Hayabusa 2 (Хаябуса-2), Procyon – H-IIA F26 – Танэгасима – 03.12.2014 04:22:04 UTC

Автор Космос-3794, 13.08.2010 10:49:07

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SashaBad

Так или иначе мы всё-таки будем там.

tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20180915e/
ЦитироватьThe spacecraft shadow and opposition effect

The first operation rehearsal for the first touchdown of Hayabusa2 was performed fr om September 10 - 12. The spacecraft reached an altitude of about 600 m from the surface of Ryugu and then began to ascend once again. During the operation, the images taken for navigation purposes with the Optical Navigation Camera Wide angle (ONC-W1) were released in real time. The last image captured is shown in Figure 1. This photograph was taken on September 12 at around 12:40 JST at an altitude of 635m from the surface of Ryugu.
Спойлер
 
[Enlargement (left, a)] [Enlargement (right, b)]
Figure 1: Ryugu captured with the ONC-W1 on September 12, 2018 at around 12:40 JST. The distance to the surface of Ryugu is about 635m. In this image, the south pole of Ryugu is at the top as the asteroid rotates in the opposite direction to the Earth. (b) The region within the red circle is brightened due to the opposition effect. The black dot indicated by an arrow is the shadow of Hayabsua2. (Image credit: JAXA).

In this image, the left-hand side (within the red circle in Figure 1b) appears brightened due to a phenomenon known as the "opposition effect". It is a phenomenon that occurs when the angle formed between the Sun - the celestial body surface - observation point (known as the "phase angle" ) is close to zero, resulting in the celestial body being illuminated from directly behind the observation point and creating a bright region. In the center of the bright part is a black dot but this is the shadow of Hayabusa2. The sunlight is behind the spacecraft, casting the shadow on the asteroid.

It is easier to see that this dot is the shadow of the probe in an animation. Figure 2 shows the image sequence of Hayabusa2's descent.

http://www.hayabusa2.jaxa.jp/en/topics/20180915e/img/Fig2.mp4
(video 0:09)
Figure 2: An animation created from images taken with the ONC-W1 during the time the spacecraft was approaching Ryugu (from September 11, 2018 at around 14:00 JST to September 12, 2018 at around 13:00 JST). (Image credit: JAXA)

The animation shows Ryugu increase in size during the approach and the shadow of Hayabusa2 can be seen near the end. Notice that the shadow of Hayabusa2 does not move even as Ryugu rotates and as the distance decreases, the shadow expands. It also appears to be fixed on the screen. To understand this, please check out the "A little more detail" section below.

Hayabusa2 is about 6m in size and is casting a shadow on a roughly 900m object, 300 million km from the Earth. That this could be captured in a photograph is quite breathtaking, don't you think? Hayabusa2 may only be small, but the spacecraft is very brave!

■A little more detail

Here we explain a little more about the motion of the shadow of Hayabusa2 and opposition effect. The relative position of the celestial bodies when Figure 1 was captured is shown in Figure 3. Since Hayabusa2 is in the immediate vicinity of Ryugu, it is in the same location as the marker for Ryugu but approaches the asteroid along the line connecting Ryugu to the Earth.


Figure 3: Arrangement of the celestial bodies on September 12, 2018. The figure is projected on the ecliptic plane (the plane in which the Earth orbits the Sun) along the north axis of the Solar System (also the North Pole of the Earth). In this figure, the celestial bodies revolve counterclockwise around the Sun. (Figure credit: JAXA).

If we enlarge the diagram near Ryugu, the system looks like that shown in Figure 4.


Figure 4: Schematic diagram close to Ryugu. (Figure credit: JAXA)

As shown in Figure 4, Hayabusa2 descends along the line connecting the Earth with the center of Ryugu. The Sun is shining diagonally from the right of the figure. As Hayabusa2 descends, the shadow of the spacecraft appears on the left side of Ryugu and moves to the right.

Since the sunlight can be thought of as parallel rays, the angle θ in Figure 4 hardly changes during the short time the spacecraft descends. This means that the direction in which the shadow can be seen remains almost the same during the descent so that it appears as if the position of the shadow is fixed in the animation shown in Figure 2.

We know that the Sun is in the opposite direction to wh ere shadows fall and that the surroundings directly opposite the Sun appear brighter than their surroundings. This is the opposition effect. Figure 5 shows a simplified schematic of this situation. When the angle formed by the direction of the Sun's rays and the line of sight (α: phase angle) is close to zero, the light reflected by the celestial body will be at its strongest.


Figure 5: Explanation of the opposition effect. (Figure credit: JAXA.)

The opposition effect was also seen when Hayabusa explored Itokawa (Figure 6).


Figure 6: The shadow of Hayabusa at the "Muses sea" (the official name is the MUSES-C Regio) on asteroid Itokawa and the opposition effect (November, 2005). (From http://www.isas.jaxa.jp/j/special/2008/hayabusa/11.shtml

If we approach Ryugu still closer, we should see the shadow of Hayabusa2 clearly as with the shadow of Hayabusa in Figure 6. This may be what we see on our next approach.
[свернуть]
Hayabusa2 project
2018.09.15

opinion

Цитироватьtnt22 пишет:
http://www.hayabusa2.jaxa.jp/en/topics/20180915e/
ЦитироватьThe animation shows Ryugu increase in size during the approach and the shadow of Hayabusa2 can be seen near the end. Notice that the shadow of Hayabusa2 does not move even as Ryugu rotates and as the distance decreases, the shadow expands.
Тогда у меня тоже вопрос. Хаябуса сейчас на расстоянии чуть больше одной астрономической единицы от Солнца. То есть угловой размер Солнца примерно такой же, как на Земле. Размеры Хаябусы около 5 метров. Если так, то с расстояния 635 метров и больше, она не могла отбрасывать полную тень. Значит, это полутень. Но если так, она же не должна увеличиваться, не так ли?
There are four lights

tnt22

http://www.hayabusa2.jaxa.jp/en/news/status/
ЦитироватьSep. 18, 2018

★ Hayabusa2 status(the week of 2018.09.10)★

The first half of the week was devoted to the landing rehearsal operation (TD1-R1). The operation was suspended at an altitude of 600m, and the spacecraft returned to the base camp 20 km home position. Although TD1-R1 was interrupted, we were able to see the response of Hayabusa2 at low altitude and gain a valuable image of the landing candidate area at high resolution. The Project Team feels that we are narrowing down the unexplored areas step by step. Our analysis of this data continues for the upcoming rover separation and landing operation.

2018.09.17 Y.T.

tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20180919e/
ЦитироватьThe small exploration rovers, MINERVA-II1

The MINERVA-II (standing for the "MIcro Nano Experimental Robot Vehicle for Asteroid, the second generation") are a successor to the exploration rover, MINERVA, that was installed with the first Hayabusa mission to asteroid Itokawa.

Two containers for MINERVA-II1 and MINERVA-II2 are mounted on the bottom of the Hayabusa2 spacecraft. Two rovers are stored within the MINERVA-II1 container and one rover sits in the MINERVA-II2 container (Figure 1). This September, the two MINERVA-II1 rovers within the first container will be deployed, while the MINERVA-II2 deployment is scheduled for next year.
Спойлер

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Figure 1: The bottom of the Hayabusa2 spacecraft. (Image credit: JAXA)

The two MINERVA-II1 rovers (Rover-1A, 1B) are hexagonal in shape with a diameter of 18cm, height of 7cm and weight of about 1.1 kg each (Figure 2). The pair were developed at the JAXA Institute of Space and Astronautical Sciences in collaboration with the following manufacturers, universities and organizations:

< Collaborating manufacturers, universities, organizations and related institutes>
Aichi University of Technology, University of Aizu, Addnics corp, Antenna Giken Co., Ltd, ELNA, CesiaTechno, University of Tokyo, Tokyo Denki University, Digital Spice Corp, Nittoh Inc., Maxon Japan, DLR, ZARM.


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Figure 2: The small rovers, MINERVA-II1. Rover-1A is on the left and Rover-1B is on the right. Behind the rovers is the cover in which they are stored. (Image credit: JAXA).

There are four cameras on Rover-1A and three cameras on Rover-1B. We are planning to use the cameras on each rover to create a stereo image of the surface of Ryugu. Some of the projections from the rover edge that looks like thorns are temperature sensors to measure the surface temperature of Ryugu. Additional instruments on the rovers include optical sensors, an accelerometer and a gyroscope.

The rovers communicate with Hayabusa2 using the repeater (OME-E) installed on the main spacecraft. The maximum communication speed is 32 kbps. Data received by Hayabusa is then transferred to the Earth. The OME-E will also be used for communication with the German/French lander, MASCOT, scheduled for deployment in October.

The main feature of MINERVA-II1 is the ability for the rovers to move on the surface of Ryugu by utilizing a hopping mechanism (Figure 3). Within the rover is a motor that rotates and causes the rover to "hop" (jump up) during the rebound. This will allow the rovers to move across the asteroid surface and explore multiple areas. On Ryugu, MINERVA-II1 will move autonomously, determining what should be done for the exploration by itself.


[open in another window]
Figure 3: Illustration of Rover-1A (back) and Rover-1B (foreground) from MINERVA-II1 as they explore the surface of Ryugu. (Image credit: JAXA)
[свернуть]
Gravity on the surface of Ryugu is very weak, so a rover propelled by normal wheels or crawlers would float upwards as soon as it started to move. Therefore this hopping mechanism was adopted for moving across the surface of such small celestial bodies. The rover is expected to remain in the air for up to 15 minutes after a single hop before landing, and to move up to 15 m horizontally.

Hayabusa2 project
2018.09.19

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 12 ч. назад

[MINERVA-II1] September 19 09:00 JST: Operations for the deployment of the MINERVA-II1 rovers begins today! Currently, ground communication is from Usuda. Preparation for the spacecraft descent will take place today, and from tomorrow the descent will begin. (Hayabusa2 Project)

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 14 мин. назад

[MINERVA-II1] September 20 at 12:30 JST: Operation for the deployment of MINERVA-II1 is underway. Communication is currently via the Usuda Deep Space Center. Today, the spacecraft will start to descend.

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 1 мин. назад

[MINERVA-II1] September 20 at 13:22 JST: GATE 1 check point: we have confirmed there are no issues and the operation will proceed. The spacecraft has not yet begun its descent.

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 13 мин. назад

[MINERVA-II1] September 20 at 14:26 JST: The start of the spacecraft descent from the home position (about 20 km altitude) as planned has been confirmed. The onboard descent start time was 14:08 JST and the descent speed is about 40 cm/s.

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 7 мин. назад

[MINERVA-II1] Hayabusa2 has started its descent and the images taken by the Optical Navigation Camera Wide angle (ONC-W1) for navigation are being released in real time at this gallery link: http://www.hayabusa2.jaxa.jp/en/galleries/onc/nav20180920/ ... [Image credit: JAXA]


Чебурашка

#450
Круть, посадку на далёкое тело чуть ли не в прямой эфире показывает.   8)  
Только частота кадров малая - 2 кадра в час

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 6 ч. назад

[MINERVA-II1] If you'd like to see our current plan for the MINERVA-II1 deployment, check out the schedule here! (Note exact times may shift depending on current operation conditions.) http://www.hayabusa2.jaxa.jp/en/topics/20180920e/ ...


tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 6 ч. назад

[MINERVA-II1] September 20 at 17:30 JST: The altitude of the probe is about 15km and communication is now from the Madrid Deep Space Network Communication Complex.
#asteroidlanding


59 мин. назад

[MINERVA-II1] September 20 at 21:03 JST: the altitude of the spacecraft is about 10km. The round trip communication time with Hayabusa2 is 35 minutes 22.6 seconds. Don't forget to take a look at our gallery of real time navigation images http://www.hayabusa2.jaxa.jp/en/galleries/onc/nav20180920/ ...
#asteroidlanding


35 мин. назад

[MINERVA-II1] September 20 at 22:30 JST: the spacecraft altitude has reached 8km. Operations are running 24 hours a day and we have just changed to the late night shift.
#asteroidlanding

кукушка

#453
https://naked-science.ru/article/sci/yaponskiy-zond-spustit-na-ryugu-dvuh


Японский зонд спустит на Рюгу двух прыгающих роботов
На этой неделе космический аппарат «Хаябуса-2» должен спустить на поверхность астероида Рюгу два маленьких ровера.

На прошлой неделе команда «Хаябуса-2» начала подготовку к серьезному этапу своей миссии. Согласно графику, 19 сентября аппарат должен был приблизиться к Рюгу, чтобы в итоге спустить на него два небольших дискообразных робота — MINERVA-II1A и MINERVA-II1B. Если не возникнет проблем, операцию проведут в ночь с 20 на 21 сентября.

Каждый ровер MINERVA-II весит 1,1 килограмма и обладает размерами 18 сантиметров в ширину и семь сантиметров в высоту. По поверхности астероида они будут передвигаться довольно необычным способом — перепрыгивая с места на место.  

 «Гравитация на поверхности Рюгу очень слабая, так что вездеход, передвигающийся на обычных колесах или гусеницах, стал бы «всплывать», как только начал бы движение, — сообщают члены команды «Хаябуса-2» в описании к MINERVA-II1. — Таким образом, мы адаптировали этот прыгающий механизм для передвижения по таким малым небесным телам. Ожидается, что после прыжка ровер будет находиться над поверхностью до 15 минут, прежде чем он опустится обратно на поверхность, переместившись на 15 метров по горизонтали».

 Вездеходы будут передвигаться автономно, исследуя поверхность 950-метрового Рюгу. При помощи научных инструментов, в том числе температурных и оптических сенсоров, акселерометров, гироскопов и семи камер на двоих, роботы соберут большой объем данных.

 В следующем году зонд «Хаябуса-2» также совершит несколько спусков на поверхность Рюгу для сбора материала. Орбитальный аппарат покинет астероид в декабре 2019-го и через год привезет на Землю образцы в специальной капсуле.

 Ученые детально изучат грунт и камни, чтобы узнать о ранней истории Солнечной системы и роли астероидов, которую они могли сыграть в зарождении жизни на Земле.

[/SPOILER]

Григорий Разгон

Удивительно, как при массе 1,1 кг, вес составит 18мг., это легче мелкой крупинки сахара, смогут управлять движением?

tnt22

ЦитироватьJonathan McDowell‏Подлинная учетная запись @planet4589 23 мин. назад

Hayabusa-2 has braked its approach speed from 0.4 m/s to 0.1 m/s; as of 1730 UTC Sep 20 it has just passed the 4 km mark on its approach to Ryugu. A naive calculation suggests it will reach the vicinity of the surface in another 11 hours!

tnt22

В 05:20 JST 21.09.2018 высота над поверхностью астероида составила 3 км:
Цитировать小惑星探査機「はやぶさ2」‏Подлинная учетная запись @haya2_jaxa 4 мин. назад

【MINERVA-Ⅱ1】9月21日 05:20JST:探査機の高度が3kmを切りました。JAXA相模原キャンパスでは、外が明るくなってきました。

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 22 мин. назад

[MINERVA-II1] September 20 at 23:50 JST: the altitude of the spacecraft is about 6 km. This is the fifth time to reach this altitude. The photograph shows Ryugu, taken with the ONC-W1 at around 23:20 JST. The little world is about 320 million km from the Earth.
#asteroidlanding




20 мин. назад

[MINERVA-II1] September 21 st 00:51 JST. Confirmation that the speed of the spacecraft has slowed to about 10 cm/s from 40 cm/s. We will now approach Ryugu more slowly. Communication has transferred from Madrid DSN to Goldstone DSN via uplink transfer.
#asteroidlanding


19 мин. назад

[MINERVA-II1] September 21 at 05:20 JST: The altitude of the spacecraft is now down to 3 km. At the JAXA Sagamihara campus, the sky outside is beginning to get brighter.


tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 7 ч. назад

[MINERVA-II1] September 21 at 09:30 JST. We have confirmation that the spacecraft has descended to an altitude of about 1.5 km as planned. Ryugu is starting to look big! This is an image captured with the ONC-W1 at about 09:00 JST.




6 ч. назад

[MINERVA-II1] September 21 at 11:00 JST: The altitude of the spacecraft is now at 900m. This image was captured at 10:30 JST. The shadow of Hayabusa2 is now visible! (Real-time display of the navigation images has stopped: please wait for recovery).




5 ч. назад

[MINERVA-II1] September 21 at 11:30 JST: The altitude of the spacecraft has decreased to about 700m. Here is the image taken at about 11:00 JST.




5 ч назад

[MINERVA-II1] September 21 at 11:50 JST: the spacecraft altitude as decreased to about 600m. This is a new minimum altitude!


5 ч. назад

[MINERVA-II1] September 21 at 12:05 JST. The altitude of the spacecraft has decreased to about 500 m.