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Wednesday, May 31, 2017

SOLAR PROBE PLUS Gets a New Name...

An artist's concept of NASA's Parker Solar Probe spacecraft approaching the Sun.
JHU / APL

NASA Renames Solar Probe Mission to Honor Pioneering Physicist Eugene Parker (News Release)

NASA has renamed the Solar Probe Plus spacecraft — humanity’s first mission to a star, which will launch in 2018 — as the Parker Solar Probe in honor of astrophysicist Eugene Parker. The announcement was made at a ceremony at the University of Chicago, where Parker serves as the S. Chandrasekhar Distinguished Service Professor Emeritus, Department of Astronomy and Astrophysics.

In 1958, Parker — then a young professor at the university’s Enrico Fermi Institute — published an article in the Astrophysical Journal called “Dynamics of the interplanetary gas and magnetic fields.” Parker believed there was high speed matter and magnetism constantly escaping the Sun, and that it affected the planets and space throughout our solar system.

This phenomenon, now known as the solar wind, has been proven to exist repeatedly through direct observation. Parker’s work forms the basis for much of our understanding about how stars interact with the worlds that orbit them.

“This is the first time NASA has named a spacecraft for a living individual,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington. “It’s a testament to the importance of his body of work, founding a new field of science that also inspired my own research and many important science questions NASA continues to study and further understand every day. I’m very excited to be personally involved honoring a great man and his unprecedented legacy.”

“The solar probe is going to a region of space that has never been explored before,” said Parker. “It’s very exciting that we’ll finally get a look. One would like to have some more detailed measurements of what’s going on in the solar wind. I’m sure that there will be some surprises. There always are.”

In the 1950s, Parker proposed a number of concepts about how stars — including our Sun — give off energy. He called this cascade of energy the solar wind, and he described an entire complex system of plasmas, magnetic fields and energetic particles that make up this phenomenon. Parker also theorized an explanation for the superheated solar atmosphere, the corona, which is — contrary to what was expected by physics laws — hotter than the surface of the Sun itself. Many NASA missions have continued to focus on this complex space environment defined by our star — a field of research known as heliophysics.

“Parker Solar Probe is going to answer questions about solar physics that we’ve puzzled over for more than six decades,” said Parker Solar Probe Project Scientist Nicola Fox, of the Johns Hopkins University Applied Physics Laboratory. “It’s a spacecraft loaded with technological breakthroughs that will solve many of the largest mysteries about our star, including finding out why the Sun’s corona is so much hotter than its surface. And we’re very proud to be able to carry Gene’s name with us on this amazing voyage of discovery.”

NASA missions are most often renamed after launch and certification; in this case, given Parker’s accomplishments within the field, and how closely aligned this mission is with his research, the decision was made to honor him prior to launch, in order to draw attention to his important contributions to heliophysics and space science.

Born on June 10, 1927, in Michigan, Eugene Newman Parker received a Bachelor of Science in physics from Michigan State University and a doctorate from Caltech. He then taught at the University of Utah, and since 1955, Parker has held faculty positions at the University of Chicago and at its Fermi Institute. He has received numerous awards for his research, including the George Ellery Hale Prize, the National Medal of Science, the Bruce Medal, the Gold Medal of the Royal Astronomical Society, the Kyoto Prize, and the James Clerk Maxwell Prize.

Parker Solar Probe is on track for launch during a 20-day window that opens July 31, 2018. The mission is part of NASA’s Living With a Star program to explore aspects of the Sun-Earth system that directly affect life and society. LWS is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington, D.C. Johns Hopkins APL manages the mission for NASA and is designing and building and will operate the spacecraft.

Source: NASA.Gov

Thursday, May 25, 2017

Juno Update: Learning Something New About a Jovian World...

An image of Jupiter's south pole as seen by NASA's Juno spacecraft...from 32,000 miles (52,000 kilometers) away.
NASA / JPL - Caltech / SwRI / MSSS / Betsy Asher Hall / Gervasio Robles

A Whole New Jupiter: First Science Results from NASA’s Juno Mission (Press Release)

Early science results from NASA’s Juno mission to Jupiter portray the largest planet in our solar system as a complex, gigantic, turbulent world, with Earth-sized polar cyclones, plunging storm systems that travel deep into the heart of the gas giant, and a mammoth, lumpy magnetic field that may indicate it was generated closer to the planet’s surface than previously thought.

“We are excited to share these early discoveries, which help us better understand what makes Jupiter so fascinating,” said Diane Brown, Juno program executive at NASA Headquarters in Washington. "It was a long trip to get to Jupiter, but these first results already demonstrate it was well worth the journey.”

Juno launched on Aug. 5, 2011, entering Jupiter’s orbit on July 4, 2016. The findings from the first data-collection pass, which flew within about 2,600 miles (4,200 kilometers) of Jupiter's swirling cloud tops on Aug. 27, are being published this week in two papers in the journal Science, as well as 44 papers in Geophysical Research Letters.

“We knew, going in, that Jupiter would throw us some curves,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “But now that we are here we are finding that Jupiter can throw the heat, as well as knuckleballs and sliders. There is so much going on here that we didn’t expect that we have had to take a step back and begin to rethink of this as a whole new Jupiter.”

Among the findings that challenge assumptions are those provided by Juno’s imager, JunoCam. The images show both of Jupiter's poles are covered in Earth-sized swirling storms that are densely clustered and rubbing together.

“We're puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn't look like the south pole,” said Bolton. “We're questioning whether this is a dynamic system, and are we seeing just one stage, and over the next year, we're going to watch it disappear, or is this a stable configuration and these storms are circulating around one another?”

Another surprise comes from Juno’s Microwave Radiometer (MWR), which samples the thermal microwave radiation from Jupiter’s atmosphere, from the top of the ammonia clouds to deep within its atmosphere. The MWR data indicates that Jupiter’s iconic belts and zones are mysterious, with the belt near the equator penetrating all the way down, while the belts and zones at other latitudes seem to evolve to other structures. The data suggest the ammonia is quite variable and continues to increase as far down as we can see with MWR, which is a few hundred miles or kilometers.

Prior to the Juno mission, it was known that Jupiter had the most intense magnetic field in the solar system. Measurements of the massive planet’s magnetosphere, from Juno’s magnetometer investigation (MAG), indicate that Jupiter’s magnetic field is even stronger than models expected, and more irregular in shape. MAG data indicates the magnetic field greatly exceeded expectations at 7.766 Gauss, about 10 times stronger than the strongest magnetic field found on Earth.

“Juno is giving us a view of the magnetic field close to Jupiter that we’ve never had before,” said Jack Connerney, Juno deputy principal investigator and the lead for the mission’s magnetic field investigation at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “Already we see that the magnetic field looks lumpy: it is stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action closer to the surface, above the layer of metallic hydrogen. Every flyby we execute gets us closer to determining where and how Jupiter’s dynamo works.”

Juno also is designed to study the polar magnetosphere and the origin of Jupiter's powerful auroras—its northern and southern lights. These auroral emissions are caused by particles that pick up energy, slamming into atmospheric molecules. Juno’s initial observations indicate that the process seems to work differently at Jupiter than at Earth.

Juno is in a polar orbit around Jupiter, and the majority of each orbit is spent well away from the gas giant. But, once every 53 days, its trajectory approaches Jupiter from above its north pole, where it begins a two-hour transit (from pole to pole) flying north to south with its eight science instruments collecting data and its JunoCam public outreach camera snapping pictures. The download of six megabytes of data collected during the transit can take 1.5 days.

“Every 53 days, we go screaming by Jupiter, get doused by a fire hose of Jovian science, and there is always something new,” said Bolton. “On our next flyby on July 11, we will fly directly over one of the most iconic features in the entire solar system -- one that every school kid knows -- Jupiter’s Great Red Spot. If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno and her cloud-piercing science instruments.”

NASA's Jet Propulsion Laboratory in Pasadena, California, manages the Juno mission for NASA. The principal investigator is Scott Bolton of the Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate. Lockheed Martin Space Systems, in Denver, built the spacecraft.

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Jupiter's ring as seen by NASA's Juno spacecraft on August 27, 2016.
NASA / JPL - Caltech / SwRI

Wednesday, May 24, 2017

Getting Psyched Up Over Psyche's Earlier Launch Date...

An artist's concept of NASA's Psyche spacecraft studying a metal asteroid with the same name.
NASA / JPL - Caltech / Arizona State Univ. / Space Systems Loral / Peter Rubin

NASA Moves Up Launch of Psyche Mission to a Metal Asteroid (News Release)

Psyche, NASA's Discovery Mission to a unique metal asteroid, has been moved up one year with launch in the summer of 2022, and with a planned arrival at the main belt asteroid in 2026 -- four years earlier than the original timeline.

“We challenged the mission design team to explore if an earlier launch date could provide a more efficient trajectory to the asteroid Psyche, and they came through in a big way,” said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington. “This will enable us to fulfill our science objectives sooner and at a reduced cost.”

The Discovery program announcement of opportunity had directed teams to propose missions for launch in either 2021 or 2023. The Lucy mission was selected for the first launch opportunity in 2021, and Psyche was to follow in 2023. Shortly after selection in January, NASA gave the direction to the Psyche team to research earlier opportunities.

"The biggest advantage is the excellent trajectory, which gets us there about twice as fast and is more cost effective," said Principal Investigator Lindy Elkins-Tanton of Arizona State University in Tempe. "We are all extremely excited that NASA was able to accommodate this earlier launch date. The world will see this amazing metal world so much sooner."

The revised trajectory is more efficient, as it eliminates the need for an Earth gravity assist, which ultimately shortens the cruise time. In addition, the new trajectory stays farther from the Sun, reducing the amount of heat protection needed for the spacecraft. The trajectory will still include a Mars gravity assist in 2023.

"The change in plans is a great boost for the team and the mission," said Psyche Project Manager Henry Stone at NASA's Jet Propulsion Laboratory, Pasadena, California. "Our mission design team did a fantastic job coming up with this ideal launch opportunity."

The Psyche spacecraft is being built by Space Systems Loral (SSL), Palo Alto, California. In order to support the new mission trajectory, SSL redesigned the solar array system from a four-panel array in a straight row on either side of the spacecraft to a more powerful five-panel x-shaped design, commonly used for missions requiring more capability. Much like a sports car, by combining a relatively small spacecraft body with a very high-power solar array design, the Psyche spacecraft will speed to its destination at a faster pace than is typical for a larger spacecraft.

"By increasing the size of the solar arrays, the spacecraft will have the power it needs to support the higher velocity requirements of the updated mission," said SSL Psyche Program Manager Steve Scott.

The Psyche Mission

Psyche, an asteroid orbiting the Sun between Mars and Jupiter, is made almost entirely of nickel-iron metal. As such, it offers a unique look into the violent collisions that created Earth and the terrestrial planets.

The Psyche Mission was selected for flight earlier this year under NASA's Discovery Program, a series of lower-cost, highly focused robotic space missions that are exploring the solar system.

The scientific goals of the Psyche mission are to understand the building blocks of planet formation and explore firsthand a wholly new and unexplored type of world. The mission team seeks to determine whether Psyche is the core of an early planet, how old it is, whether it formed in similar ways to Earth's core, and what its surface is like. The spacecraft's instrument payload will include magnetometers, multispectral imagers, and a gamma ray and neutron spectrometer.

Source: NASA.Gov

Tuesday, May 23, 2017

Image of the Day: A New Look at America's Next Mars Rover...

An artist's concept of NASA's Mars 2020 rover studying the surface of the Red Planet.
NASA / JPL - Caltech

NASA’s Mars 2020 Rover Artist’s Concept (News Release)

This artist's concept depicts NASA's Mars 2020 rover on the surface of Mars.

The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself.

The Mars 2020 rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside on the surface of Mars. A future mission could potentially return these samples to Earth.

Mars 2020 is targeted for launch in July/August 2020, aboard an Atlas V 541 rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida.

NASA's Jet Propulsion Laboratory will build and manage operations of the Mars 2020 rover for the NASA Science Mission Directorate at the agency's headquarters in Washington.

Source: NASA.Gov

Saturday, May 20, 2017

Photos of the Day #4: Explore JPL...

The cruise stage for NASA's Mars 2020 mission on display at the Jet Propulsion Laboratory's (JPL) Spacecraft Assembly Facility...on May 20, 2017.

Earlier today, I drove down to the Jet Propulsion Laboratory (JPL) near Pasadena, California, to attend Explore JPL...formerly known as the JPL Open House. I haven't been to this NASA center since December of 2014 (when I attended the NASA Social for Orion's first mission on Exploration Flight Test 1), and it was cool to see what JPL is working on these days. That would be the Mars 2020 project! While the rover for this mission won't begin construction for another couple of months, engineers inside the Spacecraft Assembly Facility (SAF) have already begun construction on the heat shield (which was transported to another facility for testing when I visited the SAF) and cruise stage (above) for Mars 2020. Assuming that I'll still be available on the weekdays to do this in the future, I'll be planning to sign up for JPL tours over the next 2-3 years to see the progress being made on assembling the Curiosity Mars rover's twin sibling.

Attending the Explore JPL event near Pasadena, California...on May 20, 2017.

I was lucky to secure a ticket for Explore JPL two months ago...since you now need a pass to attend this event due to the Open House getting so popular over the last few years (one culprit for this being that 2015 Matt Damon movie The Martian...which prominently featured JPL, or at least a futuristic version of it) that it couldn't handle the growing number of attendees who showed up to Pasadena. But that's obviously a great thing! JPL will definitely be the place to be at if it's chosen as the manufacturer for the Europa Clipper next decade. The laboratory did, after all, build the Voyager 1 and 2 probes, as well as the Galileo spacecraft that studied Jupiter from 1995 to 2003, and the Cassini orbiter which will end its mission at Saturn this September. So basically, JPL is the site where you can see actual spacecraft destined for the outer planets and the surface of Mars. (Along with Curiosity and Mars 2020, the lab also constructed the Sojourner, Spirit and Opportunity rovers.) That is all.

Inside the Space Flight Operations Facility at JPL...on May 20, 2017.

A full-size model of NASA's InSight Mars lander (set to launch in May of next year) at JPL...on May 20, 2017.

A test version of the Curiosity and Mars 2020 rovers, dubbed Scarecrow, on display at JPL...on May 20, 2017.

A full-size model of the Curiosity Mars rover at JPL...on May 20, 2017.

Full-size models of the Mars Exploration Rover and Sojourner rover (near the right side of this photo) at JPL...on May 20, 2017.

The cruise stage for the Mars 2020 mission on display (along with the work stand for the spacecraft's heat shield, which was at another facility for testing) at JPL...on May 20, 2017.

Tuesday, May 16, 2017

Photos of the Day #3: Meeting Amy Farrah Fowler...

At The Grove's Barnes & Noble bookstore in Los Angeles to attend a discussion and signing by actress/neuroscientist Mayim Bialik...on May 16, 2017.

Almost one week after I met Beth Behrs of the TV sitcom 2 Broke Girls (which was unfortunately cancelled by CBS two days after her book signing), I went back to Barnes & Noble at The Grove a few hours ago to meet another actress on a CBS comedy: Mayim Bialik...who plays Sheldon Cooper's girlfriend Amy Farrah Fowler on the hit series The Big Bang Theory (TBBT). Bialik promoted her new publication Girling Up tonight—going into detail about what she wanted to write about that would inspire young female readers, and mentioning how awesome it is to play a neuroscientist on TV (that would be Amy Fowler, in case you don't watch TBBT) since she's also an actual neuroscientist in real life!

Mayim Bialik discusses her new publication GIRLING UP at The Grove's Barnes & Noble bookstore in Los Angeles...on May 16, 2017.

Bialik's book discussion and Q&A was moderated by comedian Iliza Shlesinger...the 2008 winner of NBC'S Last Comic Standing and the creator of Truth & Iliza (obviously). It was awesome meeting Bialik! (Would've been cool to meet Shlesinger as well! She immediately left the table and exited once the discussion ended... I obviously stayed to get in line for Bialik's autograph signing instead.) Unsurprisingly, when I went up to Mayim's table to finally meet her, I mentioned the shocking last scene between Amy and Sheldon in Big Bang's Season 10 finale on May 11. Did Amy say yes? We'll hopefully find out in the Season 11 premiere this September... Or not. Have a good night.

Comedian Iliza Shlesinger moderates the discussion and Q&A for Mayim Bialik's new publication GIRLING UP...at The Grove's Barnes & Noble bookstore in Los Angeles on May 16, 2017.

Mayim Bialik discusses her new publication GIRLING UP at The Grove's Barnes & Noble bookstore in Los Angeles...on May 16, 2017.

Posing with Mayim Bialik at The Grove's Barnes & Noble bookstore in Los Angeles...on May 16, 2017.

My autographed copy of Mayim Bialik's book GIRLING UP.

Thursday, May 11, 2017

Photos of the Day #2: The Wilshire Grand Center Is Lit Up for the (2024) Olympics...

The rooftop sail of the Wilshire Grand Center is lit up in red, orange and yellow to support Los Angeles' bid for the 2024 Summer Olympic Games...on May 10, 2017.

As I was heading home after attending the book signing by Beth Behrs yesterday, I stopped by downtown Los Angeles to take photos of the Wilshire Grand Center...whose rooftop 'sail' was lit up in red, orange and yellow. Why was it lit up in red, orange and yellow, you ask? Because the LA24 Exploratory Committee wanted to impress the International Olympic Committee (IOC) while it was in SoCal this week to gouge if L.A. will be handed the Summer Games of 2024...as opposed to Paris, L.A.'s only rival in this bid. The IOC will choose the winner sometime this September. Here's hoping that the colorful scheme atop the tallest building west of the Mississippi River will bring the Games of the 33rd Olympiad to the City of Angels seven years from now. Us Angelenos can bitch about the major freeway congestion and overcrowded venues that this event will most definitely bring later.

The rooftop sail of the Wilshire Grand Center is lit up in red, orange and yellow to support Los Angeles' bid for the 2024 Summer Olympic Games...on May 10, 2017.

And in case you're wondering: No, the Wilshire Grand Center hasn't opened to the public yet. That is all.

The rooftop sail of the Wilshire Grand Center is lit up in red, orange and yellow to support Los Angeles' bid for the 2024 Summer Olympic Games...on May 10, 2017.

The rooftop sail of the Wilshire Grand Center is lit up in red, orange and yellow to support Los Angeles' bid for the 2024 Summer Olympic Games...on May 10, 2017.

Wednesday, May 10, 2017

Photos of the Day: Meeting One of the 2 Broke Girls Tonight...

At The Grove's Barnes & Noble bookstore in Los Angeles to attend a discussion and signing by actress Beth Behrs...on May 10, 2017.

Just thought I'd share these pics that I took at the book signing for Beth Behrs, who plays Caroline Channing on the CBS sitcom 2 Broke Girls, at The Grove in Los Angeles tonight. Behrs was very nice in person...going into detail about what motivated her to write The Total ME‑Tox, and how she employed the routines and recipes in her book when she wasn't on set at Warner Bros. Studio filming a 2 Broke Girls episode. Oh, and she's left-handed too—just like me! Very cool! Though we'll ignore the fact that she's a highly-paid celebrity who's now happily engaged to another dude. Anyways, I'm wondering if Kat Dennings (who plays Caroline's BFF Max Black on 2 Broke Girls) will ever write her own book as well...and of course, promote it at Barnes & Noble at The Grove like Behrs did a few hours ago. We'll see.

Beth Behrs poses with her new publication THE TOTAL ME-TOX at The Grove's Barnes & Noble bookstore in Los Angeles...on May 10, 2017.

I'll be heading back to The Grove next Tuesday to meet an actress on another CBS sitcom that I watch...and it happens to be my favorite show on TV right now! Stay tuned.

Beth Behrs discusses her new publication THE TOTAL ME-TOX at The Grove's Barnes & Noble bookstore in Los Angeles...on May 10, 2017.

Beth Behrs is left-handed...like me!

Posing with Beth Behrs at The Grove's Barnes & Noble bookstore in Los Angeles...on May 10, 2017.

My autographed copy of Beth Behrs' book THE TOTAL ME-TOX.

Sunday, May 07, 2017

Welcome Home, OTV-4!

Technicians inspect the X-37B Orbital Test Vehicle after it landed at NASA's Kennedy Space Center in Florida following a 718-day mission in space...on May 7, 2017.
U.S. Air Force

X-37B Orbital Test Vehicle-4 Lands at Kennedy Space Center (Press Release)

WASHINGTON (AFNS) -- The X-37B Orbital Test Vehicle mission 4 (OTV-4), the Air Force's unmanned, reusable space plane, landed at NASA’s Kennedy Space Center Shuttle Landing Facility May 7, 2017.

“Today marks an incredibly exciting day for the 45th Space Wing as we continue to break barriers,” said Brig. Gen. Wayne Monteith, the 45th SW commander. “Our team has been preparing for this event for several years, and I am extremely proud to see our hard work and dedication culminate in today’s safe and successful landing of the X-37B.”

The OTV-4 conducted on-orbit experiments for 718 days during its mission, extending the total number of days spent on-orbit for the OTV program to 2,085 days.

"The landing of OTV-4 marks another success for the X-37B program and the nation," said Lt. Col. Ron Fehlen, X-37B program manager. "This mission once again set an on-orbit endurance record and marks the vehicle's first landing in the state of Florida. We are incredibly pleased with the performance of the space vehicle and are excited about the data gathered to support the scientific and space communities. We are extremely proud of the dedication and hard work by the entire team."

The X-37B is the newest and most advanced re-entry spacecraft. Managed by the Air Force Rapid Capabilities Office, the X-37B program performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies.

"The hard work of the X-37B OTV team and the 45th Space Wing successfully demonstrated the flexibility and resolve necessary to continue the nation's advancement in space," said Randy Walden, the director of the Air Force Rapid Capabilities Office. "The ability to land, refurbish, and launch from the same location further enhances the OTV's ability to rapidly integrate and qualify new space technologies."

The Air Force is preparing to launch the fifth X-37B mission from Cape Canaveral Air Force Station, Florida, later in 2017.

Source: PressReleasePoint

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Technicians inspect the X-37B Orbital Test Vehicle after it landed at NASA's Kennedy Space Center in Florida following a 718-day mission in space...on May 7, 2017.
U.S. Air Force

Thursday, May 04, 2017

Dear Republicans: FUCK YOU...

That's all I have to say. Just...fuck you. I hope House Speaker Ryan and his Republican fucks have karma bite—no, sodomize—them in the asses for passing this fuckin' piece of shit legislation. Medical coverage will plummet, and cancer treatment costs are going to spike because the GOP is a cancer to America. And in case you're wondering why I wish the Republican Party was exterminated at this particular moment, I have a personal reason why I hope Paul Ryan and his conservative band of cocksuckers pay the price for approving a health plan that, since the Congressional Budget Office didn't have a chance to review this new version of the American Health Care Act, will still pose a threat to 24 million (maybe more) Americans.

Once again, FUCK YOU, REPUBLICANS.

House-speaking cocksucker Paul Ryan was integral to getting that abomination known as the American Health Care Act passed.

Monday, May 01, 2017

Grand Finale Update: Cassini's First Dive Was Relatively Dust-Free...

An artist's concept of NASA's Cassini spacecraft approaching the inner gap between Saturn and its rings...as Cassini begins the 'Grand Finale' of its 13-year-long mission at the ringed planet.
NASA / JPL -Caltech

Cassini Finds 'The Big Empty' Close to Saturn (Press Release)

As NASA's Cassini spacecraft prepares to shoot the narrow gap between Saturn and its rings for the second time in its Grand Finale, Cassini engineers are delighted, while ring scientists are puzzled, that the region appears to be relatively dust-free. This assessment is based on data Cassini collected during its first dive through the region on April 26.

With this information in hand, the Cassini team will now move forward with its preferred plan of science observations.

"The region between the rings and Saturn is 'the big empty,' apparently," said Cassini Project Manager Earl Maize of NASA's Jet Propulsion Laboratory in Pasadena, California. "Cassini will stay the course, while the scientists work on the mystery of why the dust level is much lower than expected."

A dustier environment in the gap might have meant the spacecraft's saucer-shaped main antenna would be needed as a shield during most future dives through the ring plane. This would have forced changes to how and when Cassini's instruments would be able to make observations. Fortunately, it appears that the "plan B" option is no longer needed. (There are 21 dives remaining. Four of them pass through the innermost fringes of Saturn's rings, necessitating that the antenna be used as a shield on those orbits.)

Based on images from Cassini, models of the ring particle environment in the approximately 1,200-mile-wide (2,000-kilometer-wide) region between Saturn and its rings suggested the area would not have large particles that would pose a danger to the spacecraft.

But because no spacecraft had ever passed through the region before, Cassini engineers oriented the spacecraft so that its 13-foot-wide (4-meter-wide) antenna pointed in the direction of oncoming ring particles, shielding its delicate instruments as a protective measure during its April 26 dive.

Cassini's Radio and Plasma Wave Science (RPWS) instrument was one of two science instruments with sensors that poke out from the protective shield of the antenna (the other being Cassini's magnetometer). RPWS detected the hits of hundreds of ring particles per second when it crossed the ring plane just outside of Saturn's main rings, but only detected a few pings on April 26.

When RPWS data are converted to an audio format, dust particles hitting the instrument's antennas sound like pops and cracks, covering up the usual whistles and squeaks of waves in the charged particle environment that the instrument is designed to detect. The RPWS team expected to hear a lot of pops and cracks on crossing the ring plane inside the gap, but instead, the whistles and squeaks came through surprisingly clearly on April 26.

"It was a bit disorienting -- we weren't hearing what we expected to hear," said William Kurth, RPWS team lead at the University of Iowa, Iowa City. "I've listened to our data from the first dive several times and I can probably count on my hands the number of dust particle impacts I hear."

The team's analysis suggests Cassini only encountered a few particles as it crossed the gap -- none larger than those in smoke (about 1 micron across).

Cassini will next cross through the ring plane Tuesday, May 2, at 12:38 p.m. PDT (3:38 p.m. EDT) in a region very close to where it passed on the previous dive. During this orbit, in advance of the crossing, Cassini's cameras have been looking closely at the rings; in addition, the spacecraft has rotated (or "rolled") faster than engineers have ever allowed it to before, in order to calibrate the magnetometer. As with the first finale dive, Cassini will be out of contact during closest approach to Saturn, and is scheduled to transmit data from this dive on May 3.

More information about Cassini's Grand Finale, including images and video, is available at:

https://saturn.jpl.nasa.gov/grandfinale

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. JPL designed, developed and assembled the Cassini orbiter.

Source: Jet Propulsion Laboratory

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