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

« назад - далее »

0 Пользователи и 2 гостей просматривают эту тему.

tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20180927e_TD1R1/
ЦитироватьConfirmation of landing candidate sites from the rehearsal operation

From September 10 to 12, we conducted the Touchdown 1 Rehearsal 1 (TD1-R1) operation and were able to confirm the selection of the candidate sites for touchdown. Figure 1 shows an image taken from about 3km above the asteroid surface using the Optical Navigation Camera – Telescopic (ONC-T).

 
[Enlargement (left)] [Enlargement (right)]
Figure 1: Image of the touchdown candidate sites taken from about 3km above the surface using the Optical Navigation Camera – Telescopic (ONC-T). The image was captured on September 12, 2018 at around 06:00 JST. In the right-hand image, the approximate areas of the touchdown candidate sites are marked out. 
(Image credit※: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, Aizu University, AIST).

In the right-hand image of Figure 1, the areas for the touchdown candidate sites are marked out. L08 is the primary touchdown candidate site, while L07 and M04 are the back-up choices. Part of L07 extends slightly beyond the image, but most of that area is captured.

Touchdown operations will continue to be studied from now on.

Hayabusa2 project
2018.09.27

tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20180927e_MNRV/
ЦитироватьMINERVA-II1: Images from the surface of Ryugu

The MINERVA-II1 rovers were deployed on September 21 to explore the surface of asteroid Ryugu. Here is the second report on their activities, following our preliminary article at the start of this week. We end this report with a video taken by one of the rovers that shows the Sun moving across the sky as seen from the surface of Ryugu. Please take a moment to enjoy "standing" on this new world.

1. Rover-1B hop

  
[Open in another window (Left)]  [(Center)]  [(Right)]
Figure 1. Images taken by Rover-1B. September 23, 2018: confirmation of Rover-1B hop.
Observation time (JST): (Left) 2018-09-23 09:50, (Center) 2018-09-23 09:55, (Right) 2018-09-23 10:00
(Image credit: JAXA)

2. Image captured immediately before hop of Rover-1B


[Open in another window]
Figure 2. September 23, 2018: image captured immediately before hop of Rover-1B. 2018-9-23 09:46 (JST).
(Image credit: JAXA)

3. Surface image from Rover-1B after landing


[Open in another window]
Figure 3. September 23, 2018 at 10:10 JST: surface image from Rover-1B after landing
(Image credit: JAXA)

4. Surface image taken from Rover-1A


[Open in another window]
Figure 4. September 23, 2018 at 09:43 JST: surface image taken from Rover-1A
(Image credit: JAXA)

5. Rover-1A captured the shadow of its own antenna and pin

 
[Open left image in another window]
Figure 5. September 23, 2018 at 09:48 JST: surface image taken from Rover-1A. MINERVA-II1 successfully captured the shadow of its own antenna and pin.
(Image credit: JAXA)

The pins on the MINERVA-II rovers have three roles:
1. To increase friction when hopping
2. Protect the solar cells during landing
3. A few of the pins also have a temperature sensor, so surface temperature can be measured directly.

6. Rover-1B successfully shot a movie

http://www.hayabusa2.jaxa.jp/en/topics/20180927e_MNRV/img/rover1b_sol07_movie.mov
Figure 6. (movie) Rover-1B successfully shot a movie. 15 frames captured on September 23, 2018 from 10:34 – 11:48 JST.
(Image credit: JAXA)

Hayabusa2 project
2018.09.27

tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20180927e_HighestRes/
ЦитироватьRyugu surface image at highest resoltion so far

When Hayabusa2 descented to Ryugu for the MINERVA-II1 deployment operation, ONC-T (Optical Navigation Camera – Telescopic) captured the image at highest resolution so far.


[Open in another window]
Figure 1. Image of Ryugu captured by the ONC-T at an altitude of about 64m. Image was taken on September 21, 2018 at around 13:04 JST.This is the highest resolution photograph obtained of the surface of Ryugu. Bottom left is a large boulder.
(Image credit※: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, Aizu University, AIST).

Next figure shown the place of Figure 1 on Ryugu.

[Open in another window]
Figure 2. Region of the highest resolution image. Yellow boxes corresponds to the region of Figure 1. (Left) The region is shown on ONC-T image of Ryugu globe. (Right) ONC-W1 image, taken at 70 m height. 2018-09-21 13:02(JST).
(Image credit※: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, Aizu University, AIST).

Note: Highest resolution image obtained by Haybusa


[Open in another window]
Figure 3. High resolution image of the surface of asteroid Itokawa photographed by Hayabusa. "D" is taken from an altitude of 63m. It is thought that the so-called "Muses Sea" (official name "MUSES-C Regio" ) is covered with a "gravel" of granules with diameters from a few mm to few cm. 
(From Yano et al, Science Vol 312 2, June 2006)

Hayabusa2 project
2018.09.27

tnt22

https://ria.ru/science/20180927/1529483906.html
ЦитироватьОпубликовано первое в истории видео с поверхности астероида
16:41 27.09.2018 (обновлено: 17:35 27.09.2018)

МОСКВА, 27 сен – РИА Новости. Пара роверов MINERVA-II1 передали на Землю новые фотографии с поверхности астероида Рюгю, а также небольшое видео, сообщает на своем сайте японское агентство аэрокосмических исследований JAXA.

"Своеобразные "шпильки", которые можно увидеть на одной из фотографий, украшают поверхность роверов не просто так, они решают сразу три задачи. Они помогают сильнее цепляться за поверхность астероида во время прыжка, защищают солнечные батареи от повреждений и содержат датчики температур", — отмечают специалисты агентства.
Автоматическую станцию "Хаябуса-2" запустили в космос в декабре 2014 года для изучения и забора проб на астероиде Рюгю. Как надеются ученые, она привезет на Землю первые абсолютно чистые образцы первичной материи Солнечной системы.

Японский аппарат достиг цели в начале июня и начал длительную процедуру торможения и сближения с астероидом.


© Фото : JAXA
Тень антенны и шпиля ровера MINERVA-II1

Забор грунта, несмотря на то, что "Хаябуса-2" давно достигла Рюгю, произойдет только через несколько недель. Сначала зонд должен определить положение на орбите и скорректировать ее, если возникнет такая необходимость, а затем — всесторонне изучить структуру недр и рельеф астероида.

Только после этого межпланетная станция сблизится с поверхностью Рюгю и сбросит на нее своеобразный "взрывпакет", который выбросит нетронутый материал из недр астероида. "Хаябуса-2" соберет эту пыль и гальку, левитирующую в вакууме, во время второго пролета над точкой.
Спойлер

© Фото : JAXA
Поверхность астероида Рюгю

Помимо этого, "Хаябуса-2" доставила к астероиду три спускаемых аппарата – два японских ровера MINERVA-II1, аналог которых был отправлен к астероиду Итокава вместе с "Хаябусой-1" в далеком 2003 году, а также европейский аппарат MASCOT.

Роботы Rover-1A и Rover-1B успешно достигли поверхности Рюгю в минувшие выходных. Они сделали множество фотографий и собрали массу научных данных, которые сейчас обрабатываются специалистами JAXA.

Новая порция фотографий, а также первое в истории видео с поверхности астероида, передали на Землю в середине недели после очередного "прыжка" роверов по поверхности Рюгю. Пока все инструменты и солнечные батареи аппаратов работают нормально.

В начале октября к ним присоединится европейский MASCOT. Он совершит посадку в районе экватора, приступит к изучению структуры недр Рюгю и к наблюдению за магнитными полями.


© Фото : JAXA
Поверхность астероида Рюгю
[свернуть]

tnt22


tnt22

ЦитироватьGet ready for AsteroidLanding! (Mascot Trailer)

DLR

Опубликовано: 26 сент. 2018 г.

MASCOT is a lander on board the Japanese Hayabusa2 spacecraft. The destination of the mission is the asteroid Ryugu. MASCOT will touch down on the surface, 'hop' from location to location, and carry out measurements at various points on an asteroid for the frst time in history.

+++ We are landing on asteroid Ryugu on 3. 10. 2018 +++
https://www.youtube.com/watch?v=q4oenCRPFZAhttps://www.youtube.com/watch?v=q4oenCRPFZA (2:33)

tnt22

ЦитироватьIN SEARCH OF THE ORIGINS OF LIFE - Mission Hayabusa2 & Mascot

DLR

Опубликовано: 27 сент. 2018 г.
https://www.youtube.com/watch?v=Ww7l4q50dEchttps://www.youtube.com/watch?v=Ww7l4q50dEc (8:15)

tnt22


tnt22

ЦитироватьMASCOT Lander‏Подлинная учетная запись @MASCOT2018 5 ч. назад

MARA radiometer - https://www.dlr.de/pf/en/desktopdefault.aspx/tabid-8654 ...
#asteroidlanding #hayabusa2

https://www.dlr.de/pf/en/desktopdefault.aspx/tabid-8654
ЦитироватьMascot radiometer (MARA)

The DLR Institute for Planetary Research provides a radiometer and a camera for the MASCOT Lander, which is being developed in cooperation with the French space agency CNES. MASCOT is part of the scientific payload of JAXA's Hayabusa II mission, which will investigate the near Earth asteroid 1999JU3 in 2018, to bring back samples in 2020. Apart from the camera and radiometer, MASCOT is equipped with a spectrometer and magnetometer. The measurements to be performed will characterize the asteroid on small scales in situ, and help to choose a site for sample collection.

The MASCOT radiometer MARA measures the radiometric flux emitted from the asteroid's surface in 6 different infrared bands (Figure 1). Two long-pass channels are used to determine the surface brightness temperature, while 4 bandpass channels will determine the spectral characteristics of the surface. A comparison with spectra measured in the laboratory will then allow for a characterization of surface materials and the asteroid's composition.


Figure 1: Sensorhead of the MASCOT radiometer (MARA) with the aperture cover removed (on the right hand side of the picture). The sensor head houses 6 thermopile sensors, each equipped with its own infrared filter to determine the radiometric flux at different wavelengths.


Figure 2: Interior of a thermopile sensor. The black absorber surface has a diameter of 0.5 mm. A temperature sensor to determine the temperature of the sensor housing is located to the left of the absorber.


tnt22

ЦитироватьMASCOT Lander‏Подлинная учетная запись @MASCOT2018 5 ч. назад

Guidance, navigation and control sensors https://www.dlr.de/irs/en/desktopdefault.aspx/tabid-11349 ...
#asteroidlanding #hayabusa2

https://www.dlr.de/irs/en/desktopdefault.aspx/tabid-11349
ЦитироватьMASCOT: Attitude Determination System

Спойлер
The Mobile Asteroid Surface Scout (MASCOT) is a small landing package build by the German Aerospace Center (DLR) jointly with the French National Center for Space Studies (CNES). MASCOT is flying aboard the Japanese space probe Hayabusa-II, built by the Japan Aerospace Exploration Agency (JAXA). The probe has been launched on December 3rd, 2014 for a five year sample return mission to the Near-Earth Asteroid Ryugu (1999 JU3). The lander is equipped with four science instruments which will take detailed close-up pictures and make a variety of in-situ measurements. MASCOT has a cubic shape, roughly 29 x 27.5 x 20 cm, and weighs about 10 kg. An internal mechanism with an eccentric tappet can be used to reorient MASCOT if needed and relocate to a different site to change and increase its investigation area.


Test der Lagebestimmung mit dem MASCOT-Referenzmodell

After arrival and characterization of the asteroid, MASCOT will be dropped from the Hayabusa-II mothership and will land passively on the asteroid surface. Before starting science measurements, MASCOT must lie on the correct side.


MASCOT-Trajektorien und Sensor-Simulation
[свернуть]
The attitude determination system consists of two types of sensors: solar cell-based Sun sensors on each side of MASCOT as well as five optical proximity sensors (OPS). The latter consists of a LED and a photodiode which can detect the reflected LED light when MASCOT is in proximity to the surface.

A histogram filter is used for attitude determination and multi-sensor data fusion. It is a Bayesian filter used to estimate states which can be divided in a finite number of possible values. This is useful for MASCOT, since all that is needed is an estimation of the side on which it is lying.

The GNC systems department is responsible for this attitude determination system. This includes concept design, sensor selection and procurement, algorithm development, simulation, software requirements, testing on software level as well as Hardware-in- the-Loop and mission support.

tnt22

ЦитироватьMASCOT Lander‏Подлинная учетная запись @MASCOT2018 5 ч. назад

Swing arm ... to be able to move on #Ryugu https://www.dlr.de/blogs/en/all-blog-posts/Moving-around-on-an-unfamiliar-celestial-body.aspx ...
#asteroidlanding #hayabusa2

https://www.dlr.de/blogs/en/all-blog-posts/Moving-around-on-an-unfamiliar-celestial-body.aspx
Цитировать24. September 2018 | posted by Friederike Wolff
Moving around on an unfamiliar celestial body


Credit: DLR (CC-BY 3.0)

MASCOT's swing arm

Mov­ing around on small bod­ies is dif­fi­cult, be­cause the grav­i­ta­tional pull and thus the fric­tion be­tween a lan­der and the ground is very small. Con­ven­tional means of trans­port, such as wheels or chains, are based on trac­tion and are thus un­suit­able for use on as­ter­oids. There­fore, a mo­bil­ity mech­a­nism was de­vel­oped for MAS­COT in order to en­able move­ment in such an en­vi­ron­ment: the lan­der is equipped with a swing arm that ac­cel­er­ates and de­cel­er­ates an ec­cen­tri­cally mounted mass. The re­sult­ing re­ac­tion forces, in turn, allow the lan­der to push it­self away from the ground. As the grav­i­ta­tional pull is very low, even small push-off forces can re­sult in big jumps: a dis­tance of 17 me­tres can be achieved with an ini­tial speed of only five cen­time­tres per sec­ond. The grav­i­ta­tional ac­cel­er­a­tion on the sur­face of Ryugu is only 0.00015 me­tres per sec­ond squared and is thus 60.000 times lower than on Earth (9.81 m/s2).

Test­ing out this mech­a­nism on Earth, how­ever, proved very dif­fi­cult, as the tra­di­tional meth­ods for test­ing in mi­cro­grav­ity con­di­tions could not be put to any mean­ing­ful use. On par­a­bolic flights, the grav­ity is zero on av­er­age, but there is also high-fre­quency ac­cel­er­a­tion, which, al­though low, nev­er­the­less dom­i­nates any move­ment caused by the mo­bil­ity. In ad­di­tion, the ac­cel­er­a­tion on the MAS­COT lan­der should not be brought down to zero, but must be pre­cisely re­duced to a very low value to mimic the con­di­tions on Ryugu. For two-di­men­sional prob­lems, it is com­mon to use a pneu­matic table for test­ing, which is based on the same prin­ci­ple as air hockey. Bod­ies can move freely across the plane of the table and ro­tate around the ver­ti­cal axis. Gen­tly tilt­ing the table also in­tro­duces a slight force of grav­ity. How­ever, the mech­a­nism is de­signed to make MAS­COT ro­tate around all three axes: as the ac­cel­er­ated mass is ec­cen­tri­cally mounted, it cre­ates torques around all of the axes in ad­di­tion to the ro­tat­ing cen­trifu­gal force in the plane of the arm. The re­sult is that, with every mo­tion, MAS­COT is mov­ing and ro­tat­ing in three di­rec­tions, while at the same time shift­ing its cen­tre of grav­ity. This also makes coun­ter­bal­anc­ing the weight force with a he­lium bal­loon dif­fi­cult in tests con­ducted on Earth.
Спойлер

Credit: DLR (CC-BY 3.0)

Pre­dict­ing the lan­der's move­ments on the as­ter­oid thus means re­sort­ing to nu­mer­i­cal mod­els and sim­u­la­tions. There are nu­mer­ous mod­els for sim­u­lat­ing con­tact forces be­tween bod­ies. Sim­u­lat­ing the ef­fect of the mo­bil­ity mech­a­nism means de­ter­min­ing how MAS­COT's geom­e­try in­ter­sects with that of the ground at every point in time, and using the depth of the pen­e­tra­tion to cal­cu­late a con­tact force based on a mass-spring-damper model. It is nev­er­the­less dif­fi­cult to es­tab­lish pa­ra­me­ters re­quired by these mod­els such as stiff­ness or the damp­ing of the ground, as no data is avail­able re­lat­ing to the con­di­tions on as­ter­oids like Ryugu. Un­for­tu­nately, pre­cise move­ment in mi­cro­grav­ity is heav­ily de­pen­dent on such pa­ra­me­ters, while the lan­der's mo­bil­ity mech­a­nism must be able to cope with both bare rock and porous, peb­ble-cov­ered sur­faces.
 
The prob­lems faced by MAS­COT were solved by cal­cu­lat­ing dif­fer­ent mo­tion pro­files op­ti­mised for three dif­fer­ent types of ground sur­face. The Au­ton­omy Man­ager tests out each of these in suc­ces­sion by per­form­ing a ma­noeu­vre. If a mo­tion pro­file does not lead to the right out­come, an ac­tion suit­able for a dif­fer­ent type of ground sur­face is car­ried out. After each ma­noeu­vre, dis­tance sen­sors on the sides of the lan­der are used to check which side faces the ground. LEDs and pho­to­di­odes that mea­sure the light re­flected by the sur­round­ing ter­rain are mounted on all sides. The stronger the mea­sured sig­nal, the closer the sen­sor is to an ob­sta­cle or the ground. In ad­di­tion, MAS­COT has pho­to­cells that mea­sure the sun­light and fur­ther im­prove the at­ti­tude es­ti­ma­tion. These data can also be used to eval­u­ate the per­for­mance of the mo­bil­ity. Also, pic­tures are taken be­fore and after each ma­noeu­vre, which can also be used to de­duce the move­ment.


Credit: DLR (CC-BY 3.0)

Nev­er­the­less, con­trolled re­lo­ca­tion and up­right­ing of a lan­der on a small body re­mains a chal­lenge. When re­search­ing com­pletely un­fa­mil­iar bod­ies, such as the as­ter­oid Ryugu, it is very dif­fi­cult to cre­ate a ro­bust mech­a­nism that can cope with the whole spec­trum of po­ten­tial en­vi­ron­men­tal con­di­tions. When MAS­COT sep­a­rates from the space probe Hayabusa2 on 3 Oc­to­ber, falls onto the as­ter­oid and be­gins work­ing there au­tonomously using its four sci­en­tific in­stru­ments, we will fi­nally know how it ac­tu­ally moves across the as­ter­oid's sur­face.
[свернуть]

tnt22

http://www.hayabusa2.jaxa.jp/en/news/status/
ЦитироватьOct. 01, 2018

★ Hayabusa2 status (the week of 2018.09.24) ★

This week, the MINERVA-II1 rovers that landed on the asteroid last week sent images from the asteroid surface. No regolith was seen in these images, only a shocking scenery of large and small boulders. On the other hand, the scenes of sunlight on the asteroid and the rover hopping were both very beautiful and dynamic. Next week is the deployment of the MASCOT lander. The decent operation is always a nervous time and we want to deliver the lander steadily and carefully. (Regolith: fine grain sediments).

2018.10.01 S.N.

tnt22

3 октября 2018 г. JAXA проведёт пресс-брифинг, посвящённый высадке аппарата MASCOT с зонда Сокол-2 на астероид Рюгю
Цитировать小惑星探査機「はやぶさ2」搭載小型着陸機MASCOTの分離運用に際して、記者説明会を行います。

Дата: 03.10.2018

Время: 15:00~16:00 (JST)


06:00 - 07:00 UTC 03.10.2018

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 11 ч. назад

[MASCOT] The MASCOT separation operation has begun! Preparations for the descent of Hayabusa2 towards asteroid Ryugu began in September 30, but today (October 2) the spacecraft will begin to descend.
#asteroidlanding


11 ч. назад

[MASCOT] October 2 at 12:14 JST: The spacecraft was confirmed to have started the descent from the home position (altitude of about 20km) as planned.
#AsteroidLanding


11 ч. назад

[MASCOT] October 2 at 14:40 JST: The spacecraft is descending towards Ryugu. The altitude is now about 16km.
#asteroidlanding


8 ч. назад

[MASCOT] October 2 at 17:10 JST: the altitude of Hayabusa2 is about 12 km. This photo was captured by the ONC-W1 at about 04:30 JST. Currently, Ryuyu still looks small!
#Asteroidlanding



tnt22

http://www.hayabusa2.jaxa.jp/en/topics/20181002e_MSC_schedule/
Цитировать...
MASCOT sequence


[open in another window]
Figure 2: Schematic of MASCOT operation on Ryugu.(©DLR)[/LIST]Note: Data from MASCOT will be processed and analyzed by the MASCOT team in Germany and France. The data from MASCOT will also be published by the MASCOT team.

Hayabusa2 project
2018.10.02

tnt22

ЦитироватьHAYABUSA2@JAXA‏ @haya2e_jaxa 7 ч. назад

[MASCOT] October 2 at 18:40 JST: The altitude of Hayabusa2 has passed 10km. Communications are now via the Madrid DSN station. There are more than 20 members in the Hayabusa2 control & operation rooms on the JAXA Sagamihara campus, monitoring the situation of the spacecraft.


5 ч. назад

[MASCOT] October 2 at 20:00 JST the altitude of the spacecraft has passed 8km.


5 ч. назад

[MASCOT] Currently, we communicating via an antenna of the Madrid DSN. Two antennas are currently in use for us as this is an important operation so we have secured a backup antenna. This can be seen on this website where HYB2 is Hayabusa2!
https://eyes.nasa.gov/dsn/dsn.html 


4 ч. назад

[MASCOT] October 2 at 21:30 JST: The altitude of the spacecraft has passed 6km. This photo was captured by the ONC-W1 at about 21:00 JST. Ryugu is gradually getting bigger!




3 ч. назад

[MASCOT] October 2 at 22:45 JST: Hayabusa2 has slowed its descent and is now approaching Ryugu at about 0.1 m/s. Altitude is about 4500 m and we are approaching more slowly than ever before.

tnt22


tnt22

https://spaceflightnow.com/2018/10/02/descent-begins-for-european-asteroid-lander/
ЦитироватьDescent begins for European asteroid lander
October 2, 2018 | Stephen Clark


Artist's concept of the Hayabusa 2 spacecraft approaching asteroid Ryugu. Credit: DLR

A German-built landing probe the size of a microwave oven carrying a camera and a suite of scientific instruments was closing in on asteroid Ryugu Tuesday, riding aboard Japan's Hayabusa 2 spacecraft to join two other robots deployed to the asteroid's surface last month.

The Mobile Asteroid Surface Scout, or MASCOT, is set to be released fr om the Japanese Hayabusa 2 mothership at 0158 GMT Wednesday (9:58 p.m. EDT Tuesday) for a free-fall final descent to the asteroid, with its landing velocity tempered by Ryugu's tenuous gravity field.

A few minutes later, MASCOT will reach Ryugu, and likely bounce several times before coming to a rest.

The battery-powered robot is set to land on the asteroid a week-and-a-half after a pair of Japanese landers — each one even smaller than MASCOT — touched down on Ryugu and beamed back the first-ever images fr om the surface of an asteroid.

MASCOT carries four instruments, and if it functions as designed, the lander will capture wide-angle color photos from Ryugu's craggy surface, collect measurements to determine if Ryugu's boulders emit a magnetic field, gather temperature and thermal information, and analyze the composition of the asteroid surface.
Спойлер
Launched in a carrying bay aboard Hayabusa 2 in December 2014, the MASCOT lander has been powered up and tested to ensure its instruments are ready for action. But the robot is heading into a hazardous environment on Ryugu, an asteroid that circles sun mostly between the orbits of Earth and Mars, and spans around 3,280 feet (1 kilometer) in diameter along its equator and approximately 2,880 feet (880 meters) from pole-to-pole.

The airless landing site sel ected for the European-made robot lies in Ryugu's southern hemisphere, with a temperature range between minus 81 degrees Fahrenheit (minus 63 degrees Celsius) to 145 degrees Fahrenheit (47 degrees Fahrenheit), comfortable enough for MASCOT to survive for at least 16 hours.

https://www.youtube.com/watch?v=8H4aZX_8hMA
But Hayabusa 2's reconnaissance of Ryugu since the mission's arrival at the asteroid in June has revealed a landscape strewn with boulders, introducing hurdles for hopping landers like MASCOT.

"MASCOT has to endure quite a bit on the surface," said Ralf Jaumann, principal investigator for the MASCOT lander at DLR, the German Aerospace Center. "Ryugu has very, very large boulders lying around. These will be like mountains for little MASCOT when it's on the surface. These boulders can be up to 40 meters (131 feet) tall."

Once it settles on the asteroid, MASCOT will use a mechanism to orient itself upright, then hop across Ryugu, exploring up to several different locations before its power supply runs out. MASCOT's lifetime is limited by the capacity of its battery, and it does not carry solar panels to recharge.

Scientists had to balance the needs of MASCOT's four instruments to pick a landing zone, which also had to be clear of sites wh ere Hayabusa 2 itself will attempt touch-and-go maneuvers in the coming months to collect samples for return to Earth.

"We are anxious to see whether MASCOT will slide out of its supporting frame smoothly, as we have planned and tested so extensively," said Tra-Mi Ho, MASCOT's project manager at DLR. "A smooth descent is crucial, otherwise MASCOT will bounce back up from the asteroid like a rubber ball due to the low gravitational pull, and be lost in space."

Scientists have calculated that Ryugu's gravity field is 80,000 times weaker than Earth's, making operations in the asteroid's vicinity more akin to a docking in space than a landing on a planet.

"We're entering a world that no one has ever seen before," said Christian Krause, MASCOT operations manager at DLR. "This is a single shot, everything has to work. We will simply be ejected. In principle, it desn't matter how we land on the surface."

MASCOT is a joint project between DLR and CNES, the German and French space agencies, and includes many of the same engineers and scientists who developed the larger Philae lander that flew to comet 67P/Churyumov-Gerasimenko with the European Space Agency's Rosetta spacecraft.

Philae landed on the comet in November 2014, less than a month before the launch of MASCOT, which officials have nicknamed Philae's "little brother."

MASCOT has a mass of around 22 pounds (10 kilograms) and measures 11.8 inches (30 centimeters) by 11.8 inches by 7.9 inches (20 centimeters).

"MASCOT is a small box about as big as a microwave oven," Jaumann said.

A team of controllers stationed at DLR's space center in Cologne, Germany, will monitor MASCOT during its exploration of Ryugu. They will decide whether to dispatch the lander to a different location, using a swing arm designed to generate momentum for hops in the asteroid's ultra-low gravity.

"In the final tests before the landing, we estimated that we would probably only let MASCOT perform one jump of less than 10 meters (32 feet), in order to preserve the battery life and ensure the optimal execution of the measurements and data transfer," Ho said. "What is more, recent images suggest that the surface of Ryugu has a rather uniform composition everywhere, so we do not need to perform big jumps."

In preparation for MASCOT's deployment, Hayabusa 2 started approaching asteroid Ryugu early Tuesday from a range of 12 miles (20 kilometers), heading for a position less than 200 feet (60 meters) from the asteroid, wh ere it will release the lander for its unpowered descent.


Japan's MINERVA-II Rover 1B took this picture from the surface of asteroid Ryugu on Sept. 23. Credit: JAXA

Officials from the Japan Aerospace Exploration Agency, which leads the Hayabusa 2 mission, released more pictures from a pair of mobile robots Thursday, several days after their landings on Ryugu.

The imagery reveals an uneven surface, with numerous rocks and boulders of various sizes. JAXA's update on the MINERVA-II-2 rovers last week indicated they were still functioning, with the help of solar panels to generate electricity.

Like MASCOT, the MINERVA-II-1 rovers carry internal mechanisms to hop across the asteroid, rather than wheels like the ones used on rovers driving on Mars. All of the landers communicate with Earth through the Hayabusa 2 mothership.

Ryugu is currently located 202 million miles (around 325 million kilometers) from Earth, and it takes approximately 16 minutes for a radio signal to cover the distance from Hayabusa 2 to Earth.

The low data rate link between Hayabusa 2 and MASCOT, coupled with the need to communicate with the Hayabusa 2 spacecraft itself, will mean scientists must wait a few days to receive measurements and photos fr om the lander. But controllers in Cologne, which will be linked with the Hayabusa 2 command center in Sagamihara, Japan, expect to receive confirmation Wednesday that MASCOT successfully deployed and reached the asteroid's surface.

"This is a completely different world," Jaumann said. "It's, very very far away, and we haven't seen anything like it before. When the first image comes in, and you see the surface, it could certainly look like a pile of rubble, but it is an extremely exciting pile of rubble. So I am really looking forward to seeing the first pictures."
[свернуть]