А теперь к Плутону (АМС New Horizons / Новые горизонты)

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2011 HM₁₀₂: A new companion for Neptune

http://www.planetary.org/blogs/guest-blogs/2013/0430-2011hm102-new-neptune-companion.html

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The PI's Perspective: Encounter Planning Accelerates
 
May 16, 2013

The New Horizons team studied numerous alternate flybys, called SHBOTs, before recommending to NASA a pair of backups to protect New Horizons fr om possible impact hazards in the Pluto system.
 
All exploration comes with both rewards and risks.
Back in 2005 and 2006, when Pluto's second and third moons (Nix and Hydra) were discovered, searches by astronomers for still more moons didn't reveal any. So the accidental discovery of Pluto's fourth moon by the Hubble Space Telescope in mid-2011 (during a search for Plutonian rings) raised the possibility that the hazards in the Pluto system might be greater than previously anticipated. Those concerns were amplified when Hubble discovered a fifth moon in 2012. As a result of those discoveries, the New Horizons science and operations teams began to more carefully scrutinize the true level of hazards to our spacecraft at closest approach and devise mitigation strategies to make sure the encounter with Pluto would be successful.
We've now largely completed that work and presented the results to both an independent, NASA-appointed technical review team, led by the Jet Propulsion Laboratory's Keyur Patel, and then to senior executives at NASA Headquarters. Both groups have concurred with our findings, which I can summarize as follows:
 

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• New Horizons benefits fr om its approach trajectory because that trajectory is steeply inclined to Pluto's satellite plane and associated debris hazards that models show should lie close to the satellite plane. As a result, most of the risk New Horizons faces occurs only at closest approach, when the spacecraft is very near the satellite plane.
  

The New Horizons trajectory (red line) is steeply inclined to Pluto's satellite plane, thereby restricting satellite debris hazards – which lie near the satellite plane – to the short time near closest approach.
 

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• The Pluto system appears to be far safer than early fears and initial calculations indicated when the new moons began popping up. In fact, the best current models predict a 0.3% (1-in-300) chance of a mission-ending impact near closest approach on the nominal trajectory. Much of the reason for this lowered risk assessment is that more sophisticated dust-impact models revealed a decrease (by about a factor of 100) in lethal impact probability for trajectories that fly into the region wh ere New Horizons is aimed now – a region wh ere the gravitational effects of Pluto's largest moon Charon clear debris. Another important factor is that when we tested spacecraft components against high-velocity impacts using gun ranges in New Mexico and Ohio, we found the spacecraft shielding is considerably "harder"– that is, more resistant to impacts – than preflight estimates indicated.
  

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• The baselined New Horizons closest-approach aim point is one of the safest possible aim points – if not the safest aim point – in the Pluto system. This is because we're headed to a closest approach in the region that Pluto's Texas-sized moon Charon efficiently clears of debris. In fact, Charon offers such a good hazard-removal service that even if a recent impact onto a small moon created debris near Charon's orbit just months before encounter, Charon would clear almost all of it by the time the spacecraft arrives.
  

Thanks to these three findings, we're much more confident that unless something new and unexpected comes up between now and encounter, our current plan, which has been optimized to maximize the encounter science return, is to the best level of current knowledge, safe.
But to be still more prudent, we're also implementing plans during the final weeks of approach in summer 2015 for New Horizons itself to search for hazards that we can't see from Hubble or Earth-based telescopes. And we've also added "fail safe" data downlinks just two days and one day before the encounter to send home the best images and spectra stored on the spacecraft's recorders, just in case our current estimates are wrong and we do lose New Horizons at closest approach. It's always better to plan this way, just as the Apollo astronauts collected contingency samples right after stepping onto the moon in case they had to make a hurried getaway before their moonwalks could be completed.
And – just as every space shuttle mission included (but never used) plans to land after just one orbit of Earth if the spacecraft wasn't healthy enough to continue – we are also prudently planning two alternate encounter sequences that we can upload to New Horizons as late as 10 days before closest approach, in the unlikely event that our hazard observations on final approach raise new cautions.

http://pluto.jhuapl.edu/overview/piPerspective.php?page=piPerspective_05_16_2013

The PI's Perspective: Encounter Planning Accelerates

Safe Havens
These backup encounter sequence plans are called SHBOTs, an acronym for Safe Haven By Other Trajectory.
Our first SHBOT is called GIS, for Generic Inner SHBOT. It continues on the nominal trajectory and aim point, but for three hours near closest approach, we repoint the spacecraft so its dish antenna can shield it from impacts. This pointing attitude, called Antenna to Ram (or ATR), would cost us some science because we won't be as free to point the science instruments toward Pluto system targets during those three hours. But tests and modeling show this provides a factor of three to four times increase in success probability, and reduces the estimated loss of mission probability to about 1 in 1,000.

If necessary, the high-gain ("dish") antenna on New Horizons can be used to shield most of the spacecraft from dust particle impacts during the Pluto encounter.
Our second SHBOT is called DIS, for Deep Inner SHBOT. DIS also uses the ATR attitude. It also directs the spacecraft toward a much closer encounter with Pluto – just inside 3,000 kilometers from Pluto's surface, compared to the nominal encounter close approach of about 12,500 kilometers from the surface. Why go closer, not farther, to avoid hazards? Because if we go close enough, we can benefit from the fortuitous "drag clearing" of debris particles from Pluto's extended upper atmosphere! DIS has more severe science impacts than does GIS, but there is a strong consensus among the team that it's both the best choice if late-breaking news tells us the nominal trajectory is unexpectedly riskier than we're comfortable with, and losing some science to execute Deep Inner SHBOT is far better than losing the mission to a lethal impact.
What I've briefly summarized here resulted from thousands of hours of work by many people on New Horizons and in the scientific community. They've been carefully scrutinized by the independent technical panel NASA set up at our request to peer-review the hazards analysis and mitigation plans we've worked on since late 2011, and approved by NASA Headquarters.
We're excited to have these plans on the books and to begin testing both SHBOTs before the encounter begins so that they are ready to use if needed. When we launched we never imagined we'd be planning three separate encounters with Pluto, but that's what we're doing!

http://pluto.jhuapl.edu/overview/piPerspective.php?page=piPerspective_05_16_2013_2

The PI's Perspective: Encounter Planning Accelerates
 
Waking Up New Horizons for Summer 2013!
 
Before I close this column out, I also want to upd ate you on mission status and other project news.
Currently, New Horizons itself is about 2.6 billion miles from the Sun, and only about 600 million miles from Pluto. Arrival at Pluto is just under 700 days away – still a long time, but much less than the nearly 2,700 days we've been traveling since launch!
New Horizons is healthy and on course, with all systems and science sensors working. On May 21, we'll wake the spacecraft from its most recent, 100-plus day hibernation to begin a busy annual checkout, which will include thorough checks of all backup systems, instrument payload calibrations, and an update of our fault protection software with the next-to-last planned se t of enhancements before we start the Pluto encounter in January 2015 – just over 19 months from now.
This summer's wakeup will also include our most comprehensive on-the-spacecraft close-encounter rehearsal. For nine days, beginning July 5, New Horizons will execute all the activities of its final week on approach to Pluto, closest approach day, and then some of the post-encounter timeline as well. This rehearsal follows up on our successful encounter-day practice from last summer.
After the nine-day rehearsal, we'll downlink a large amount of data through NASA's Deep Space Network  to evaluate how the rehearsal went, collect more cruise science data, conduct more spacecraft navigation tracking, and then put New Horizons back into hibernation on August 21 for another 4½ months, while the team works on SHBOT encounter sequencing.
Also this summer, we'll be close enough to resolve Pluto from its large moon Charon using our long-focal length telescopic imager called LORRI. The first week of July is also the 35th anniversary of Charon's discovery and – entirely by coincidence – we'll be taking our first images of Charon at the same time of year that the moon was discovered, back in 1978!
One thing we won't be doing this summer is a course correction. As in 2011 and 2012, our spacecraft navigation team has determined from tracking data that we're on course and that there is no need to spend any fuel this way – a good thing!
Our mission team can feel the increased pace of activity as we draw closer and closer to 2015, and many of us are working much longer hours on this project than we did in early- and mid-cruise. To prepare for encounter operations to start in January 2015, we'll add new staff to our science and operations teams. In fact, we've already made one very important addition by bringing in a deputy project manager, Peter Bedini, of the Johns Hopkins Applied Physics Laboratory. Peter was most recently the project manager for APL's MESSENGER Mercury orbiter. New Horizons is privileged to have someone as talented and experienced as Peter on our team. So, welcome Peter to a spacecraft and encounter target that are a lot cooler than Mercury – in fact, about 600 degrees Celsius cooler.
As I close this update, I'll just say thanks to all of you for following our journey across the deep ocean of space, to a new planet, and a truly new frontier. I'll plan another update as we complete this summer's intensive mission operations. In the meantime, be on the lookout for a news notes on our website related to this summer's activities.
Until I write again, I hope you'll keep on exploring – just as we do!
–Alan Stern

http://pluto.jhuapl.edu/overview/piPerspective.php?page=piPerspective_05_16_2013_3

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New Horizons Team Sticking to Original Flight Plan at Pluto
 
June 14, 2013
 
 Unless significant new hazards are found, expect NASA's New Horizons spacecraft to stay on its original course past Pluto and its moons, after mission managers concluded that the danger posed by dust and debris in the Pluto system is less than they once feared.
 
 The New Horizons team recently completed an 18-month study of potential impact hazards – mostly dust created by objects hitting Pluto's small satellites – the spacecraft would face as it speeds some 30,000 miles per hour (more than 48,000 kilometers per hour) past Pluto in July 2015. The team estimated that the probability of a mission-ending dust impact was less than 0.3 percent if the spacecraft followed the current baseline plan, far below some early, more conservative estimates. So, with the concurrence of an independent review panel and NASA, the project team expects to keep New Horizons on this baseline course, which includes a close approach of about 12,500 kilometers (nearly 7,800 miles) fr om the surface of Pluto.
 
 "We found that loss of the New Horizons mission by dust impacting the spacecraft is very unlikely, and we expect to follow the nominal, or baseline, mission timeline that we've been refining over the past few years," says New Horizons Project Scientist Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory. "Still, we'll be ready with two alternative timelines, in the event that the impact risk turns out to be greater than we think."
 
 Those alternate plans (called SHBOTs, short for Safe Haven by Other Trajectories) are being developed should new information – gathered from New Horizons camera observations during the approach to Pluto, for example, or new dust-dynamics analyses – indicate less-than-smooth sailing for New Horizons.
 
 One plan, the Generic Inner SHBOT, is essentially the same as baseline trajectory, but with the spacecraft turned so that its 7-foot dish antenna faces the incoming dust particles; this "Antenna-to-Ram" (or ATR) configuration would protect the spacecraft underneath. The Deep Inner SHBOT also employs ATR protection, but would additionally dip the trajectory to within just 3,000 kilometers (nearly 1,900 miles) of Pluto's surface, wh ere atmospheric drag tends to sweep out lingering dust.

 

Read more about the New Horizons impact-hazard study and SHBOTs

New Horizons managers recently presented their impact-hazard outlook and if-necessary mitigation plans to an independent NASA review panel and to the NASA Science Mission Directorate Program Management Council – receiving endorsements from both.

 New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute, says the mission team is now finalizing plans for the Pluto encounter. In early July, the team will rehearse the most critical nine-day segment of the baseline encounter plan, putting itself and the spacecraft through the paces of the flight toward and just past Pluto and its moons.

 Stern adds that the spacecraft remains on target for a close approach to Pluto in 2015, all subsystems are performing nominally, and "the anticipated science observations will revolutionize our understanding of dwarf planets and the Kuiper belt, and excite a whole new generation of the public to the first reconnaissance of a planet on the very frontier of our solar system."

 

Track New Horizons on its voyage to Pluto and beyond

 Safe passage: With the dust-impact hazard less than once feared, the New Horizons team plans to keep its spacecraft on the baseline trajectory through the Pluto system.

http://pluto.jhuapl.edu/news_center/news/20130614.php

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http://pluto.jhuapl.edu/mission/whereis_nh.php



6 а.е. до Плутона!

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instml пишет:
 http://pluto.jhuapl.edu/mission/whereis_nh.php

[IMG]
 
6 а.е. до Плутона!

Вроде бы вопрос поднимался уже, с какой дистанции снимки станут лучше Хаббла?
 
з.ы. у меня получается разрешение LORRI 1 секунда. У Хаббла 0,1. Значит надо быть в 10 раз ближе. т.е. 3 а.е. В следующем году? Однако, Вика говорит, что снимки станут лучше только за месяц до пролета. Где ошибка?

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Весной 2015....

Планируется, что в июле 2013 АМС New Horizons будет фотографировать Плутон и на этих фотографиях получится разрешить по отдельности Плутон и Харон.

Что касается Хаббла, с помощью хитрых методов его разрешение улучшили.

Смотрим http://www.nasa.gov/mission_pages/hubble/science/pluto-20100204.html :

The Hubble images will remain our sharpest view of Pluto until NASA's New Horizons probe is within six months of its Pluto flyby. The Hubble pictures are proving invaluable for picking out the planet's most interesting-looking hemisphere for the New Horizons spacecraft to swoop over when it flies by Pluto in 2015.

The Hubble images are a few pixels wide. But through a technique called dithering, multiple, slightly offset pictures can be combined through computer-image processing to synthesize a higher-resolution view than could be seen in a single exposure. "This has taken four years and 20 computers operating continuously and simultaneously to accomplish," says Buie, who developed special algorithms to sharpen the Hubble data.

http://solarsystem.nasa.gov/multimedia/display.cfm?Category=Planets&IM_ID=10363

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Sellin пишет:
з.ы. у меня получается разрешение LORRI 1 секунда. У Хаббла 0,1. Значит надо быть в 10 раз ближе. т.е. 3 а.е. В следующем году? Однако, Вика говорит, что снимки станут лучше только за месяц до пролета. Где ошибка?

"... За 90 суток до пролёта Плутона с расстояния около 100 млн км полученные изображения уже будут превосходить по разрешению снимки с "Хаббла". Непосредственно при пролёте камера будет снимать отдельные участки освещённого полушария Плутона с разрешением до 50 м".
Новости космонавтики №3 2006 г., стр. 4

[smokan]

Я тоже помню четко из интервью творцов Новых Горизонтов, то что фотографии с аппарата станут лучше от хабловских уже за три месяца до пролета Плутона

[pkl]

instml пишет:
Весной 2015....

Планируется, что в июле 2013 АМС New Horizons будет фотографировать Плутон и на этих фотографиях получится разрешить по отдельности Плутон и Харон.

Что касается Хаббла, с помощью хитрых методов его разрешение улучшили.

 

На Плутоне в южном полушарии, похоже, крупный кратер. Или депрессия типа Моря Дождей.

[Vasily]

pkl пишет:
На Плутоне в южном полушарии, похоже, крупный кратер. Или депрессия типа Моря Дождей.

Больше похоже на старые тёмные регионы Ганимеда, вроде обл. Галилея.

[pkl]

Ну так это тоже, вроде, ударный бассейн.

[Чебурашка]

По мне так, эти тёмные пятна, аналогичны по своей природе, тёмным и светлым пятнам на поверхности Тритона. Плутон по размерам и температурным условиям очень близок к спутнику Нептуна. И, логично, ожидать от Плутона аналогичного вида поверхности.

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Тритон геологически активен, чего трудно ожидать от Плуто.

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Sellin пишет:
Тритон геологически активен, чего трудно ожидать от Плуто.

Может, его Харон, обращающийся по орбите с малым радиусом приливными силами разогревает...

[Bizonich]

Александр Хороших пишет:
Может, его Харон, обращающийся по орбите с малым радиусом приливными силами разогревает...

Система Плутон-Харон стабилизирована, они всегда повернуты одной стороной друг к другу. Приливные массы всегда находятся в одном положении. Окажут ли они влияние на геологическую активность? Я думаю, что уже нет.

[C-300]

Bizonich пишет:
Система Плутон-Харон стабилизирована, они всегда повернуты одной стороной друг к другу. Приливные массы всегда находятся в одном положении. Окажут ли они влияние на геологическую активность? Я думаю, что уже нет.

Не знал. Спасибо!

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Согласно опубликованным планам, в понедельник 01.07.13 камера LORRI на АМС будет фотографировать Плутон и Харон!

New Horizons will take its first picture of Charon apart from Pluto-- on Monday!

https://twitter.com/NewHorizons2015/status/350463872265756674

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Два новых спутника Плутона получили имена Цербер и Стикс

МОСКВА, 2 июл — РИА Новости. Два новых спутника Плутона, открытые в 2011 и 2012 годах, получили официальные имена — Цербер и Стикс — соответствующее решение принял Международный астрономический союз, говорится в сообщении Института проекта SETI.
Первые три спутника Плутона — Харон, Никта и Гидра — были открыты с 1978 по 2005 год, а в 2011 и 2012 годах космический телескоп "Хаббл" обнаружил два новых спутника, получивших временные обозначения P4 и P5. Размеры спутника P4 — от 13 до 34 километров, P5 — от 15 до 24 километров.

Группа первооткрывателей под руководством Марка Шуолтера (Mark Showalter) из Института проекта SETI обратилась к интернет-сообществу с предложением выбрать названия для спутников. Согласно правилам Международного астрономического союза, они должны получать имена персонажей, связанных с царством мертвых греко-римской мифологии. Поэтому ученые предложили для голосования 12 вариантов: Ахерон, Стикс и Лета (реки в подземном царстве), Алекто (богиня мщения), Цербер, Эреб, Эвридика, Геркулес, Гипнос (бог сна), Обол (монета, которую следует уплатить Харону), Орфей, Персефона.
В голосовании приняло участие почти 500 тысяч человек, которые также предложили около 30 тысяч своих вариантов. В результате, "Цербер" занял второе место, а "Стикс" — третье. Лидером голосования стал "Вулкан".
Это имя предложил Уильям Шетнер, звезда сериала "Звездный путь". Вулкан — это родная планета персонажа сериала мистера Спока и имя бога огня в древнеримской мифологии. Но этот вариант был отвергнут, так как Вулкан не имеет прямого отношения к царству мертвых и так уже была названа планета, по предположениям ученых 19-го века находившаяся между Меркурием и Солнцем, существование которой не подтвердилось.
В неформальном голосовании, которое проводилось в соцсетях после открытия P4, лидером стал Микки, в честь Микки Мауса, кроме того, были предложены имена других диснеевский персонажей, а также героев книг про Гарри Поттера (Дамблдор, Снейп), и Ктулху из произведений Говарда Лавкрафта.

http://ria.ru/science/20130702/947161532.html

[G.K.]

Кто-то там пишет:
В неформальном голосовании, которое проводилось в соцсетях после открытия P4, лидером стал Микки, в честь Микки Мауса, кроме того, были предложены имена других диснеевский персонажей, а также героев книг про Гарри Поттера (Дамблдор, Снейп), и Ктулху из произведений Говарда Лавкрафта.

Мда

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Kerberos and Styx: Welcome to the Pluto System!
 Pluto's Smallest Moons Receive Official Names 
 
July 2, 2013
 
 The names of Pluto's two smallest known moons, previously referred to as "P4" and "P5," have been formally approved by the International Astronomical Uni on (IAU). P4 has been named Kerberos, after the three-headed dog of Greek mythology. P5 has been named Styx, after the mythological river that separates the world of the living from the realm of the dead. They join Pluto's previously known moons Charon, Nix and Hydra. According to IAU rules, Pluto's moons are named for characters associated with the Underworld of Greek and Roman mythology.
Mark Showalter, senior research scientist at the SETI Institute in Mountain View, Calif., led the team of astronomers that discovered Kerberos and Styx. Both were first seen in lengthy exposures of the Pluto system obtained by the Hubble Space Telescope. Kerberos was discovered in 2011 and Styx in 2012. The images were obtained in support of NASA's New Horizons mission, which will fly past Pluto in July 2015.
The names were sel ected based on the results of an unprecedented Internet vote that was held during February 2012. The ballot at plutorocks.seti.org received almost 500,000 votes, including 30,000 write-in suggestions. "I was overwhelmed by the public response to the naming campaign," says Showalter, adding that the website received international attention and half the votes came from outside the U.S.
Kerberos is the Greek form of the name Cerberus, which ranked second in the voting. Styx ranked third. The top vote-getter was "Vulcan," based on a suggestion from actor William Shatner of TV's "Star Trek" fame. Vulcan was the name of the home planet of Star Trek character Mr. Spock. The IAU gave serious consideration to this name, which happens to be shared by the Roman god of volcanoes. However, because the name has already been used in astronomy, and because the Roman god is not closely associated with Pluto, this proposal was rejected. "I am grateful to the IAU for giving such careful consideration to our suggestions," says Showalter.
New Horizons will provide up-close looks at Kerberos, Styx and their companion moons in 2015, when it becomes the first spacecraft to fly through the Pluto system. "The discoveries of Kerberos and Styx add to the mysteries surrounding the formation of the Pluto system," says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute.
During the flyby, the spacecraft will also search for additional moons, which might be too small for the Hubble telescope to detect. Afterward, New Horizons will go on to explore the more distant Kuiper Belt.

 

Watch the Google+ Hangout on the name announcement.

 Hubble Space Telescope image of the Pluto system, taken in July 2012.
 
http://pluto.jhuapl.edu/news_center/news/20130702.php