"Кассини" !

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 4 мин. назад

Nominal. Such a beautiful word. Data are flowing back to Earth, over a ~billion miles, a trip that takes 78 minutes. https://saturn.jpl.nasa.gov/ 

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 1 мин. назад

The gap between Saturn and its rings is no longer unexplored space – and we're going back 21 times. #GrandFinale! https://go.nasa.gov/1Up1oba

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 2 ч. назад

Our closest look ever at #Saturn's atmosphere and giant hurricane. #GrandFinale! https://go.nasa.gov/29E6ijP 

[sol]

города, города....

[SashaBad]

Скорее грозы, молнии...

[tnt22]

https://www.nasa.gov/feature/jpl/nasa-spacecraft-dives-between-saturn-and-its-rings

April 27, 2017

NASA Spacecraft Dives Between Saturn and Its Rings

Спойлер

 NASA's Cassini spacecraft is shown heading toward the gap between Saturn and its rings in this artist's rendering.
Credits: NASA/JPL-Caltech
 

This unprocessed image shows features in Saturn's atmosphere fr om closer than ever before. The view was captured by NASA's Cassini spacecraft during its first Grand Finale dive past the planet on April 26, 2017.
Credits: NASA/JPL-Caltech/Space Science Institute
 

This unprocessed image shows features in Saturn's atmosphere fr om closer than ever before. The view was captured by NASA's Cassini spacecraft during its first Grand Finale dive past the planet on April 26, 2017.
Credits: NASA/JPL-Caltech/Space Science Institute


This unprocessed image shows features in Saturn's atmosphere fr om closer than ever before. The view was captured by NASA's Cassini spacecraft during its first Grand Finale dive past the planet on April 26, 2017.
Credits: NASA/JPL-Caltech/Space Science Institute

[свернуть]

NASA's Cassini spacecraft is back in contact with Earth after its successful first-ever dive through the narrow gap between the planet Saturn and its rings on April 26, 2017. The spacecraft is in the process of beaming back science and engineering data collected during its passage, via NASA's Deep Space Network Goldstone Complex in California's Mojave Desert. The DSN acquired Cassini's signal at 11:56 p.m. PDT on April 26, 2017 (2:56 a.m. EDT on April 27) and data began flowing at 12:01 a.m. PDT (3:01 a.m. EDT) on April 27.

"In the grandest tradition of exploration, NASA's Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating wh ere our curiosity can take us if we dare," said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington.

As it dove through the gap, Cassini came within about 1,900 miles (3,000 kilometers) of Saturn's cloud tops (wh ere the air pressure is 1 bar -- comparable to the atmospheric pressure of Earth at sea level) and within about 200 miles (300 kilometers) of the innermost visible edge of the rings.

Спойлер

While mission managers were confident Cassini would pass through the gap successfully, they took extra precautions with this first dive, as the region had never been explored.

"No spacecraft has ever been this close to Saturn before. We could only rely on predictions, based on our experience with Saturn's other rings, of what we thought this gap between the rings and Saturn would be like," said Cassini Project Manager Earl Maize of NASA's Jet Propulsion Laboratory in Pasadena, California. "I am delighted to report that Cassini shot through the gap just as we planned and has come out the other side in excellent shape."

The gap between the rings and the top of Saturn's atmosphere is about 1,500 miles (2,000 kilometers) wide. The best models for the region suggested that if there were ring particles in the area wh ere Cassini crossed the ring plane, they would be tiny, on the scale of smoke particles. The spacecraft zipped through this region at speeds of about 77,000 mph (124,000 kph) relative to the planet, so small particles hitting a sensitive area could potentially have disabled the spacecraft.

As a protective measure, the spacecraft used its large, dish-shaped high-gain antenna (13 feet or 4 meters across) as a shield, orienting it in the direction of oncoming ring particles. This meant that the spacecraft was out of contact with Earth during the ring-plane crossing, which took place at 2 a.m. PDT (5 a.m. EDT) on April 26. Cassini was programmed to collect science data while close to the planet and turn toward Earth to make contact about 20 hours after the crossing.

Cassini's next dive through the gap is scheduled for May 2.

Launched in 1997, Cassini arrived at Saturn in 2004. Following its last close flyby of the large moon Titan on April 21 PDT (April 22 EDT), Cassini began what mission planners are calling its "Grand Finale." During this final chapter, Cassini loops Saturn approximately once per week, making a total of 22 dives between the rings and the planet. Data from this first dive will help engineers understand if and how they will need to protect the spacecraft on its future ring-plane crossings. The spacecraft is on a trajectory that will eventually plunge into Saturn's atmosphere -- and end Cassini's mission -- on Sept. 15, 2017.

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

 

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

https://saturn.jpl.nasa.gov/mission/grand-finale/why-cassini-matters/

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

More information about Cassini is at:

 

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

Preston Dyches
 Jet Propulsion Laboratory, Pasadena, Calif.
 818-354-7013
preston.dyches@jpl.nasa.gov

Dwayne Brown/Laurie Cantillo
 NASA Headquarters, Washington
 202-358-1726 / 202-358-1077
Dwayne.c.brown@nasa.gov / Laura.l.cantillo@nasa.gov

2017-126

[свернуть]

Last Updated: April 27, 2017
Editor: Tony Greicius

[tnt22]

Jason Major‏ @JPMajor 6 ч. назад

Animation of images from @CassiniSaturn's close pass over #Saturn on April 26

[nsn]

SashaBad пишет:
Скорее грозы, молнии...

Из анимации видно, что это не вспышки молний. Похоже на облака над более плотными слоями.

[tnt22]

Jonathan McDowell‏Подлинная учетная запись @planet4589 1 ч. назад

An alternative version of my Saturn close approaches pic, showing ring brightness as a proxy for density. Thanks @lukedones & M Hedman

[tnt22]

Анимация 1-го пролёта между Сатурном и кольцами

NASA‏Подлинная учетная запись @NASA 17 мин. назад

Our @CassiniSaturn spacecraft just made the 1st of 22 daring dives btwn Saturn & its rings! More on its #GrandFinale http://go.nasa.gov/2oSCp4N 

[tnt22]

272-я орбита Cassini

Orbit 272 - April 29 - May 6[TH]Event[/TH][TH]Date[/TH][TH]Spacecraft Time (UTC)[/TH][TH]Local Time (PDT)[/TH][TH]Notes[/TH]

Apoapse	Apr 29	2:22 p.m.	7:22 a.m.
Ring Crossing #2	May 2	7:38 p.m.	12:38 p.m.
Downlink	May 3	2:13 p.m.	7:13 a.m.	Estimated Earth Received Time (ERT) is 8:30 a.m. on May 3.

[/li]
• During this orbit, Cassini rolls to calibrate its magnetometer (MAG) for the high-intensity magnetic field observations to be performed when the spacecraft is nearest Saturn. This is the first time MAG has made this sort of observation.
• Cassini's imaging cameras, the Imaging Science Subsystem (ISS), takes advantage of the last opportunity to observe Saturn's rings at extremely high phase angles while the Sun is hidden behind Saturn, allowing the instrument to survey faint ringlets in the main rings, many of which are difficult to observe outside of this geometry. The ISS also collects images to produce a movie to monitor various structures in Saturn's D ring.
• The spacecraft's Composite Infrared Spectrometer (CIRS) observes Saturn's moon Rhea in infrared to narrow down the composition and structure of the moon's surface material.
• During this orbit, Cassini gets within 1,820 miles (2,930 kilometers) of Saturn's 1-bar level. Cassini also passes within 2,980 miles (4,780 kilometers) of the inner edge of Saturn's D ring.
  

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 12 ч. назад

We're at apoapse right now – the farthest from Saturn we'll get in our current orbit. #SaturnSaturday https://go.nasa.gov/2qcf2Vx 

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 12 ч. назад

In our current orbit, we'll roll to calibrate our magnetometer for high-intensity magnetic field scans, another first. #SaturnSaturday

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 4 ч. назад

Coming soon: We'll take a close look at #Saturn's moon Rhea in infrared to analyze composition and structure of the moon. #SaturnSaturday

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 2 мин. назад

Our next ring crossing is May 2 and we'll get our last look at Saturn's rings at a high-phase angle while the sun is hidden by the planet.

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 8 ч. назад

These sounds represent data collected between Saturn & its rings. It's quieter than expected. What that could mean: https://go.nasa.gov/2oRbZFv

https://saturn.jpl.nasa.gov/news/3034/cassini-finds-the-big-empty-close-to-saturn/

May 1, 2017

Cassini Finds 'The Big Empty' Close to Saturn

Спойлер

Cassini Project Manager Earl Maize waits for Cassini's signal with the spacecraft's operations team in mission control at JPL on April 26, 2017. Credit: NASA/JPL-Caltech  › Full Image 

[свернуть]

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.

Спойлер

"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 fr om 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.

This video represents data collected by the Radio and Plasma Wave Science instrument on NASA's Cassini spacecraft, as it crossed the plane of Saturn's rings on Dec. 18, 2016. The instrument is able to record ring particles striking the spacecraft in its data.

This video represents data collected by the Radio and Plasma Wave Science instrument on NASA's Cassini spacecraft, as it crossed through the gap between Saturn and its rings on April 26, 2017, during the first dive of the mission's Grand Finale.

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 wh ere 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.

More information about Cassini:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

Preston Dyches
 Jet Propulsion Laboratory, Pasadena, Calif.
 818-394-7013
 preston.dyches@jpl.nasa.gov

[свернуть]

Written by Jia-Rui Cook and Preston Dyches

[Сергио]

X пишет:
Cassini приносит учёным пять новых загадок Сатурна

5 июля 2004

Первые дни работы космического корабля Cassini в системе Сатурна уже принесли драматическое расширение наших знаний об этой планете. И многие открытия если не поставили учёных в тупик, то привели в некоторое замешательство.

...

На краю колец аппарат обнаружил много атомарного кислорода, который распределён неравномерно, а с одной стороны — интенсивно убегает в космос — что заставило учёных предположить недавнее (буквально в момент прибытия Cassini) столкновение с кольцами некоего объекта.

Продолжал ли убегать кислород поледущие 13 лет?

В плоскости колец также обнаружено большое количество пыли, частицы которой сопоставимы по размеру с частицами сигаретного дыма.
...
http://www.membrana.ru/lenta/?3331

"сигарета мелькает во тьме" (с)

[zandr]

https://ria.ru/science/20170502/1493467223.html

"Кассини" неожиданно не нашел пыли в "дырке" между кольцами и Сатурном
© NASA/JPLКассини во время Финала Оперы
МОСКВА, 2 мая – РИА Новости. Зонд "Кассини" неожиданным образом не нашел никаких следов пыли в промежутке между кольцами и атмосферой Сатурна, через который он пролетел в первый раз неделю назад, в конце апреля этого года, сообщает НАСА.
"Похоже, что регион между кольцами и планетой является "большой пустотой". "Кассини" продолжит двигаться по текущему курсу, а мы начинаем думать над тем, почему число частиц пыли в промежутке гораздо меньше, чем мы ожидали", — заявил Эрл Мейз (Earl Maize), руководитель миссии "Кассини" в НАСА.
Недавно "Кассини" официально начал заключительную фазу в своей жизни, в последний раз встретившись с Титаном 22 апреля этого года. Сближение с этим спутником Сатурна помогло зонду поменять траекторию полета и выйти на курс столкновения с планетой-гигантом, в атмосфере которой он сгорит в середине сентября этого года, совершив 22 пролета через промежуток между кольцами и их "властелином".
В прошлый вторник "Кассини" совершил первый подобный пируэт, максимально тесно сблизившись с Сатурном и получив массу новых научных данных по устройству недр и атмосферы планеты-гиганта. Для дополнительной защиты зонда НАСА развернуло главную антенну "Кассини" таким образом, что она стала своеобразным "щитом", защищающим космический аппарат от ударов пылинок и микроастероидов.
Как рассказывает Мейз, подобные меры предосторожности оказались излишними – детекторы пыли "Кассини" фактически не зафиксировали пролета через промежуток между кольцами и планетой. По словам ученых, пыли в этой части "владений" Сатурна не больше, чем в других регионах открытого космического пространства в его ближайших окрестностях.
Как отмечает Уильям Курт, руководитель команды ученых, работающих с детектором пыли RPWS на борту "Кассини", он и его помощники несколько раз прослушали данные с "счетчика" пылевых частиц для того, чтобы убедиться, что они не ошиблись и что пыли в "щели" между кольцами и планетой действительно нет. По его словам, число частиц пыли, ударивших по "Кассини", можно в буквальном смысле пересчитать по пальцам руки.
Подобное неожиданное открытие заметно облегчает работу для пилотов и инженеров миссии – теперь им не придется гадать о том, стоит ли рисковать более хрупкими инструментами зонда при пролете через кольца, и поворачивать антенну для защиты "Кассини" от разрушения.
В следующий раз "Кассини" пролетит через этот промежуток сегодня ночью, в 22 часа 38 минут по Москве, и на этот раз он попытается сфотографировать кольца "в профиль", а также проведет точнейшие замеры силы магнитного поля планеты и соберет другие данные. Во время пролета через эту зону зонд будет лишен связи с Землей, из-за чего ученые узнают о итогах этого "нырка" только после его успешного завершения в среду.

© NASA/JPL-Caltech/University of Iowa
Данные детектора пыли с "Кассини", не нашедшего пыли в промежутке между кольцами и планетой

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 24 мин. назад

An unprocessed image shows our view of #Saturn in our #GrandFInale orbits. https://saturn.jpl.nasa.gov/ 

[tnt22]

CassiniSaturn‏Подлинная учетная запись @CassiniSaturn 21 мин. назад

We're making our 2nd dive through #Saturn's ring gap RIGHT NOW! #GrandFinale https://go.nasa.gov/2qcf2Vx