons; or study in unprecedented detail the surface of a comet's nucleus.

Each investigation team will receive $3 million to conduct its mission's concept phase or preliminary design studies and analyses. After another detailed review in 2012 of the concept studies, NASA will select one to continue development efforts leading up to launch. The selected mission will be cost-capped at $425 million, not including launch vehicle funding.

NASA's Discovery Program requested proposals for spaceflight investigations in June 2010. A panel of NASA and other scientists and engineers reviewed 28 submissions. The selected investigations could reveal much about the formation of our solar system and its dynamic processes. Three technology developments for possible future planetary missions also were selected. (learn more)

Source: MESSENGER Mission

MESSENGER carries a Gamma-Ray Spectrometer (GRS) capable of measuring and characterizing gamma-ray emissions from the surface of Mercury. Gamma rays coming from Mercury carry information about the concentrations of elements present on its surface, and observations from the GRS are being used to determine the surface composition of the planet. (read more)

Source: Chandra Blog

Chandra team has announced the launch of a new – and yet somewhat familiar -- project. “From Earth to the Solar System” has officially opened on April 25th. The team has put together a new collection of images from the Solar System.

Source: MESSENGER Mission

.MLA’s first measurements from Mercury orbit. Credits: MESSENGER.

MESSENGER’s Mercury Laser Altimeter (MLA) will measure the topography or surface relief of the northern hemisphere of Mercury. That data will be used to create topographic maps, which will help characterize the geologic history of the planet. One of the most important tasks for MLA is to measure the depths of craters that are near Mercury’s north pole. In the latest “Science Highlights from Mercury’s Orbit,” MESSENGER’s Geophysics discipline group explains why.(read more)

Source: NASA News

Thickness Map of Buried Carbon-Dioxide Deposit.
Image credits: NASA/JPL-Caltech/Sapienza University of Rome/Southwest Research Institute.

NASA's Mars Reconnaissance Orbiter (MRO) has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet's axis varies. This process can affect the stability of liquid water if it exists on the Martian surface and increase the frequency and severity of Martian dust storms.

Researchers using MRO's ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet's south pole. The scientists suspect that much of this carbon dioxide enters the planet's atmosphere and swells the atmosphere's mass when Mars' tilt increases. The findings are published in a report in the journal Science.

The newly found deposit has a volume similar to Lake Superior's nearly 3,000 cubic miles. The deposit holds up to 80 percent as much carbon dioxide as today's Martian atmosphere. Collapse pits caused by dry ice sublimation and other clues suggest the deposit is in a dissipating phase, adding gas to the atmosphere each year. Mars' atmosphere is about 95 percent carbon dioxide, in contrast to Earth's much thicker atmosphere, which is less than .04 percent carbon dioxide. (read more)

Source: NASA News

Artist's concept of the magnetic connection between Saturn and its moon Enceladus. Image credit: NASA/JPL/JHUAPL/University of Colorado/Central Arizona College/SSI

NASA is releasing the first images and sounds of an electrical connection between Saturn and one of its moons. The data collected by the agency's Cassini spacecraft enable scientists to improve their understanding of the complex web of interaction between the planet and its numerous moons. The results of the data analysis are published in the journals Nature and Geophysical Research Letters.

Scientists previously theorized an electrical circuit should exist at Saturn. After analyzing data that Cassini collected in 2008, scientists saw a glowing patch of ultraviolet light emissions near Saturn's north pole that marked the presence of  a circuit, even though the moon is 150,000 miles (240,000 kilometers) away from the planet.

The patch occurs at the end of a magnetic field line connecting Saturn and its moon Enceladus. The area, known as an auroral footprint, is the spot where energetic electrons dive into the planet's atmosphere, following magnetic field lines that arc between the planet's north and south polar regions. (read more)

Source: MESSENGER Mission

One of the primary science goals of MESSENGER is to study Mercury’s very thin atmosphere, or exosphere. Although observations of the exosphere from orbit have begun, these data must be carefully calibrated, and analysis is still underway. In the meantime, Messenger Mission has launched a web primer on Mercury’s exosphere: what it is, how we observe it, and why it is important. (read more)

Source: Messenger Press Release

On April 4th, MESSENGER began its yearlong science campaign to understand the innermost planet. The spacecraft will fly around Mercury 700 times over the next 12 months, and its instruments will perform the first complete reconnaissance of the cratered planet’s geochemistry, geophysics, geological history, atmosphere, magnetosphere, and plasma environment.

“MESSENGER’s orbital commissioning phase, which we just completed, demonstrated that the spacecraft and payload are all operating nominally, notwithstanding Mercury’s challenging environment,” says Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. “With the beginning today of the primary science phase of the mission, we will be making nearly continuous observations that will allow us to gain the first global perspective on the innermost planet. Moreover, as solar activity steadily increases, we will have a front-row seat on the most dynamic magnetosphere–atmosphere system in the Solar System.”

MESSENGER’s 12-month orbital phase covers two Mercury solar days (one Mercury solar day, from sunrise to sunrise, is equal to 176 Earth days). This means that the spacecraft can view a given spot on the surface under given lighting conditions only twice during the mission, six months apart, making available observation time a precious resource. “So the surface mapping observations had to be planned for the entire year far in advance to ensure coverage of the entire planet under acceptable illumination and viewing geometries,” says MESSENGER Deputy Project Scientist Brian Anderson, who oversaw the planning for orbital operations.

SciBox – a suite of software tools for science observation simulation– was developed to help the team choreograph the complicated process of maximizing the scientific return from the mission and minimizing conflicts between instrument observations, while at the same time meeting all spacecraft constraints on pointing, data downlink rates, and onboard data storage capacity. The SciBox tool simulates the entire year of science observations and identifies the best times to take each type of observation. The commands for each week of observations are derived from this full mission analysis.

For instance, Anderson explains, “The remote sensing instruments to measure topography and determine surface and atmospheric composition are fixed on the spacecraft and share the same view direction. Because the ideal viewing directions for these instruments are not the same, we assigned altitude ranges for which the spacecraft pointing is optimized for the science from each instrument. The camera has its own pivot, so it has much greater freedom in viewing the surface and it takes pictures at all altitudes,” he continues. “Several other instruments make measurements of local properties, magnetic field, or charged particles and acquire excellent data regardless of the spacecraft pointing.”

SciBox works by finding the best opportunities for each of the instruments to make their measurements and then analyzing how those measurements contribute toward the science goals of the entire mission. “The SciBox tool allows us to plan thousands of science observation activities every week that have to be precisely timed with customized spacecraft pointing,” Anderson says.

The observations depend critically on where the spacecraft is in its orbit around Mercury, so the final science observation plan was not generated until the MESSENGER spacecraft completed Mercury orbit insertion. The software commands for this week’s instrument operations were sent to MESSENGER only last week.

“We had to wait until after MESSENGER was in orbit before we could start building the actual science sequences that start today, because we needed the actual in-orbit ephemeris as calculated by our navigation team to ensure that images and other pointed observations were taken where planned,” explains MESSENGER Payload Operations Manager Alice Berman.

On March 21, her team received the first ephemeris following Mercury orbit insertion, a delivery that provided less than two weeks for each instrument payload lead to generate inputs, test them, and deliver them to the mission operations team. That team then had to merge those science observation commands with the spacecraft operating commands and fully test the entire package.

For example, the command load for this week’s observations provides for the acquisition of 4,196 images by the Mercury Dual Imaging System (MDIS). The MDIS team had to check the commands governing each of those images; and the guidance and control team next had to run detailed software simulations on all the science guidance and control commands for the entire week and then add the non-science commands, such as those directing solar panel motions and star trackers. Finally the team re-simulated the full sequence again.

“It’s a tremendous amount of work and analysis that has to be done every week,” Berman notes. “From our experience with the In-the-Life exercises over the last two years, we determined that we would need three weeks for that process. But our entire team did an outstanding job getting it all done on the accelerated schedule.”

Imaging during the MESSENGER flybys provided important reconnaissance for the observations from orbit. During MESSENGER’s first six months in orbit, MDIS will create new, higher resolution, global maps of the planet in color and monochrome, acquired under near-ideal viewing conditions.

Emphasis during the second six months will shift to targeted, high-resolution imaging with the MDIS narrow-angle camera and acquisition of a second monochrome map but from a different viewing direction to allow stereoscopic analysis of topography. Additionally,

· The Mercury Laser Altimeter will measure the topography of the northern hemisphere over four Mercury years.

· The Gamma-Ray and Neutron Spectrometer and the X-Ray Spectrometer will yield global maps of elemental composition.

· The Magnetometer will measure the vector magnetic field under a range of solar distances and conditions.

· The Visible and Infrared Spectrograph will produce global maps of surface reflectance from which surface mineralogy can be inferred, and the Ultraviolet and Visible Spectrometer will produce time-dependent global maps of exospheric species abundances versus altitude.

· The Energetic Particle and Plasma Spectrometer will sample the plasma and energetic particle population in the solar wind, at major magnetospheric boundaries, and throughout the environment of Mercury at a range of solar distances and levels of solar activity.

· The radio science experiment will extend topographic information to the southern hemisphere by making occultation measurements of planet radius, and the planet’s obliquity and the amplitude of the physical libration will be determined independently from the topography and gravity field.

MESSENGER orbits Mercury twice every Earth day. Once a day, the spacecraft will stop making measurements and turn its antenna toward Earth for eight hours to send data back – via the Deep Space Network – to the MESSENGER Mission Operations Center at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

“The engineering teams accomplished an astonishing achievement by developing, launching, and guiding MESSENGER through the inner solar system and safely placing the spacecraft in orbit about Mercury” says Anderson. “Now the science planning teams are working hard to take full advantage of this unprecedented opportunity to learn everything we can about Earth’s heretofore enigmatic sibling planet. With thousands of science observation commands to plan, test, and verify every week, not to mention the need to verify that the observations are successful, we certainly have our work cut out for us,” Anderson says. “But we have the tools, the people, and the processes in place to do the job. So far, everything is going just the way we planned.”

Source: ESA

Neibouring volcanoes on Mars. Credits: ESA/DLR/FU Berlin (G. Neukum)

ESA’s Mars Express has returned images of mist-capped volcanoes located in the northern hemisphere of the red planet. Long after volcanic activity ceased, the area was transformed by meteor impacts that deposited ejected material over the lower flanks of the volcanoes. (read more)

Source: Messenger Mission

On March 17th, MESSENGER Mission Operations Center at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., received the anticipated radiometric signals confirming nominal burn shutdown and successful insertion of the MESSENGER probe into orbit around the planet Mercury.

The spacecraft rotated back to the Earth and started transmitting data.  Upon review of these data, the engineering and operations teams confirmed that the burn executed nominally with all subsystems reporting a clean burn and no logged errors.

MESSENGER’s main thruster fired for approximately 15 minutes  slowing the spacecraft by 1,929 miles per hour (862 meters per second) and easing it into the planned eccentric orbit about Mercury. The rendezvous took place about 96 million miles (155 million kilometers) from Earth.

Source: Mars Reconnaissance Orbiter

Area of about 460 meters across, in which carbonate minerals
have been identified from spectrometer observations.
Image credit: NASA/JPL-Caltech/Univ. of Arizona

Rocks on Mars dug from far underground by crater-blasting impacts are providing glimpses of one possible way Mars' atmosphere has become much less dense than it used to be.

At several places where cratering has exposed material from depths of about 5 kilometers (3 miles) or more beneath the surface, observations by a mineral-mapping instrument on NASA's Mars Reconnaissance Orbiter indicate carbonate minerals.

These are not the first detections of carbonates on Mars. However, compared to earlier findings, they bear closer resemblance to what some scientists have theorized for decades about the whereabouts of Mars' "missing" carbon. If deeply buried carbonate layers are found to be widespread, they would help answer questions about the disappearance of most of ancient Mars' atmosphere, which is deduced to have been thick and mostly carbon dioxide. The carbon that goes into formation of carbonate minerals can come from atmospheric carbon dioxide. (read more)

Source: NASA News

NASA will host a media teleconference to discuss the first spacecraft to orbit Mercury.

NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging, or MESSENGER, will enter orbit at approximately 9 p.m. EDT on Thursday, March 17. The spacecraft has conducted more than a dozen laps through the inner solar system for nearly 7 years.

Media teleconference participants are:
-- Andy Calloway, MESSENGER mission operations manager, Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md.
-- Carl Engelbrecht, MESSENGER propulsion subsystem lead, APL
-- Sean Solomon, MESSENGER principal investigator, Carnegie Institution of Washington

Source: ESA

Impact crater South of the Huyghens Crater that measures 78 km in length,
opens from just under 10 km wide at one end to 25 km wide at the other, and
reaches a depth of 2 km. Image credit: ESA/DLR/FU Berlin (G. Neukum).

ESA's Mars Express has returned new images of an elongated impact crater in the southern hemisphere of Mars. Located just south of the Huygens basin, it could have been carved out by a train of projectiles striking the planet at a shallow angle. (read more)



Children from St Cronans Stargazers draw moon phases

The Big Moon Ball Project – A work in progress

The Moon? The Moon? How on Earth do you explain the Moon to small children?  In many other talks I had done so in graphic from and with images but wanted to try something different. I figured I would have a go at an interactive workshop in a field, as one would of course.

Made me a Moon ball and put it on a stand, borrowed a super two million candle torch, put it on a stand.  Then I invited my new astronomy group St Cronans Stargazers to join me at our usual place.  As it was midterm a small but smiling group turned up, perfect for a first run!  We pretended the torch was the sun and the children were the Earth and I became the Moon.  For the first orbit of the Earth I spoke about the phase they see from the Earth as they looked at me (the Moon Ball) moving from New to First Quarter, then Full, then Last Quarter, then back to New.

The children got the idea very quickly as the sun (torch) illuminated the phases while they (the Earth) turned in unison in the field at the end of my road. The Big Moon Ball beamed the moons phases into their eyes.  Clip boards and paper were provided for the second orbit of the Earth .The children sketched the four main Moon phases as they happened and wrote down the names. The parents were very helpful, standing at the points of the phases and also helping the children see their clipboards and their drawings in the dark.

Of course this workshop would be so much more powerful if the Moon was in the sky at the same time. I am continuing to develop the activity; it suits the Irish cloudy sky syndrome and is also an indoor workshop.  Every child wanted to hold the Moon Ball and help put it in the car afterwards. A whole bunch of fun was over in a blink the children had lovely practical drawings for their folders, and were on their way to understanding the Moons movements.

The Big Moon Ball Project was welcomed by Engineers Ireland as part of Engineers Week Ireland
Huge thanks to my husband Bernard for help with the sun and for taking the photographs.
The Moon Ball is getting an upgrade, the far side is being painted in now and the near side is developing more details, craters, rays and mountains.  More images on my website here

Cool News /  Hot Stuff

NASA Solar System Exploration Page I am really delighted and honoured to have  my Solar Dynamics Observatory  inspired painting on the site for the month of March ,check it out. !!

Deirdre Kelleghan

Source: NASA/Messenger

Solar System Family Portrait from the inside out. Image credit: NASA/John Hopkins
University Applied Physics Laboratory/Carnegie Institution of Washington

The MESSENGER spacecraft has captured the first portrait of our Solar System from the inside looking out. Comprised of 34 images, the mosaic provides a complement to the Solar System portrait – that one from the outside looking in – taken by Voyager 1 in 1990.

“Obtaining this portrait was a terrific feat by the MESSENGER team,” says MESSENGER Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. “This snapshot of our neighborhood also reminds us that Earth is a member of a planetary family that was formed by common processes four and a half billion years ago. Our spacecraft is soon to orbit the innermost member of the family, one that holds many new answers to how Earth-like planets are assembled and evolve.”

MESSENGER’s Wide Angle Camera (WAC) captured the images on November 3 and 16, 2010. In the mosaic, all of the planets are visible except for Uranus and Neptune, which – at distances of 3.0 and 4.4 billion kilometers – were too faint to detect. Earth’s Moon and Jupiter’s Galilean satellites (Callisto, Ganymede, Europa, and Io) can be seen in the NAC image insets. The Solar System’s perch on a spiral arm of the Milky Way galaxy also afforded a beautiful view of a portion of the galaxy in the bottom center.

“The curved shape of the mosaic is due to the inclination of MESSENGER’s orbit from the ecliptic, the plane in which Earth and most planets orbit, which means that the cameras must point up to see some planets and down to see others,” explains MESSENGER imaging team member Brett Denevi of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. “ The images are stretched to make it easier to detect the planets, though this stretch also highlights light scattered off of the planet limbs, and in some cases creates artifacts such as the non-spherical shape of some planets.”(read more)

Credit: Messenger Team

Image credit: NASA/Messenger.

After more than a dozen laps through the inner solar system, NASA's MESSENGER spacecraft will move into orbit around Mercury on March 17, 2011. The durable spacecraft — carrying seven science instruments and fortified against the blistering environs near the Sun — will be the first to orbit the innermost planet.

At 13:45 p.m. GMT, MESSENGER — having pointed its largest thruster very close to the direction of travel — will fire that thruster for nearly 14 minutes, with other thrusters firing for an additional minute, slowing the spacecraft by 862 meters per second (1,929 miles per hour) and consuming 31% of the propellant that the spacecraft carried at launch. Less than 9.5% of the usable propellant at the start of the mission will remain after completing the orbit insertion maneuver, but the spacecraft will still have plenty of propellant for future orbit correction maneuvers.

The orbit insertion will place the spacecraft into an initial orbit about Mercury that has a 200 kilometer (124 mile) minimum altitude and a period of 12 hours. At the time of orbit insertion, MESSENGER will be 46.14 million kilometers (28.67 million miles) from the Sun and 155.06 million kilometers (96.35 million miles) from Earth.

“The journey since launch, more than six and a half years ago, has been a long one,” says MESSENGER Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. “But we have rounded the last turn, and the finish line for the mission’s cruise phase is in sight. The team is ready for orbital operations to begin.”

Engineers recently tested the arrayed-antenna configuration that will be used during the Mercury orbit insertion. During the maneuver, MESSENGER’s orientation will be optimized to support the burn, not to support communications with the team on the ground. As a result, the signal home will be weaker than usual. To boost the signal, communications engineers will use four antennas at the Goldstone Deep Space Communications Complex — one 70-meter dish and three 34-meter dishes.

“This arrangement is not typical for a maneuver, so we wanted to do a few dry runs before orbit insertion,” says MESSENGER Communications Engineer Dipak Srinivasan, of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. “We are still analyzing the data, but everything went as expected.”

Since the last deep-space maneuver (DSM) almost a year and a half ago, the primary focus of the team has been on preparing for the orbit insertion maneuver and for orbital operations.  Detailed plans have been developed and vetted through an extensive series of meetings ranging from internal peer reviews of each subsystem to formal reviews with external experts assessing overall readiness. Three of the major reviews were dedicated specifically to the activities associated with the MOI maneuver itself.

In addition to taking advantage of planned DSMs to practice aspects of the orbit insertion maneuver, the team has conducted a number of flight tests to characterize key subsystem behavior and to confirm the proper operation of various spacecraft components.  Three full-team rehearsals using the hardware simulator have been conducted to practice all activities to be followed during the upcoming maneuver. The first of these exercises mimicked a nominal orbit insertion, and the following two presented anomalies for the team to recognize, analyze, and address.

“Although we feel that the preparations to date – and those scheduled for the next month – have been well thought-out, that the decisions made to define the specific activities were sound, and that the level of review and rehearsal has been more than adequate, we recognize the extraordinary complexity and unique nature of this endeavor,” says APL’s Peter Bedini, MESSENGER’s project manager. “But at this point, four weeks out, we are well positioned for success.  The spacecraft is healthy, continues to operate nominally, and is on course to be at the right place at the right time at 8:45 P.M. ET on the evening of March 17.”