Solar Probe Plus – Delta IV H/Star-48BV – Canaveral SLC-37B – 12.08.2018 в 07:31 UTC

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NASA Sun & Space‏Подлинная учетная запись @NASASun 48 мин. назад

Right now, #ParkerSolarProbe is more than 26 million miles from Earth! Track its journey through the solar system with updates every hour: http://parkersolarprobe.jhuapl.edu/The-Mission/index.php#Where-Is-PSP ...

https://video.twimg.com/tweet_video/Dn389aNXkAEYv3Y.mp4
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Jonathan McDowell‏Подлинная учетная запись @planet4589 9 мин. назад

Parker Solar Probe now has a heliocentric velocity of 28 km/s as it falls sunward. It is now 11 million km from Venus, and will enter the Venusian gravitational sphere on Tuesday evening as it approaches its first flyby, which will lower its perihelion from 31 to 25 million km

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https://blogs.nasa.gov/parkersolarprobe/2018/10/02/fall-2018-milestones-for-parker-solar-probe/

Fall 2018 Milestones for Parker Solar Probe

Sarah Frazier
Posted Oct 2, 2018 at 10:11 am

We like to call Parker Solar Probe the coolest, hottest, fastest mission under the Sun — and fall 2018 will prove why. Here are a few mission milestones to look forward to over the coming months.

Oct. 3, 2018 (about 4:45 a.m. EDT) — Parker Solar Probe performs its first Venus gravity assist. This maneuver — to be repeated six more times over the lifetime of the mission — will change Parker Solar Probe's trajectory to take the spacecraft closer to the Sun.


An illustration of Parker Solar Probe passing Venus. Credit: NASA/Johns Hopkins APL/Steve Gribben

Oct. 29, 2018 — Parker Solar Probe is expected to come within 27 million miles of the Sun. This is the record currently held by Helios 2, set in 1976.

Oct. 30, 2018 — Parker Solar Probe is expected to surpass a heliocentric speed of 153,454 miles per hour. This is the record for fastest spacecraft measured relative to the Sun, set by Helios 2 in 1976.

These speed and distance estimates could change after Parker Solar Probe performs its Venus gravity assist on Oct. 3.

Oct. 31 – Nov. 11, 2018 — Parker Solar Probe performs its first solar encounter. Throughout this period, the spacecraft will gather valuable science data. It will not be in contact with Earth because of the Sun's interference and the orientation needed to keep the spacecraft's heat shield between it and the Sun. The spacecraft is expected to reach its closest approach on Nov. 6. Like the distance and speed records, this estimate could change after the Venus gravity assist.

December 2018 — Parker Solar Probe will downlink the science data gathered during its first solar encounter.

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Jonathan McDowell‏Подлинная учетная запись @planet4589 20:10 - 2 окт. 2018 г.

The @ParkerSunProbe entered Venus' gravitational sphere at 2035 UTC Oct 2. Venus closest approach in a little under 6 hours; will change Parker's orbit around the Sun, lowering its perihelion

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Jonathan McDowell‏Подлинная учетная запись @planet4589 30 мин. назад

Parker Solar Probe flew 2428 km above the surface of Venus at 0846 UTC Oct 3 and is now climbing out of the Venusian gravity well. It will depart the Venus gravitational sphere at 2056 UTC

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Jonathan McDowell‏Подлинная учетная запись @planet4589 16 мин. назад

Before encounter, Parker was in a 0.208 x 1.014 AU x 5.6 deg solar orbit (31 x 152 million km). After, it will be in a 0.166 x 0.938 AU x 3.4 deg (25 x 140 million km). First perihelion is Nov 6 0329 UTC

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https://blogs.nasa.gov/parkersolarprobe/2018/10/03/parker-solar-probe-successfully-completes-first-venus-flyby/

Parker Solar Probe Successfully Completes First Venus Flyby

Sarah Frazier
Posted Oct 3, 2018 at 11:14 am

On Oct. 3, Parker Solar Probe successfully completed its flyby of Venus at a distance of about 1,500 miles during the first Venus gravity assist of the mission. These gravity assists will help the spacecraft tighten its orbit closer and closer to the Sun over the course of the mission.


The orbit design for the Parker Solar Probe mission. Credit: NASA/Johns Hopkins APL

Detailed data from the flyby will be assessed over the next few days. This data allows the flight operations team to prepare for the remaining six Venus gravity assists which will occur over the course of the seven-year mission.

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https://tass.ru/kosmos/5635407

4 ОКТ, 08:24

NASA: американский зонд успешно выполнил гравитационный маневр у Венеры на пути к Солнцу

Такие маневры помогут аппарату приблизиться к солнечной короне

ВАШИНГТОН, 4 октября. /Корр. ТАСС Дмитрий Кирсанов/. Американская автоматическая станция, предназначенная для исследования Солнца, благополучно выполнила в среду первый гравитационный маневр у Венеры на своем пути к пункту назначения. Об этом сообщило Национальное управление США по аэронавтике и исследованию космического пространства (NASA).

"Зонд имени Паркера успешно выполнил 3 октября пролет у Венеры на расстоянии примерно 1,5 тыс. миль (2,4 тыс. км)", - отметило космическое ведомство. По его свидетельству, речь идет о "первом гравитационном маневре" с использованием силы притяжения Венеры, предназначенном для изменения траектории полета станции. "Эти гравитационные маневры помогут аппарату переходить на орбиту все ближе и ближе к Солнцу по мере реализации миссии", - пояснило NASA. Согласно изложенной им информации, в течение 7-летней миссии станция должна совершить аналогичный маневр еще шесть раз.

Детали миссии

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Планируется, что в ноябре зонд приблизится к Солнцу на расстояние в 6,4 млн км. Это означает, что аппарат будет находиться в пределах короны Солнца, то есть внешних слоев его атмосферы, где температура может достигать 500 тыс. кельвинов и даже нескольких миллионов кельвинов.

По замыслу американских ученых, в период по июнь 2025 года зонд совершит 24 витка по орбите вокруг Солнца, разгоняясь до скорости 724 тыс. км в час. На каждый такой виток у него будет уходить 88 дней.

На борту аппарата стоимостью порядка $1,5 млрд размещено четыре комплекта научных инструментов. При помощи этой аппаратуры специалисты рассчитывают, в частности, осуществить различные измерения солнечной радиации. Наряду с этим зонд должен будет передать фотоснимки, которые станут первыми, сделанными в пределах солнечной короны. Оборудование зонда защищено оболочкой из углепластика толщиной 11,43 см, позволяющей выдержать температуру до примерно 1,4 тыс. градусов Цельсия.

Как признала в июне прошлого года координатор данного проекта NASA Никола Фокс, его удалось реализовать только теперь благодаря появлению новых материалов, использованных в первую очередь при создании термостойкого щита зонда. Станция получила и новые панели солнечных батарей, уточнила Фокс. "Мы наконец прикоснемся к Солнцу", - сказала о курируемом проекте эксперт из Лаборатории прикладной физики Университета Джонса Гопкинса. По ее выражению, зонд поможет ученым понять, "как работает Солнце".

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Значение проекта

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NASA обещает, что миссия произведет революцию в представлении человека о процессах, протекающих на Солнце. Претворение в жизнь намеченных планов позволит внести "фундаментальный вклад" в понимание причин "нагревания солнечной короны", а также возникновения солнечного ветра (потока ионизированных частиц, истекающего из солнечной короны) и "ответить на критически важные вопросы в гелиофизике, которые уже на протяжении нескольких десятилетий имеют высший приоритет", убеждено NASA.

Информация с борта аппарата, по мнению его специалистов, будет иметь огромную ценность и с точки зрения подготовки дальнейших пилотируемых полетов за пределы Земли, поскольку позволит прогнозировать "радиационную обстановку, в которой предстоит работать и жить будущим покорителям космоса".

Зонд назван в честь выдающегося американского астрофизика Юджина Паркера, которому минувшим летом исполнился 91 год. Паркер стал одним из первых в мире специалистов, занимавшихся исследованиями солнечного ветра. С 1967 года он является членом Национальной академии наук США.

Предполагается, что зонд Паркера подлетит в семь раз ближе к Солнцу, чем какой-либо другой из космических аппаратов, ранее отправлявшихся человеком.

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https://www.nasa.gov/feature/goddard/2018/parker-solar-probe-changed-the-game-before-it-even-launched

Oct. 4, 2018

Parker Solar Probe Changed the Game Before it Even Launched

On Oct. 3, 2018, Parker Solar Probe performed the first significant celestial maneuver of its seven-year mission. As the orbits of the spacecraft and Venus converged toward the same point, Parker Solar Probe slipped in front of the planet, allowing Venus' gravity — relatively small by celestial standards — to twist its path and change its speed. This maneuver, called a gravity assist, reduced Parker's speed relative to the Sun by 10 percent — amounting to 7,000 miles per hour — drawing the closest point of its orbit, called perihelion, nearer to the star by 4 million miles.

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Parker Solar Probe completed its first flyby of Venus on Oct. 3, 2018, during a Venus gravity assist, where the spacecraft used the planet's gravity to alter its trajectory and bring it closer to the Sun.
Credits: NASA/JHUAPL
Download Parker Solar Probe multimedia in HD formats fr om NASA Goddard's Scientific Visualization Studio

Performed six more times over the course of the seven-year mission, these gravity assists will eventually bring Parker Solar Probe's closest approach to a record 3.83 million miles from the Sun's surface — about a seventh the distance of the current record-holder, Helios 2, which achieved a pass of 27 million miles from the Sun in 1976. Even before its closest approach, Parker Solar Probe is expected to overtake this record and become the closest human-made object to the Sun in late October 2018.

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A long-held dream

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A solar probe has been on the minds of scientists and engineers for decades, since the late '50s, when a new theory and the first satellite measurements of the Sun's constant outflow of material, called the solar wind, pointed towards previously unsuspected complexity. But if you'd asked anyone before 2007 — well after serious planning for such a mission began — Venus would not have come up as the key to the mission puzzle. For the three-plus decades that various committees and teams worked on different concepts for the solar probe mission, it was widely agreed that the only way to dive into the solar atmosphere required sending the spacecraft to Jupiter first.

"No one believed using Venus gravity assists would be possible, because the gravity assist a planetary body can provide is proportional to the body's mass, and Venus' mass is so much smaller — only 0.3 percent of Jupiter's," said Yanping Guo, mission design and navigation manager for the Parker Solar Probe mission at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland. " You compare the gravity assist Venus can provide to what Jupiter can provide, and you have to do repeated flybys to achieve the same change. Then you're getting a very long mission duration."

Getting close to the Sun is more difficult than one might think. Any spacecraft launched from Earth starts off traveling at our planet's 67,000-mile-per-hour sideways pace, speed that it must counteract before it can get anywhere near the Sun. Gravity assists are one of the most powerful tools in an orbit designer's toolbox to solve this problem: Instead of using expensive, precious fuel to change direction or speed (or both), gravity assists let you harness the natural pull of a planet, with time as the only cost.

https://www.youtube.com/watch?time_continue=1&v=dhDD2KaflSU
(video 2:23)
Though the Sun's mass holds our solar system together, it takes a lot of energy to get close to the Sun, because an object launched from Earth starts out traveling at Earth's 67,000-mile-per-hour speed.
Credits: NASA's Goddard Space Flight Center
Download this video in HD formats from NASA Goddard's Scientific Visualization Studio

Most deep-space missions that use planetary gravity assists use them to gain speed — like OSIRIS-Rex, which used Earth's gravity to rocket towards asteroid Bennu — or to change direction — like Voyager 2, which performed a gravity assist after its final planetary flyby at Neptune to bank toward its moon, Triton.  

The idea for a solar probe gravity assist was a little different. In the original orbit plans, the primary functions of the Jupiter gravity assist were to slow the spacecraft's speed to almost nothing and fling it upwards, out of the nearly-flat plane that contains all of the known planets of the solar system, called the ecliptic plane. This would put the solar probe on a path to get a rare and better-than-ever look at the Sun's polar regions, which are difficult to image, but important scientifically as they produce some of the Sun's high-speed solar wind. Nearly all of our solar observatories have orbited in the ecliptic plane, with the exception of Ulysses, which used a Jupiter gravity assist to achieve polar passes more than 200 million miles from the Sun.

But sending a spacecraft out to Jupiter and bringing it back into the inner solar system is hard. First, no matter how you plan the journey, it's a long mission, with a minimum of nearly half a decade between meaningful events. Most of the time would be spent cruising in deep space.

Second, traveling that far from the Sun means you have to get creative with power. Near Jupiter, the sunlight is about 25 times dimmer than what we experience at Earth, so the only options are huge solar panels to make the most of the sparse sunlight, or some other source of power, like nuclear. Large solar panels pose a problem for a solar probe, though, because the panels would need to be shielded during solar encounters to avoid overheating. The size of a solar panel required to power the spacecraft out near Jupiter is too big to effectively stow near the Sun, so they'd have to be jettisoned at perihelion — and that limits you to just one solar pass, once you've lost your source of power. With nuclear power — a radioisotope thermoelectric generator, or RTG, the same source that powers deep-space missions like Cassini and New Horizons — performing a Jupiter gravity assist is a viable option.

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Changing the mission paradigm

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But the mission design was soon to change. David McComas, chair of the definition committee, remembers a call from Andy Dantzler, then project manager for the Solar Probe mission at APL. Dantzler passed away in 2011 at age 49; the Delta IV Heavy rocket that carried Parker Solar Probe to space was dedicated to him.  

"Andy asked if there was any way the committee might go for a mission wh ere you stay in the ecliptic plane but have lots of passes by the Sun and slowly reduce the perihelion," said McComas, who is now the principal investigator of the mission's Integrated Science Investigation of the Sun, or ISʘIS, suite and a professor of astrophysical sciences at Princeton University in New Jersey.

This was an entirely new paradigm for the mission. A hallmark of the original plan was passing over the Sun's poles, the source of the Sun's fast solar wind but a region of relative mystery to scientists. Additionally, staying in the ecliptic plane would almost certainly mean ending up farther from the Sun than had previously been anticipated.

"If you're trading perihelion distance, you have to swap it for something that will give you opportunities to fill in the science in some other way," said McComas.

Subsequently, two developments supported the choice to make these changes to the orbit and create the Parker Solar Probe mission we know today.

The first was new research published in 2009 by Thomas Zurbuchen — then a scientist at the University of Michigan and now the associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. This research showed that the solar wind that could be measured from the ecliptic plane was actually from a diverse mix of sources. It was not only the slower solar wind known to be more common near the Sun's equator, but also the high-speed solar wind that often originates closer to the Sun's poles. By sampling the solar wind from the ecliptic plane over a period of years, scientists could learn about this fast solar wind in ways they hadn't previously anticipated.

The second development was the shift that made such sampling possible: the design of Parker Solar Probe's current trajectory.  

"When starting, I had no clue if I could find a solution," said Guo, the mission trajectory designer. "Everybody thought Jupiter was the only practical way you could get closer to the Sun, within 10 solar radii."

In 2007, she came up with five alternative options that would keep the spacecraft near the ecliptic plane and would not require traveling out to Jupiter. These trajectory options used some combination of Earth and Venus gravity assists to gradually draw the spacecraft closer to the Sun over the course of a number of years. One fulfilled all the requirements for the Solar Probe mission — a total mission duration under 10 years, with a final close approach clocking in under 10 solar radii (equivalent to 4.3 million miles). This was chosen as the trajectory of the current mission, now called Parker Solar Probe after Dr. Eugene Parker, including seven Venus gravity assists that spiral the orbit in closer and closer to the Sun over the mission's seven-year lifetime.


The final orbit for the Parker Solar Probe mission uses seven Venus gravity assists to rack up more than 900 hours close to the Sun. The original mission concept, using a single Jupiter gravity assist, got the spacecraft closer to the Sun, but gave scientists less than 100 hours in key areas.
Credits: NASA's Goddard Space Flight Center/Mary Pat Hrybyk-Keith

 Download the Parker Solar Probe orbits infographic

The biggest hurdle to overcome for a trajectory with such repeated gravity assists is phasing. Of course, Venus is in constant motion around the Sun, so every time the spacecraft passes the planet and swings around our star, Venus is in a completely different place. But Guo's design solves that problem, with multiple opportunities for launch. This trajectory design carries the spacecraft through 24 orbits around the Sun. The seven Venus gravity assists happen at different points in the spacecraft's orbit, to account for the phasing problem — some, like the one on Oct. 3, happen as the spacecraft heads towards the Sun, while the others happen as Parker Solar Probe speeds away from the Sun.

This orbit is decidedly different than the original single-Jupiter-gravity-assist concept. Rather than two passes over the Sun's poles, coming within 1.23 million miles of the surface, this version of the mission provides 24 passes around the Sun near its equator, coming within 3.83 million miles of the Sun's surface.

Though Parker Solar Probe doesn't get as close to the Sun, this version of the trajectory provides the spacecraft with more than 900 hours in this critical inner region of the Sun's corona, within 20 solar radii (about 8.65 million miles). In comparison, earlier designs using Jupiter gravity assists provided less than 100 hours in this region.

"Here was this technical solution that was safer and cheaper and a better scientific mission because of all the samples we'd be getting," said McComas. "The Sun isn't a stable object — it's variable — so this would let us do a better scientific job."

This change to the mission also solved the power problem. Instead of requiring an RTG or unmanageably-large solar panels, Parker Solar Probe is powered by a pair of articulated solar panels that are slowly drawn into the shadow of the heat shield as the spacecraft approaches the Sun. At closest approach, only a small area remains exposed to generate the needed power for the spacecraft, cooled by the mission's first-of-its-kind solar array cooling system.

But though it solved a major problem, rethinking the mission in this way also required a complete rethinking of the spacecraft itself.

"The whole spacecraft design changed dramatically," said Nicola Fox, formerly the mission's project scientist at APL. Fox is now the director of the heliophysics division at NASA Headquarters. "With the earlier trajectory, the heat shield was the spacecraft. It was like a cone, with the pointed end facing the Sun, because when you're doing such a fast polar orbit it's tough to keep a shield oriented correctly."

"We aren't going in as far with the new trajectory, so we could go to a simpler shape for the heat shield, because it's possible to keep the heat shield oriented between the spacecraft and the Sun at all times. The whole thing looks really different."

The mission team credits Andy Dantzler with guiding them through this fundamental change in the mission's design that led to the mission we know today.

"When Andy called and asked if the definition team would go for it, I really didn't know the answer," said McComas. "As our definition team worked through the science, I became convinced that it wasn't just an equivalent mission, but actually a better scientific mission, because we get so much more time close to the Sun and so many more samples at different times."

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The first flyby

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During the Oct. 3 gravity assist, Parker Solar Probe came within about 1,500 miles of Venus' surface, reaching this closest point at about 4:45 a.m. EDT.  

Venus is an interesting case for heliophysicists, who study not only the Sun, but also its effects on planets. Unlike Earth, Venus doesn't have an internal magnetic field — instead, a weak magnetic field is induced over the surface by the constant barrage of solar charged particles flowing over the planet and interacting with its very dense atmosphere.

This first flyby offered a unique opportunity for calibration, as Parker Solar Probe flew through the trailing end of Venus' magnetic field, called the magnetotail.  Three of Parker Solar Probe's four instrument suites — SWEAP, ISʘIS and FIELDS — gathered data during the flyby on particles and fields in this region.  

Though the data is still making its way back to Earth, the science team hopes to analyze it before they set their sights on Parker Solar Probe's next major celestial encounter: its first close approach to the Sun. Parker Solar Probe's first solar encounter will happen Oct. 31 – Nov. 11, with the closest approach happening on Nov. 5 at a distance of 15 million miles from the Sun. The science data from this encounter will start downlinking to Earth in early December.

Parker Solar Probe is part of NASA's Living with a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living with a Star program is managed by the agency's Goddard Space Flight Center in Greenbelt, Maryland, for NASA's Science Mission Directorate in Washington. APL designed, built and operates the spacecraft.

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By Sarah Frazier
NASA's Goddard Space Flight Center, Greenbelt, Md.

Last Updated: Oct. 4, 2018
Editor: Rob Garner

[hlynin]

— Том Рисен. «Отправлен на Солнце» (Tom Risen, Taking on the Sun) (на англ.) «Aerospace America», том 56, №8, 2018 г., стр. 42-43 в pdf - 599 кб
 «Когда инженеры приступили к работе над солнечным зондом NASA Parker десятилетие назад, им нужно было создать теплозащитный экран, который был бы легким, отражающим и достаточно прочным, чтобы космический корабль стал первым, кто полетел в самую внешнюю атмосферу солнца, называемую короной, и разгадал загадку того, почему эта область более горячая, чем та, которая ближе к поверхности».

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https://blogs.nasa.gov/parkersolarprobe/2018/10/17/in-first-for-a-spacecraft-parker-solar-probe-autonomously-manages-heat-load-on-solar-arrays/

In First for a Spacecraft, Parker Solar Probe Autonomously Manages Heat Load on Solar Arrays

Sarah Frazier
Posted Oct 17, 2018 at 1:07 pm


Members of the Parker Solar Probe team examine and align one of the spacecraft's two solar arrays on May 31, 2018. Credit: NASA/Johns Hopkins APL/Ed Whitman

Two days after Parker Solar Probe flew past Venus toward its rendezvous with the Sun, the spacecraft had drawn close enough to our star that its power-generating solar array wings began to tilt themselves inward – a task directed by the spacecraft itself, based on the rising temperatures – away from the Sun and behind the spacecraft's heat shield. This is the first time that autonomous, closed-loop solar array angle control based on temperature has taken place on a spacecraft.

This solar array movement, controlled by software within the spacecraft's main processor, began on Oct. 5, soon after Parker Solar Probe's distance from the Sun dropped below about 65 million miles.

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Jonathan McDowell‏Подлинная учетная запись @planet4589 51 мин. назад

Parker Solar Probe has now fallen inside the orbit of Mercury and has picked up speed to 50.3 km/s (heliocentric; 181,000 km/hr). On Nov 5 it'll break the speed record of 68.6 km/s set by Helios 2 in 1976 and at perihelion Nov 6 at 0330 UTC it will set a new record of 95.3 km/s

Jonathan McDowell‏Подлинная учетная запись @planet4589 34 мин. назад

Parker Solar Probe has now fallen inside the aphelion of Mercury and has picked up speed to 50.3 km/s (heliocentric; 181,000 km/hr). On Oct 30 it'll break the speed record of 68.6 km/s set by Helios 2 in 1976 and at perihelion Nov 6 0330 UTC will set a new record of 95.3 km/s

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Jonathan McDowell‏Подлинная учетная запись @planet4589 18 мин. назад

Here are the orbits of Parker (magenta) and Mercury (blue) with their current positions indicated by the small magenta and green squares, and the Sun as the red square at (0,0)

Jonathan McDowell‏Подлинная учетная запись @planet4589 35 мин. назад

Here are the orbits of Parker (magenta) and Mercury (blue) projected on the ecliptic plane with their current positions indicated by squares. The Sun is the circle at (0,0).

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Jonathan McDowell‏Подлинная учетная запись @planet4589 43 мин. назад

Relative to Earth (which you should not care about, but I know some of you do) Parker will break the Helios 2 record of 98.9 km/s early on Nov 5 and set a new record of 109.9 km/s on Nov 7 around 1900 UTC.


42 мин. назад

The new records will of course soon be broken by Parker's later, faster orbits around the Sun in 2020 and later


41 мин. назад

Although Parker is still outside Mercury's *average* distance to the Sun, since Mercury is near aphelion right now, it's actually inside Mercury's *current* distance to the Sun.

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https://www.nasa.gov/feature/goddard/2018/parker-solar-probe-looks-back-at-home

Oct. 24, 2018

Parker Solar Probe Looks Back at Home

On Sept. 25, 2018, Parker Solar Probe captured a view of Earth as it sped toward the first Venus gravity assist of the mission. Earth is the bright, round object visible in the right side of the image.


The view from Parker Solar Probe's WISPR instrument on Sept. 25, 2018, shows Earth, the bright sphere near the middle of the right-hand panel. The elongated mark toward the bottom of the panel is a lens reflection from the WISPR instrument.
Credits: NASA/Naval Research Laboratory/Parker Solar Probe

The image was captured by the WISPR (Wide-field Imager for Solar Probe) instrument, which is the only imaging instrument on board Parker Solar Probe. During science phases, WISPR sees structures within the Sun's atmosphere, the corona, before they pass over the spacecraft. The two panels of WISPR's image come from the instrument's two telescopes, which point in slightly different directions and have different fields of view. The inner telescope produced the left-hand image, while the outer telescope produced the image on the right.  


A close-up of Earth from WISPR's Sept. 25, 2018, image shows what appears to be a bulge on our planet's right side — this is the Moon.
Credits: NASA/Naval Research Laboratory/Parker Solar Probe

Zooming in on Earth reveals a slight bulge on the right side: that is the Moon, just peeking out from behind Earth. At the time the image was taken, Parker Solar Probe was about 27 million miles from Earth.

The hemispherical shaped feature in the middle of the right-hand image is a lens flare, a common feature when imaging bright sources, which is caused by reflections within the lens system. In this case, the flare is due to the very bright Earthshine. Close passes by Venus and Mercury may occasionally create similar patterns in the future, but these are limited cases and do not affect the science operations of the instrument.

Some of the visible objects in the image — like Pleiades to the low-left of Earth in the right-hand image and the two bright objects, Betelgeuse and Bellatrix, near the bottom of the left-hand image — appear elongated because of reflections on the edge of the detector.

By Sarah Frazier
NASA's Goddard Space Flight Center, Greenbelt, Md.

Last Updated: Oct. 24, 2018
Editor: Rob Garner

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https://tass.ru/kosmos/5735663

Американский зонд побил рекорд приближения к Солнцу, установленный космическими аппаратами
ВАШИНГТОН, 30 октября. /Корр. ТАСС Дмитрий Кирсанов/. Американская автоматическая станция имени Юджина Паркера побила рекорд приближения к Солнцу, установленный космическими аппаратами. Об этом сообщило Национальное управление США по аэронавтике и исследованию космического пространства (NASA).
По его свидетельству, станция, предназначенная для исследования звезды, превзошла 29 октября примерно в 13:04 по времени Восточного побережья США (20:04 мск) прежнее достижение такого рода, принадлежавшее германо-американскому зонду Helios 2. Последний 17 апреля 1976 года приблизился к Солнцу на 43,4 млн км. На сколько именно зонд Паркера обошел державшийся 42 года рекорд, не уточняется. NASA, впрочем, подчеркивает, что теперь аппарат будет подлетать к Солнцу в ходе своей рассчитанной на семь лет миссии все ближе и ближе.
"Прошло всего 78 дней с момента запуска зонда имени Паркера, а мы уже подобрались к нашей звезде ближе, чем какой-либо другой космической аппарат в истории, - заявил руководитель проекта Энди Дрисмэн из Лаборатории прикладной физики Университета Джонса Гопкинса. - Команда горда, но мы продолжаем концентрировать внимание на нашем первом контакте с Солнцем, который начинается 31 октября". В этот день станция начнет подбираться все ближе к поверхности Солнца, пока не достигнет 5 ноября своего первого перигелия - ближайшей к Солнцу точки орбиты.
Зонд стартовал 12 августа с космодрома на мысе Канаверал (штат Флорида), он отправился в космос с помощью тяжелой ракеты-носителя Delta IV. Дата запуска несколько раз сдвигалась, в том числе для дополнительного тестирования программного обеспечения систем станции.

Детали миссии
Планируется, что в 2024 году зонд приблизится к Солнцу на расстояние около 5 млн км.

Спойлер

Это означает, что он будет находиться в пределах короны Солнца, то есть внешних слоев его атмосферы, где температура может достигать 500 тыс. кельвинов (около 500 тыс. градусов Цельсия) и даже нескольких миллионов кельвинов.
По замыслу американских ученых, в период по июнь 2025 года зонд совершит 24 витка по орбите вокруг Солнца, разгоняясь до скорости 724 тыс. км в час. На каждый такой виток у него будет уходить 88 дней.
На борту аппарата размером с небольшой автомобиль и стоимостью порядка $1,5 млрд размещено четыре комплекта научных инструментов. При помощи этой аппаратуры специалисты рассчитывают, в частности, осуществить различные измерения солнечной радиации. Наряду с этим станция должна будет передать фотоснимки, которые станут первыми, сделанными в пределах солнечной короны. Оборудование зонда защищено оболочкой из углепластика толщиной 11,43 см, позволяющей выдержать температуру до примерно 1,4 тыс. градусов Цельсия.
Как признала в июне прошлого года прежний координатор проекта Никола Фокс, его удалось реализовать только теперь благодаря появлению новых материалов, использованных в первую очередь при создании термостойкого щита зонда. Станция получила и новые панели солнечных батарей, уточнила Фокс. "Мы наконец прикоснемся к Солнцу", - эмоционально сказала эксперт, ставшая в сентябре директором управления гелиофизики NASA. По ее выражению, зонд поможет ученым понять, "как работает Солнце".

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Значение проекта

Спойлер

NASA обещает, что миссия произведет революцию в представлении человека о процессах, протекающих на Солнце. Претворение в жизнь намеченных планов позволит внести "фундаментальный вклад" в понимание причин "нагревания солнечной короны", а также возникновения солнечного ветра (потока ионизированных частиц, истекающего из солнечной короны) и "ответить на критически важные вопросы в гелиофизике, которые уже на протяжении нескольких десятилетий имеют высший приоритет", убеждено NASA. Информация с борта аппарата, по мнению его специалистов, будет иметь огромную ценность и с точки зрения подготовки дальнейших пилотируемых полетов за пределы Земли, поскольку позволит прогнозировать "радиационную обстановку, в которой предстоит работать и жить будущим покорителям космоса".
Зонд назван в честь американского астрофизика Юджина Паркера, которому летом исполнился 91 год. Ученый до сих пор ведет научную деятельность в Университете Чикаго (штат Иллинойс). Паркер стал одним из первых в мире специалистов, занимавшихся исследованиями солнечного ветра. С 1967 года он является членом Национальной академии наук США.

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Предполагается, что зонд Паркера подлетит в семь раз ближе к Солнцу, чем какой-либо другой из космических аппаратов, ранее отправлявшихся человеком.

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https://twitter.com/NASASun/status/1058438091160121346

On Oct. 31, #ParkerSolarProbe began its first solar encounter. During this phase, which lasts through Nov. 11, we'll be mostly out of contact with the spacecraft as it collects science data and flies to within just 15 million miles of the Sun's surface: https://blogs.nasa.gov/parkersolarprobe/2018/10/31/parker-solar-probe-starts-first-solar-encounter/ ...

12:18 - 2 нояб. 2018 г.

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Jonathan McDowell‏Подлинная учетная запись @planet4589 20 ч. назад

At 0328 UTC (0330 TDB) Nov 6, Parker Solar Probe passed through perihelion, setting new closeness-to-Sun and heliocentric speed records of 24.8 million km and 95.33 km/s respectively. It is now receding from the Sun and slowing down as it heads out to aphelion [Revised data]

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https://blogs.nasa.gov/sunspot/2018/11/07/how-to-be-an-orbital-mechanic-reading-orbit-plots-with-parker-solar-probe/

How to Be an Orbital Mechanic: Reading Orbit Plots with Parker Solar Probe

Miles Hatfield
Posted Nov 7, 2018 at 1:09 pm

By Dr. Tom Bridgman
NASA's Goddard Space Flight Center

On Oct. 29, 2018, at about 1:04 p.m. EDT, Parker Solar Probe became the closest spacecraft to the Sun, breaking the record of 26.55 million miles fr om the Sun's surface set by the Helios 2 in April 1976. But this is just the beginning. Parker Solar Probe — NASA's mission to touch the Sun — will get closer still.

This process is the result of carefully planned orbital mechanics, which will result in 24 passes around the Sun. Parker starts off in an orbit around the Sun which is the same as Earth's – that's where it starts, after all – and gradually moves to a position inside the orbit of Mercury. To do this, the spacecraft must slow down significantly (see Figure 1).


Figure 1: Parker Solar Probe orbit in the plane of the solar system. Parker orbit data fr om JHU Applied Physics Lab. Solar system orbit data from JPL/NAIF.

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One of the fundamental principles of orbital dynamics is that if you want to change the periapsis, or point of closest approach, of an elliptical orbit, you get the most bang for your buck if you change speed at the apoapsis, or the point when you're furthest away.

You can see this principle applied in the case of Parker Solar Probe. Figure 2 below plots Parker's orbital velocity on the y-axis (how fast it's moving relative to the Sun, in kilometers per second, km/s), with time plotted along the x-axis. Parker is represented by the purple curve; Mercury (black curve) and Earth (blue curve) are included for reference. [Click on the graph to see a full-size version.]


Figure 2: Parker Solar Probe orbit speed plotted with inner solar system planets for comparison. Parker orbit data from JHU Applied Physics Lab. Solar system orbit data from JPL/NAIF.

The first thing you'll notice is that the purple line is moving up and down quite a bit, indicating changes in its orbital velocity: Parker doesn't travel at a constant speed throughout its orbit, but rather speeds up and slows down at different points.

The little dots that appear at the spikes and the dips on the curve mark the times when Parker is either furthest from or closest to the Sun on each orbit. The aphelion positions, when Parker is farthest away from the Sun, are marked with red dots: Note that they coincide with the dips in the curve, when Parker has its slowest speed. The perihelion, or close approaches, are marked with green dots, and coincide with the spikes in the graph, wh ere Parker is traveling fastest.

Over time, you can see that the spikes get taller: Parker's speed at perihelion gets faster and faster. Although the graph doesn't directly show this, these increases in speed correspond to Parker's perihelion moving closer and closer to the Sun: The closer it gets, more of the Sun's gravitational energy gets translated into the spacecraft's energy of motion, increasing its speed. Parker launched from Earth orbit with a speed of about 17 kilometers per second (38,000 miles per hour), slower than the orbital speed of Earth (about 29 kilometers per second or 65,000 miles per hour), enabling it to 'fall' towards the Sun. Accelerating in the Sun's gravity, it reached a speed of over 95 kilometers per second (212,000 miles per hour) at the first closest approach. But looking at the graph, we see that Parker will go faster (and closer) still, its final orbit approaching over 190 kilometers per second (425,000 miles per hour).

But how does Parker keep getting closer? Getting closer to the Sun doesn't come for free — each shift in the orbit requires the help of gravitational assists from Venus. Note on the graph above that every time the spacecraft transitions to a higher speed at perihelion, or spike in the curve, there is a prior speed decrease near aphelion, or the dip in the curve, marked on the plot by a thicker red line. For Parker, these speed changes are accomplished with fly-bys of the planet Venus near Parker's aphelion position. Unlike many gravity assists wh ere spacecraft gain energy from sling-shotting around a planet, Parker is losing energy to Venus in order to slow down. By slowing down at aphelion, the orbit's overall size decreases, which in turn increases the spacecraft's speed near the Sun.

Parker doesn't fly by Venus on every single orbit, it will only go past the planet seven times over the course of seven years – but you can spot the flybys in the graph by noticing a small jag in certain spots. If Parker is accelerating towards the Sun — i.e., on the upward slopes in the graph, after the dip in a curve — the flyby appears as a little jag in the orbit, like the one just after October 2019 and October 2021. However, some flybys occur while the spacecraft is outbound from the Sun and decelerating, like the one near July 2020, which is a little less obvious in the plot. Each jag represents Parker moving just a bit slower, just a bit closer to the Sun – on each orbit gathering unprecedented, in situ observations of the star we live with.

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Зонд НАСА передал на Землю первый после сближения с Солнцем сигнал
07:52 08.11.2018

ВАШИНГТОН, 8 ноя – РИА Новости. Зонд НАСА Parker Solar Probe успешно перенес сближение с Солнцем и передал первый сигнал на Землю, сообщили в американском космическом ведомстве.

Parker Solar Probe приблизился к Солнцу на расстояние 24 миллионов километров, став первым из созданных человеком космических кораблей, достигшим такого расстояния от звезды. В среду во второй половине дня специалисты миссии получили первый сигнал от зонда.

"Полученный сигнал – сигнал А — является лучшим из всех возможных и свидетельствует, что Parker Solar Probe действует нормально и все его инструменты работают и собирают данные и, если и были незначительные проблемы, они были решены аппаратом автоматически", — сообщили в НАСА.

В понедельник аппарат достиг рекордной скорости в 343 тысяч километров в час. "Наряду с достижением максимального приближения к Солнцу, Parker Solar Probe будет повторно бить собственные скоростные рекорды по мере того, как его орбита будет вести его еще ближе к звезде, и он будет двигаться быстрее и быстрее в перигелии (ближайшей к Солнцу точки своей орбиты)", — отмечают в НАСА.

Ранее, 29 октября, зонд стал самым близким к Солнцу из созданных когда-либо человеком аппаратов, побив принадлежавший немецко-американскому зонду Hellios 2 рекорд в 26 миллионов миль (41,8 миллиона километров).

Спойлер

Parker Solar Probe, названный в честь астрофизика Юджина Паркера, стартовал с Земли в августе текущего года. По расчетам создателей, в течение семи лет ему предстоит совершить 24 витка вокруг Солнца.

Зонд оснащен рядом инструментов, расположенных под массивным тепловым щитом, который должен защитить зонд от "солнечного ожога", в их числе камера, прибор для измерения магнитного и электрического поля в атмосфере Солнца, а также два инструмента для измерения и наблюдения за частицами "солнечного ветра".

Ранее в НАСА сообщили, что первые полученные им данные будут переданы на Землю в декабре.

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РИА Новости https://ria.ru/science/20181108/1532331835.html