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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tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20190708e_PPTD_approach3/
ЦитироватьApproach to the 2nd touchdown –Part 3: To go or not to go–

After the generation of the artificial crater on the surface of asteroid Ryugu using the Small Carry-on Impactor (SCI) on April 5, four operations were conducted to observe near the new crater. As was mentioned in Part 2, the third descent operation also successfully dropped a target marker at the touchdown candidate site. Finally, here we present "To go, or not to go, that is the question".

Although the first touchdown was successful, going for a second touchdown is "the question" because touchdown is a high-risk operation. This is especially true in the case of Ryugu, which has no large, flat areas. The spacecraft therefore needs precise control to avoid a collision in rocky locations. In short, just because we have succeeded in the past does not mean we can easily do so again.

The spacecraft is operating far into space, in a harsh environment and with a communication time too long for us to correct problems if they occur. We always operate alongside the risk of failure or breakdown. Therefore, our project members will always feel uneasy about the prospect of performing a touchdown. But being vaguely anxious does not make any progress. The situation needs to be considered fr om a scientific and technical standpoint.

Two major issues need to be considered. The first is whether the second touchdown has significant scientific and engineering merit. If there is little extra to be gained, and as the first touchdown was already successful, there is no point in performing this twice. A second issue is the risk of the touchdown operations. If the risk is high, then the descent would be reckless.

First, let's consider the scientific and engineering value of the second touchdown. Fr om the observations around the site of the artificial crater, it was clear that there is ejecta from the crater in the region wh ere the second touchdown is planned (Figure 1). In other words, if we go ahead with the touchdown, we will reliably be able to collect subsurface material from Ryugu. This is high scientific value. In addition, this would also result in samples being collected from multiple locations on the asteroid. This also adds to the scientific value as it gives more universal information about Ryugu, rather than the possibility you may have collected material from an unusual spot. From an engineering perspective, this will be the world's first collection of samples from multiple locations and also the first sample from below the surface. This naturally means the value is high. Combined, this confirmed that the science and engineering value of a second touchdown is significant.


[Open in a separate window]
Figure 1: Change in the surface reflectivity due to the artificial crater formed with the Small Carry-on Impactor (SCI). The black regions indicate areas that have darkened after the collision. The planned touchdown point is in the vicinity of C01-C in the figure; a region that has darkened after the generation of the artificial crater. That is, it is thought that subsurface material from the artificial crater has been deposited in this region. (※ Image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST and Kobe University.)

Next to consider is the risk of the operation. If this is too high, there is an argument that this is not a chance that should be taken. We therefore first sel ected places that touchdown could be performed near the artificial crater, and proceeded to collect detailed information on the topography of these touchdown candidate points during the low altitude descent operations. We also were able to drop a target marker at one of these locations. This eventually became the planned touchdown site.

The planned touchdown site is about 20m away towards the north from the artificial crater generated with the SCI. This is an area with a radius of about 3.5m, which was named C01-Cb by the project. There are dangerous boulders around the area and also substantial rock piles in C01-Cb. After estimating the height of these rocks, creating a three-dimensional map and confirming the danger during a touchdown operation, it was judged that there would not be a problem if the spacecraft were to touchdown in this region.

A further technical issue was that the amount of light received by the optical systems on Hayabusa2 (the Optical Navigation Camera – Wide angle, ONC-W1, and laser range finder, LRF) decreased during the first touchdown. This is thought to be due to dust that soared upwards at the time of touchdown and adhered to the instruments. To cope with this problem, we decided to compensate for the decrease in the amount of received light by lowering the altitude at which to switch to the affected optical system. We confirmed that this approach works well during the low altitude operations.

As a result of the above examination, it was confirmed that the risk during the second touchdown is equal or less than the risk of the first touchdown. Since the second touchdown is of high scientific and engineering value, we decided the project should perform a second touchdown to collect a sample fr om asteroid Ryugu. This was approved by ISAS on June 21 and by JAXA as a whole on June 25, whereupon is was decided to do a second touchdown.

The second touchdown will be attempted on July 11. We will proceed with our mission with care, but boldly go.

※Please use the displayed credit when reproducing these images. In the case wh ere an abbreviated form is necessary, please write "JAXA, University of Tokyo & collaborators".

Hayabusa2 Project
2019.07.08

tnt22

Ещё один адрес трансляции посадки на ТыТрубе (jaxasgm)

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 10 ч. назад

This Thursday (July 11), Hayabusa2 will touchdown on asteroid Ryugu to collect a 2nd sample. You can tune in to our webcast from 09:30 JST (01:30 BST / Wed. 20:30 EDT / 17:30 PDT) here: https://www.youtube.com/watch?v=hnJX9obXzPU&feature=youtu.be ...

And press briefing from 14:00 JST:
00:30 UTC (03:30 ДМВ) 11.07.2019

tnt22

https://tass.ru/kosmos/6648419
Цитировать10 ИЮЛ, 05:36
Японский зонд "Хаябуса-2" начал снижаться перед второй посадкой на астероид Рюгу

Примерно через 22 часа после начала снижения зонд окажется в 500 метрах от астероида и его переведут в автоматический режим управления

ТОКИО, 10 июля. /ТАСС/. Японский зонд "Хаябуса-2" ("Сокол-2"), находящийся вблизи отдаленного астероида Рюгу, в среду начал снижаться с орбиты на высоте 20 км, чтобы через сутки совершить вторую посадку на это космическое тело. Об этом сообщило Японское агентство аэрокосмических исследований (JAXA).

На первом этапе аппарат будет опускаться со скоростью 40 см в секунду, пока не приблизится к Рюгу на расстояние 5 км. После этого скорость уменьшится до 5 см в секунду. Контролировать проведение операции и корректировать траекторию движения японские специалисты смогут благодаря установленной на "Хаябусе-2" камере, однако сигнал от нее доходит до Земли только спустя 10 минут.

Примерно через 22 часа после начала снижения зонд окажется в 500 метрах от астероида. Затем из-за отсутствия возможности оперативно следить за поведением аппарата с Земли его переведут в автоматический режим управления. В качестве ориентира для посадки "Хаябусы-2" будет использовать сброшенную ранее на поверхность космического тела контрольную метку.

Само приземление должно продлиться всего несколько секунд. За это время зонд должен выстрелить в поверхность астероида металлической пулей, которая поднимет вверх пыль и фрагменты грунта. Их в свою очередь соберет установленный на аппарате специальный пылесос. После этого "Хаябуса-2" вернется в свое обычное положение на расстоянии 20 км от Рюгу.
Спойлер
Астероид находится между Землей и Марсом. "Хаябуса-2" был запущен к нему в декабре 2014 года с космодрома на японском острове Танэгасима. Особые надежды возлагаются на то, что там удастся обнаружить следы воды и органических веществ, что, как полагают, может помочь в разгадке тайны распространения жизни во Вселенной. Первая посадка на Рюгу успешно прошла в феврале. Тогда зонд смог собрать нужные образцы пород.

Предполагается, что аппарат весом около 600 кг ориентировочно в ноябре или декабре сойдет с орбиты астероида и отправится в обратный путь. В 2020 году он должен вернуться на Землю.
[свернуть]
https://ria.ru/20190710/1556368615.html
ЦитироватьЯпонский космический зонд "Хаябуса-2" начал снижение к астероиду Рюгу
05:55

ТОКИО, 10 июл – РИА Новости, Ксения Нака. Японский космический зонд "Хаябуса-2" начал снижение к астероиду Рюгу, сообщило Японское аэрокосмическое агентство (JAXA).
Цитировать"В 11.01 (05.01 мск) мы смогли убедиться в том, что космический зонд начал снижение из своей исходной точки, которая находится на высоте 20 километров. Как и планировалось, он начал снижение в 10.46 (04.46 мск). Скорость снижения составляет 40 сантиметров в секунду", - говорится в сообщении, размещенном на официальной странице JAXA в сети Twitter.
Зонд начал снижение с высоты в 20 километров от поверхности астероида. Как ожидается, двигаясь с крайне низкой скоростью от 40 до 10 сантиметров в секунду, что позволит с ювелирной точностью регулировать процесс снижения, зонд сможет приземлиться на заранее намеченную для этого площадку. Она находится в 20 метрах от центра искусственного кратера, который зонд создал на поверхности Рюгу в апреле этого года. Он стал первым в мире рукотворным кратером на поверхности космического тела. Теперь зонд должен собрать образцы породы, которую выбросило на поверхность при образовании кратера.

Ученые считают, что именно образцы породы, полученной из недр астероида, в большей степени сохраняющей свойства материи времен возникновения Солнечной системы, позволят человечеству приблизиться к разгадке образования Солнечной системы и появлению жизни.

Радиус участка, на который должен приземлиться "Хаябуса-2", всего около 7 метров, но именно здесь, по расчетам ученых, нет больших валунов, которые могли бы повредить зонд. Для того, чтобы скорректировать посадку, зонд выбросит маркер в двух метрах от площадки, который будет подавать световой сигнал и таким образом служить ориентиром для приземления.

Как ожидается, утром в четверг зонд сможет приземлиться на поверхность астероида.
Спойлер
В марте ученые выяснили, что на Рюгу есть водосодержащие минералы с элементами кислорода и водорода, что также стало событием в истории освоения человеком космического пространства. В феврале этого года зонд совершил первую посадку на астероид и взял пробы грунта с поверхности.

Космический зонд "Хаябуса-2" был запущен к астероиду Рюгу в 2014 году. Рюгу удален от Земли на 340 миллионов километров. Его диаметр составляет около 900 метров. Ученые считают, что обнаруженные в грунте Рюгу элементы помогут раскрыть загадку происхождения на Земле воды и органических элементов.
[свернуть]

tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20190710e_PPTD/
ЦитироватьThe 2nd touchdown

The 2nd touchdown operation will take place fr om July 9 – 11. Here, we describe the operation events and schedule (the operation is referred to as the "2nd touchdown" but denoted PPTD).

For discussion about the 2nd touchdown operation, please take a look at these recent articles on our website.
 (1) Approach to the 2nd touchdown –Part 1: observations near the touchdown point−
 (2) Approach to the 2nd touchdown –Part 2: details of the touchdown point−
 (3) Approach to the 2nd touchdown –Part 3: to go, or not to go−

The first shift for the 2nd touchdown starts on July 9, where the set-up for the descent will be completed. The actual descent will begin on July 10 at 10:46 JST (on-board time). Initially, the descent will begin at a velocity of 40cm/s, matching that in previous operations. At 21:06 JST, the altitude will reach about 5km, whereupon the descent will slow to about 10 cm/s. On July 11 at 09:40 JST, the altitude will have reduced to 30m and the spacecraft will start to hover. Touchdown will be at about 10:05 JST at the earliest, and about 10:45 JST at the latest. Immediately after touchdown, the spacecraft will rise at a speed of about 65 cm/s and return to the home position on July 12. The entire touchdown operation is shown in Figure 1.


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Figure 1: Outline of the 2nd touchdown operation. The switch to using the Laser Range Finder (LRF) will take place during the descent fr om 30m. The time of touchdown indicated with the * is estimated to be around 10:05 JST (onboard time) at the earliest and about 10:45 JST at the latest (image credit: JAXA).
Спойлер
Figure 2 shows the operation at low altitude in detail. When the altitude reaches 30m on July 11 at 09:40 JST, the spacecraft will hover and capture the position of the target marker. This is done autonomously, so we do not know in advance when the target marker will be captured but if this is about 09:51, then the spacecraft will start to descend immediately. At this point, the altitude is being measured by the laser altimeter (LIDAR) but during this next descent, the task will be taken over by the Laser Range Finder (LRF). The spacecraft will then descend while keeping the target marker in the center of the field of view. At 09:57 JST, the spacecraft will reach an altitude of 8.5m and begin to hover again.


[Open in a separate window]
Figure 2: Operation sequence at low altitude.
From an altitude of 8.5m to touchdown, the spacecraft will follow a parabolic trajectory as it descends due to the pull from Ryugu, but will appear to descend almost directly downwards as viewed from the asteroid surface. The times indicated by the asterisk * are an example for the case wh ere the operation proceeds at the fastest time and the actual time could be delayed by up to about 40 minutes. (Image credit: JAXA)

After hovering at an altitude of 8.5, the first step is to change the attitude of the spacecraft to the landing attitude. The landing attitude is basically an attitude parallel to the surface of the asteroid but –as with the first touchdown—the attitude is slightly raised on the ion engine side (opposite the sample capsule) of the spacecraft. In the project team, we refer to this as a 'tail-up' posture. Changing the attitude would cause the target marker to move towards the edge of the field of view, but the spacecraft moves horizontally while changing attitude to keep the target marker centralized. After the attitude change, the spacecraft moves further horizontally to directly above the center of the touchdown point. And, when all conditions are satisfied, the spacecraft starts to descend at 10:03 JST, reaching the surface at 10:05 JST, completes the touchdown and immediately begins to rise.

However, please remember that the times for altitudes of 30m or less described in Figure 2 and the above description are for an example case wh ere the spacecraft operation progresses most swiftly. When the 30m altitude is reaches, the spacecraft will operate autonomously. As the spacecraft will check each operation before proceeding, the time needed may be longer. This is why the touchdown time is about 10:05 JST at the earliest but could be as late as about 10:45 JST. The same is true for the other times listed, which may be up to 40 minutes behind the times given here.

Figure 3 shows an animation of the movement of the spacecraft from an altitude of 8.5m to touchdown.

http://www.hayabusa2.jaxa.jp/en/topics/20190710e_PPTD/img/PPTD_sequence_x16.mp4
[Open in a separate window (mp4, 3.7MB) ]
Figure 3: Motion of the spacecraft from an altitude of 8.5m to touchdown (16x speed). The green circle is the touchdown area, C01-Cb. The lower right image shows the area that falls within the field of view for the Optical Navigation Camera – Wide angle (ONC-W1). (Image credit: JAXA)

The touchdown location was named by the project team as C01-Cb. Please take a look at article (2) for details about this site. Figure 4 shows an animation of the Digital Elevation Map (DEM), which is a three-dimensional diagram of the surface near the touchdown point. Although C01-Cb is relatively flat, it can be seen that there are still large boulders around the site.

http://www.hayabusa2.jaxa.jp/en/topics/20190710e_PPTD/img/DEM_3d_view.mp4
[Open in a separate window (mp4, 5.6MB) ]
Figure 4: Animation of the DEM (Digital Elevation Map) near the second touchdown point. (Image credit※1: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST, Kobe University, University of Occupational and Environmental Health.)
[свернуть]
The 2nd touchdown is the last big operation at Ryugu for the Hayabusa2 project. We will proceed with caution and the upmost care. Please wish us success...!

Hayabusa2 Project
2019.07.10

※ Please use the displayed credit when reproducing these images..
※1 If an abbreviated form is needed, please write "JAXA, University of Tokyo & collaborators".

tnt22

Опубликованы материалы пресс-конференции 09.07.2019

Hayabusa2_Press20190709_ver8_en3.pdf - 2.2 MB, 25 стр, 2019-07-10 07:29:08 UTC





tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 15 ч. назад

[PPTD] July 10 at 11:01 JST. We have confirmed the spacecraft has started its descent from the home position (altitude of about 20km). The spacecraft begun its descent at 10:46 JST (onboard time) as scheduled. The descent speed is about 40cm/s.


12 ч. назад

[PPTD] July 10 at 14:04 JST. The spacecraft altitude is now about 15km. We are continuing to descend smoothly.


9 ч. назад

[PPTD] July 10 at 16:55 JST. The spacecraft altitude is now about 11km.


8 ч. назад

[PPTD] July 10 at 17:39 JST. The spacecraft altitude is now about 10km. Currently, there are about 20 members in the control room and the work is quiet. By the way, the one-way propagation time for a radio-wave to reach the spacecraft is about 815 seconds (13mins 35s) today.


6 ч. назад

[PPTD] July 10 at 20:28 JST. The altitude of the spacecraft is approximately 6km.


5 ч. назад

[PPTD] July 10 at 21:36 JST. Gate 2 check. It was confirmed that the spacecraft decelerated as planned (onboard 21:06 JST) and is descending at about 10 cm/s. Spacecraft and ground system were also confirmed to be normal and continuation of the operation is GO.

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 3 ч. назад

These amazing stereoscopic images are by @DrBrianMay & Claudia Manzoni. They show a particularly clear view of the large rock formation, Otohime Saxum. The top two images are with parallel stereoscopy and the bottom two use cross-eyed stereoscopy. Details: http://www.hayabusa2.jaxa.jp/en/topics/20190710e_Stereo_DrMay/ ...



tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 3 ч. назад

[PPTD] July 10 at 23:23 JST. The altitude of the spacecraft is now about 4km. This photo is a navigation image received at 23:05 JST.


tnt22

#951
ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 19 мин. назад

[PPTD] Hayabusa2 Live broadcast:
Time: Thursday. July 11 09:30 - 12:00 JST (Showing past operation clips from 09:00)

・Japanese (with live subtitles): https://fanfun.jaxa.jp/jaxatv/detail/14884.html ...
(Backup:
https://www.youtube.com/watch?v=QazGb1pIHMA ...)

・English (with simultaneous translation):
https://www.youtube.com/watch?v=hnJX9obXzPU ...

00:30 - 03:00 UTC 11.07.2019

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