Dawn Update: Ceres In All of Its Icy, Tilted Glory...

NASA / JPL - Caltech / UCLA / MPS / DLR / IDA

Ice in Ceres' Shadowed Craters Linked to Tilt History (News Release)

Dwarf planet Ceres may be hundreds of millions of miles from Jupiter, and even farther from Saturn, but the tremendous influence of gravity from these gas giants has an appreciable effect on Ceres' orientation. In a new study, researchers from NASA's Dawn mission calculate that the axial tilt of Ceres -- the angle at which it spins as it journeys around the Sun -- varies widely over the course of about 24,500 years. Astronomers consider this to be a surprisingly short period of time for such dramatic deviations.

Changes in axial tilt, or "obliquity," over the history of Ceres are related to the larger question of where frozen water can be found on Ceres' surface, scientists report in the journal Geophysical Research Letters. Given conditions on Ceres, ice would only be able to survive at extremely cold temperatures -- for example, in areas that never see the Sun.

"We found a correlation between craters that stay in shadow at maximum obliquity, and bright deposits that are likely water ice," said Anton Ermakov, postdoctoral researcher at NASA's Jet Propulsion Laboratory, Pasadena, California, and lead author of the study. "Regions that never see sunlight over millions of years are more likely to have these deposits."

Cycles of Obliquity

Throughout the last 3 million years, Ceres has gone through cycles where its tilt ranges from about 2 degrees to about 20 degrees, calculations indicate.

"We cannot directly observe the changes in Ceres' orientation over time, so we used the Dawn spacecraft's measurements of shape and gravity to precisely reconstruct what turned out to be a dynamic history," said Erwan Mazarico, a co-author at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The last time the dwarf planet reached a maximum tilt, which was about 19 degrees, was 14,000 years ago, researchers said. For comparison, Earth is tilted 23.5 degrees. This significant tilt causes our planet to experience seasons: The northern hemisphere experiences summer when it is oriented toward the Sun, and winter when it's pointed away from the Sun. By contrast, Ceres' current tilt is about 4 degrees, so it will not have such strong seasonal effects over the course of a year there (which is about 4.6 Earth years).

How Obliquity Relates to Ice

When the axial tilt is small, relatively large regions on Ceres never receive direct sunlight, particularly at the poles. These persistently shadowed regions occupy an area of about 800 square miles (2,000 square kilometers). But when the obliquity increases, more of the craters in the polar regions receive direct exposure to the Sun, and persistently shadowed areas only occupy 0.4 to 4 square miles (1 to 10 square kilometers). These areas on Ceres' surface, which stay in shadow even at high obliquity, may be cold enough to maintain surface ice, Dawn scientists said.

These craters with areas that stay in shadow over long periods of time are called "cold traps," because they are so cold and dark that volatiles -- substances easily vaporized -- that migrate into these areas can't escape, even over a billion years. A 2016 study by the Dawn team in Nature Astronomy found bright material in 10 of these craters, and data from Dawn's visible and infrared mapping spectrometer indicate that one of them contains ice.

The new study focused on polar craters and modeled how shadowing progresses as Ceres' axial tilt varies. In the northern hemisphere, only two persistently shadowed regions remain in shadow at the maximum 20-degree tilt. Both of these regions have bright deposits today. In the southern hemisphere, there are also two persistently shadowed regions at highest obliquity, and one of them clearly has a bright deposit.

Shadowed Regions in Context

Ceres is the third body in the solar system found to have permanently shadowed regions. Mercury and Earth's Moon are the other two, and scientists believe they received their ice from impacting bodies. However, Mercury and the Moon do not have such wide variability in their tilts because of the stabilizing gravitational influence of the Sun and Earth, respectively. The origin of the ice in Ceres' cold traps is more mysterious -- it may come from Ceres itself, or may be delivered by impacts from asteroids and comets. Regardless, the presence of ice in cold traps could be related to a tenuous water atmosphere, which was detected by ESA's Herschel Space Observatory in 2012-13. Water molecules that leave the surface would fall back onto Ceres, with some landing in cold traps and accumulating there.

"The idea that ice could survive on Ceres for long periods of time is important as we continue to reconstruct the dwarf planet's geological history, including whether it has been giving off water vapor," said Carol Raymond, deputy principal investigator of the Dawn mission and study co-author, based at JPL.

Dawn's mission is managed by JPL for NASA'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, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

Source: Jet Propulsion Laboratory

Photos of the Day: I Dig the Shamrock Shake...

Happy St. Patrick's Day! Just thought I'd share these photos that I took of the Shamrock Shake that I bought at McDonald's a little over two weeks ago. It's totally delicious! I've been meaning to try out this minty beverage since 2012...but was unable to due to this unfortunate situation that I was in during March of that year. Well, better late than never!

An Update on Europe's Upcoming Jupiter Mission...Set to Launch in 2022

ESA / AOESImage

ESA’s Jupiter Mission Moves Off the Drawing Board (Press Release)

Demanding electric, magnetic and power requirements, harsh radiation, and strict planetary protection rules are some of the critical issues that had to be tackled in order to move ESA’s Jupiter Icy Moons Explorer – Juice – from the drawing board and into construction.

Scheduled for launch in 2022, with arrival in the Jovian system in 2029, Juice will spend three-and-a-half years examining the giant planet’s turbulent atmosphere, enormous magnetosphere, its set of tenuous dark rings and its satellites.

It will study the large icy moons Ganymede, Europa and Callisto, which are thought to have oceans of liquid water beneath their icy crusts – perhaps even harbouring habitable environments.

The mission will culminate in a dedicated, eight-month tour around Ganymede, the first time any moon beyond our own has been orbited by a spacecraft.

Juice will be equipped with 10 state-of-the-art instruments, including cameras, an ice-penetrating radar, an altimeter, radio-science experiments, and sensors to monitor the magnetic fields and charged particles in the Jovian system.

In order to ensure it can address these goals in the challenging Jovian environment, the spacecraft’s design has to meet stringent requirements.

An important milestone was reached earlier this month, when the preliminary design of Juice and its interfaces with the scientific instruments and the ground stations were fixed, which will now allow a prototype spacecraft to be built for rigorous testing.

The review also confirmed that the 5.3 tonne spacecraft will be compatible with its Ariane 5 launcher.

Operating in the outer Solar System, far from the Sun, means that Juice needs a large solar array: two wings of five panels each are foreseen, which will cover a total surface area of nearly 100 square metres, capable of providing 820 Watts at Jupiter by the end of the mission.

After launch, Juice will make five gravity-assist flybys in total: one each at Mars and Venus, and three at Earth, to set it on course for Jupiter. Its solar panels will have to cope with a range of temperatures such that when it is flying closer to the Sun during the Venus flyby, the solar wings will be tilted to avoid excessive temperatures damaging the solar cells.

The spacecraft’s main engine will be used to enter orbit around the giant planet, and later around Jupiter’s largest moon, Ganymede. As such, the engine design has also been critically reviewed at this stage.

Special measures will allow Juice to cope with the extremely harsh radiation that it must endure for several years around Jupiter. This means careful selection of components and materials, as well as radiation shielding.

One particularly important topic is Juice’s electromagnetic ‘cleanliness’. Because a key goal is to monitor the magnetic fields and charged particles at Jupiter, it is imperative that any electromagnetic fields generated by the spacecraft itself do not interfere with the sensitive scientific measurements.

This will be achieved by the careful design of the solar array electrical architecture, the power distribution unit, and the reaction wheels – a type of flywheel that stabilises the attitude.

The review also ensured that Juice will meet strict planetary protection guidelines, because it is imperative to minimise the risk that the potentially habitable ocean moons, particularly Europa, might be contaminated by viruses, bacteria or spores carried by the spacecraft from Earth. Therefore, mission plans ensure that Juice will not crash into Europa, on a timescale of hundreds of years.

“The spacecraft design has been extensively and positively reviewed, and confirmed to address the many critical mission requirements,” says Giuseppe Sarri, Juice project manager. “So far we are on schedule, and are delighted to begin the development stage of this ambitious large-class mission.”

ESA’s industrial partners, led by Airbus, now have the go-ahead to start building the prototype spacecraft units that will subjected to tough tests to simulate the conditions expected during launch, as well as the extreme range of environmental conditions.

Once the design is proved beyond doubt, the flight model – the one that will actually go into space – will be built.

Source: European Space Agency

Photos of the Day: A Book Signing at The Grove in LA...

Yesterday, I went to The Grove near Beverly Hills to attend a discussion and book signing by Lily Collins...the daughter of music legend Phil Collins and an up-and-coming actress who appeared in such films as last year's Rules Don't Apply, 2013's The Mortal Instruments: City of Bones and the 2009 Oscar-nominated movie The Blind Side. Ms. Collins was totally awesome in person. She read an excerpt from her new book Unfiltered before giving her take on it and talking about what motivated her to write her first publication. Afterwards, she spent the next two hours signing copies of her book and taking pics with around 300 fans who drove to Barnes & Noble to see her in person. Some attendees even flew 2,000 miles to see Ms. Collins in Los Angeles... Pretty cool!



There are two other book signings that I plan to attend this May—but I won't mention the people appearing since I don't want to jinx these events. Carry on!

Cassini Update: Stunning Images of a "Ravioli World"...

NASA / JPL - Caltech / Space Science Institute

Cassini Reveals Strange Shape of Saturn's Moon Pan (Press Release - March 9)

These raw, unprocessed images of Saturn's tiny moon, Pan, were taken on March 7, 2017, by NASA's Cassini spacecraft. The flyby had a close-approach distance of 24,572 kilometers (15,268 miles).

These images are the closest images ever taken of Pan and will help to characterize its shape and geology.

Additional raw images from Cassini are available at:

https://saturn.jpl.nasa.gov/galleries/raw-images

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the mission for the agency's Science Mission Directorate in Washington. The Cassini imaging operations center is based at the Space Science Institute in Boulder, Colorado. Caltech in Pasadena manages JPL for NASA.

Source: Jet Propulsion Laboratory

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NASA / JPL - Caltech / Space Science Institute

It's Official: The Europa Clipper Mission Is Now Called...The Europa Clipper!

NASA / JPL - Caltech

NASA Mission Named 'Europa Clipper' (News Release)

NASA's upcoming mission to investigate the habitability of Jupiter's icy moon Europa now has a formal name: Europa Clipper.

The moniker harkens back to the clipper ships that sailed across the oceans of Earth in the 19th century. Clipper ships were streamlined, three-masted sailing vessels renowned for their grace and swiftness. These ships rapidly shuttled tea and other goods back and forth across the Atlantic Ocean and around globe.

In the grand tradition of these classic ships, the Europa Clipper spacecraft would sail past Europa at a rapid cadence, as frequently as every two weeks, providing many opportunities to investigate the moon up close. The prime mission plan includes 40 to 45 flybys, during which the spacecraft would image the moon's icy surface at high resolution and investigate its composition and the structure of its interior and icy shell.

Europa has long been a high priority for exploration because it holds a salty liquid water ocean beneath its icy crust. The ultimate aim of Europa Clipper is to determine if Europa is habitable, possessing all three of the ingredients necessary for life: liquid water, chemical ingredients, and energy sources sufficient to enable biology.

"During each orbit, the spacecraft spends only a short time within the challenging radiation environment near Europa. It speeds past, gathers a huge amount of science data, then sails on out of there," said Robert Pappalardo, Europa Clipper project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.

Previously, when the mission was still in the conceptual phase, it was sometimes informally called Europa Clipper, but NASA has now adopted that name as the former title for the mission.

The mission is being planned for launch in the 2020s, arriving in the Jupiter system after a journey of several years.

JPL manages the mission for the agency's Science Mission Directorate in Washington.

Source: NASA.Gov

Send Your Artwork Into Space Aboard NASA's Next Exoplanet-Hunting Mission!

NASA / Goddard Space Flight Center

Just thought I'd end this month by pointing out that NASA is currently inviting the public to submit artwork (via e-mail) that will fly aboard the Transiting Exoplanet Survey Satellite (TESS)...which is scheduled to launch aboard SpaceX's Falcon 9 rocket from Florida in March of 2018. Click on this page for more details. Right now, there is no limit as to how many artwork you can submit to fly aboard TESS; this campaign either ends on November 20, 2017, or when the drive (Hard drive? Flash drive? The site doesn't say—though it's most likely the latter) that will carry the submissions reaches full capacity. The artwork below are the ones that I myself sent in as of today. I created a couple of more illustrations that I plan to submit over the next few weeks... I'll post them in a future Blog entry. If you have your own drawings to send into the cosmos, submit now!

Lakers Update: Jim Buss (and Mitch Kupchak) Finally Gets the Boot...

Getty Images

Lakers Name Earvin "Magic" Johnson President of Basketball Operations (Press Release - February 21)

Magic to run Lakers Basketball Front Office as part of restructuring.

LOS ANGELES -- Los Angeles Lakers Governor Jeanie Buss announced today that the team has named Earvin "Magic" Johnson as President of Basketball Operations. In addition, General Manager Mitch Kupchak has been relieved of his duties, effective immediately. Furthermore, Jim Buss will no longer hold his role as Lakers Executive Vice President of Basketball Operations.

"Today I took a series of actions I believe will return the Lakers to the heights Dr. Jerry Buss demanded and our fans rightly expect," Jeanie Buss said. "Effective immediately, Earvin Johnson will be in charge of all basketball operations and will report directly to me. Our search for a new General Manager to work with Earvin and Coach Luke Walton is well underway and we hope to announce a new General Manager in short order. Together, Earvin, Luke and our new General Manager will establish the foundation for the next generation of Los Angeles Lakers greatness."

"It's a dream come true to return to the Lakers as President of Basketball Operations working closely with Jeanie Buss and the Buss family," said Earvin "Magic" Johnson. "Since 1979, I've been a part of the Laker Nation and I'm passionate about this organization. I will do everything I can to build a winning culture on and off the court. We have a great coach in Luke Walton and good young players. We will work tirelessly to return our Los Angeles Lakers to NBA champions."

Jeanie Buss added, "I took these actions today to achieve one goal: Everyone associated with the Lakers will now be pulling in the same direction, the direction established by Earvin and myself. We are determined to get back to competing to win NBA championships again."

Regarding Mitch Kupchak, Jeanie Buss stated, "We are grateful for the many contributions Mitch has made to the Lakers over the years and we wish him all the best."

With regard to fellow owner and brother, Jim Buss, Ms. Buss said, "Jim loves the Lakers. Although he will no longer be responsible for basketball personnel decisions, he is an owner of this team and we share the same goal: returning the Lakers to the level of greatness our father demanded. Our fans deserve no less."

In addition to the changes made within the basketball department, the Lakers also announced they have parted ways with John Black who had been the Lakers Vice President of Public Relations. Chief Operating Officer Tim Harris will immediately begin a search for a replacement. Jeanie Buss added, "We thank John for his many years of service."

Source: Lakers.com

(Three Earth-Like Worlds with Liquid Water on Them? Yes, Please!) NASA Announces a Stellar Exoplanet Discovery...

NASA / JPL - Caltech

NASA Telescope Reveals Largest Batch of Earth-Size, Habitable-Zone Planets Around Single Star (Press Release)

NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.

The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system. All of these seven planets could have liquid water – key to life as we know it – under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.

“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”

At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets.

This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system. Assisted by several ground-based telescopes, including the European Southern Observatory's Very Large Telescope, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

The new results were published Wednesday in the journal Nature, and announced at a news briefing at NASA Headquarters in Washington.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them, allowing their density to be estimated.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces. The mass of the seventh and farthest exoplanet has not yet been estimated – scientists believe it could be an icy, "snowball-like" world, but further observations are needed.

"The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star," said Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, Belgium. "It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds."

In contrast to our sun, the TRAPPIST-1 star – classified as an ultra-cool dwarf – is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun. The planets also are very close to each other. If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth's sky.

The planets may also be tidally locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong winds blowing from the day side to the night side, and extreme temperature changes.

Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. In the fall of 2016, Spitzer observed TRAPPIST-1 nearly continuously for 500 hours. Spitzer is uniquely positioned in its orbit to observe enough crossing – transits – of the planets in front of the host star to reveal the complex architecture of the system. Engineers optimized Spitzer’s ability to observe transiting planets during Spitzer’s “warm mission,” which began after the spacecraft’s coolant ran out as planned after the first five years of operations.

"This is the most exciting result I have seen in the 14 years of Spitzer operations," said Sean Carey, manager of NASA's Spitzer Science Center at Caltech/IPAC in Pasadena, California. "Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets.”

Following up on the Spitzer discovery, NASA's Hubble Space Telescope has initiated the screening of four of the planets, including the three inside the habitable zone. These observations aim at assessing the presence of puffy, hydrogen-dominated atmospheres, typical for gaseous worlds like Neptune, around these planets.

In May 2016, the Hubble team observed the two innermost planets, and found no evidence for such puffy atmospheres. This strengthened the case that the planets closest to the star are rocky in nature.

"The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets," said Nikole Lewis, co-leader of the Hubble study and astronomer at the Space Telescope Science Institute in Baltimore, Maryland. NASA's planet-hunting Kepler space telescope also is studying the TRAPPIST-1 system, making measurements of the star's minuscule changes in brightness due to transiting planets. Operating as the K2 mission, the spacecraft's observations will allow astronomers to refine the properties of the known planets, as well as search for additional planets in the system. The K2 observations conclude in early March and will be made available on the public archive.

Spitzer, Hubble, and Kepler will help astronomers plan for follow-up studies using NASA's upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone, and other components of a planet's atmosphere. Webb also will analyze planets' temperatures and surface pressures – key factors in assessing their habitability.

NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate. Science operations are conducted at the Spitzer Science Center, at Caltech, in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at Caltech/IPAC. Caltech manages JPL for NASA.

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NASA / JPL - Caltech

NASA Is A Step Closer To Launching a Probe To Study One Of Jupiter's Ocean-Bearing Moons...

NASA / JPL - Caltech

NASA's Europa Flyby Mission Moves into Design Phase (News Release)

A mission to examine the habitability of Jupiter's ocean-bearing moon Europa is taking one step closer to the launch pad, with the recent completion of a major NASA review.

On Feb. 15, NASA's Europa multiple-flyby mission successfully completed its Key Decision Point-B review. This NASA decision permits the mission to move forward into its preliminary design phase, known as "Phase B," beginning on Feb. 27.

A highlight of Phase A was the selection and accommodation of 10 instruments being developed to study the scientific mysteries of Europa. The new mission phase is planned to continue through September 2018, and will result in the completion of a preliminary design for the mission's systems and subsystems. Some testing of spacecraft components, including solar cells and science instrument detectors, has already been underway during Phase A, and this work is planned to continue into Phase B.

In addition, during Phase B subsystem vendors will be selected, as well as prototype hardware elements for the science instruments. Spacecraft subassemblies will be built and tested as well.

The Europa mission spacecraft is being planned for launch in the 2020s, arriving in the Jupiter system after a journey of several years. The spacecraft would orbit Jupiter as frequently as every two weeks, providing many opportunities for close flybys of Europa. The mission plan includes 40 to 45 flybys in the prime mission, during which the spacecraft would image the moon's icy surface at high resolution and investigate its composition and the structure of its interior and icy shell.

The life cycle of a NASA science mission includes several key phases. At each step, missions must successfully demonstrate that they have met the agency's requirements in order to indicate readiness to move forward into the next phase. Phase B includes preliminary design work, while phases C and D include final design, spacecraft fabrication, assembly and testing, and launch.

Source: NASA.Gov