Raumfahrt - JAXA´s Asteroid Explorer Hayabusa-2 auf Kurs zu Asteroid 1999 JU3 -Update-4


Asteroid Ryugu poses landing risks for Japanese mission

Mission planners have chosen the first landing sites on boulder-strewn body for Hayabusa2 and its rovers to touch down.

The landing site for Hayabusa’s MASCOT lander is shown in blue on the asteroid Ryugu.Credit: JAXA

After inspecting asteroid Ryugu for two months, the Japan Aerospace Exploration Agency (JAXA) has revealed the sites where the Hayabusa2 spacecraft will touchdown to collect a sample to bring back to Earth — and also where it will drop the first two of its planned landing probes.

Mission planners faced tough choices because the body almost uniformly strewn with boulders. “Ryugu is beautiful, but challenging,” said Aurélie Moussi, a collaborator from the French space agency CNES in Toulouse, at a press conference in Sagamihara, Japan, on 23 August.

Hayabusa2 is the follow-up mission to Hayabusa, a probe that was the first to collect samples from an asteroid and bring them back to Earth in 2010. The latest mission reached Ryugu in June, after three and a half years of travel from Earth.

Since then, Hayabusa2 has been hovering a few tens of kilometres above the space rock and scanning its surface as it revolves every seven-and-a-half hours. The spacecraft also made a closer approach earlier this month, temporarily letting itself fall down to an altitude 851 metres. By measuring the speed of that free fall, mission control was able to estimate the mass of the asteroid, at about 450 million tonnes.

Three landers

Hayabusa2 carries three landers that it will eject to the asteroid over its mission. It will also touch down itself to collect samples to return to Earth. In today’s press conference, members of the mission team described how they picked the sites for the first of two touchdowns and for releasing MASCOT — a lander built by the French and German space agencies — and the first of the two MINERVA-II landers, built by a Japanese consortium.

In early October, Hayabusa will temporarily fly down to an altitude of 60 metres to drop MASCOT. The operation will involve some risk: the shoebox-sized lander does not have the ability to steer itself, and mission control can predict where it will hit the ground only within a region around 70 metres wide. After that first impact — at a leisurely speed of around 30 centimetres per second — MASCOT will bounce in an unpredictable direction, and its final arrival place is even more uncertain, by hundreds of metres.

“Until we land, we don’t know how it looks on the landing site,” TraMi Ho of German space agency DLR said at the press conference.

To minimize risks for MASCOT, mission planners mapped the topography of Ryugu and the distribution and size of the boulders on its surface. They ran computer simulations to produce a shortlist of ten options, and then picked one spot on the asteroid’s southern hemisphere. The choice reflected a number of criteria, including average temperatures on the ground and the materials that MASCOT will analyse with its four on-board instruments. “The other sites would have been just as good, or just as difficult,” says MASCOT payload manager Stephan Ulamec of the German Aerospace Center in Cologne. “Wherever we look, there is a lot of big boulders.”

Itokawa, the potato-shaped asteroid visited by the first Hayabusa, had a more diverse surface, Ulamec says, and the mission team team was able to choose a lower-risk landing site in a sandy area, which they named the Muses Sea.

Hayabusa2 will make its first touchdown, planned for late October, at a site just north of the equator. The first of two MINERVA II probes will land in late September.

Quelle: nature


Landing Site on Asteroid Ryugu Chosen for Japan's Hayabusa2 Mission


The MA-9 site on the asteroid Ryugu, where the Hayabusa2 spacecraft's MASCOT lander will touch down on Oct. 3, 2018.


We now know where a Japanese asteroid-sampling probe's lander will touch down this October.

The Hayabusa2 spacecraft's Mobile Asteroid Surface Scout (MASCOT) will land at a site in the asteroid Ryugu's southern hemisphere dubbed MA-9, mission officials announced today (Aug. 23). 

MA-9 won out over nine other finalists because it offered the best combination of scientific potential and accessibility, MASCOT team members said.


MA-9 and a few other landing site targets on the asteroid Ryugu.

"From our perspective, the selected landing site means that we engineers can guide MASCOT to the asteroid's surface in the safest way possible, while the scientists can use their various instruments in the best possible way," MASCOT project manager Tra-Mi Ho, of the DLR Institute of Space Systems, said in a statement. (DLR is the German Aerospace Center, which operates MASCOT with support from the French space agency, CNES.) 

MA-9 features relatively fresh, pristine surface material that hasn't been exposed to cosmic radiation for long compared to other parts of the 3,000-foot-wide (950 meters) asteroid, team members said. And Hayabusa2 will drop three small rovers onto patches of the space rock's northern hemisphere, so a southern site for the 22-lb. (10 kilograms) MASCOT will give the mission greater coverage of the space rock, they added.  

In addition, MA-9 isn't quite as boulder-studded as most other Ryugu regions. That doesn't mean landing there will be a breeze on Oct. 3, however.


A close-up look at the sites L07, L08 and M04 on the asteroid Ryugu.

"But we are also aware: There seem to be large boulders across most of Ryugu's surface and barely [any] surfaces with flat regolith," Ho added. "Although scientifically very interesting, this is also a challenge for a small lander and for sampling."

The $150 million Hayabusa2 mission launched in December 2014 and arrived at Ryugu on June 27 of this year. If all goes according to plan, the spacecraft will study the big asteroid from orbit for another 16 months and also drop down several times to grab samples of Ryugu material. 

Meanwhile, MASCOT and the three tiny, hopping rovers — known as Minerva-II-1a, Minerva-II-1b and Minerva-II-2 — will gather a variety of information about the asteroid from its surface. (Minerva-I flew aboard Japan's first asteroid-sampling mission, the original Hayabusa, which returned grains from the space rock Itokawa to Earth in 2010.)

The Hayabusa2 orbiter is scheduled to depart from Ryugu in December 2019. The capsule containing the mission's asteroid samples will come down to Earth a year later, in December 2020. 

Hayabusa2 isn't the only asteroid-sampling project underway. NASA's $800 million OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission is on its final approach toward the asteroid Bennu, and should arrive in orbit around the 1,650-foot-wide (500 m) rock this December. OSIRIS-REx's samples are due to land on Earth in September 2023.

Both Hayabusa2 and OSIRIS-REx aim to help scientists better understand asteroid composition and structure, the early history and evolution of the solar system, and the role space rocks may have played in helping life get a start on Earth. 

Bringing pristine samples of asteroid material back to Earth will allow researchers to tackle such questions efficiently and effectively, team members from both missions have said. Scientists can perform many more experiments and investigations using well-equipped labs around the world than a robotic probe could conduct all by itself in deep space.

Quelle: SC


Update: 6.09.2018


Boulders on the surface of asteroid Ryugu

Images from Hayabusa2 revealed many more boulders on the surface of asteroid Ryugu than were expected. Asteroid Itokawa also has a large number of boulders, but Ryugu appears to have more per unit area. Figures 1 and 2 show boulders marked in green that appear to be between 8 m to more than 10 m in size, based on images taken from the home position (about 20 km away from Ryugu) on June 30, 2018.


  • Figure 1: Distribution of boulders on the surface of Ryugu (asteroid is pictured at 300 degrees longitude). A green marker indicates a boulder that appears to be between 8 m to 10 m or more. In this figure the north pole of the asteroid is at the image top.
    Image credit ※: Kindai University, JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University. University of Aizu, AIST.

Figure 1 shows a region of Ryugu’s surface where the boulder coverage is comparatively low. By contrast, Figure 2 shows a region where there seems to be far more boulders (although it is possible that this will change with more detailed analysis in the future). Both regions in Figure 1 and Figure 2 have hundreds of identified boulders, but there is also considerable variation between places where the boulder number is particularly high and regions where there are fewer. In general, boulders provide valuable evidence about the kinds of collision that an asteroid has been subjected to over its lifetime. The number, shape and variation of these boulders will therefore be examined in detail and, when compared with other observational data, allow the formation of asteroid Ryugu to be revealed.


  • Figure 2: Distribution of boulders on the surface of Ryugu (asteroid is pictured at 60 degrees longitude). A green marker indicates a boulder that appears to be between 8 m to 10 m or more. In this figure the north pole of the asteroid is at the image top.
    Image credit ※: Kindai University, JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST.

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


Tatsuhiro Michikami (Faculty of Engineering, Kindai University), Hayabusa2 ONC Team.

Quelle: JAXA


Is That the Death Star? Japanese Probe's Pictures of Ryugu Show a Divot on Top


A view of the asteroid Ryugu taken by the Hayabusa2 spacecraft's laser altimeter after a month of measurement.

Credit: National Astronomical Observatory, JAXA, Chiba Institute of Technology, Aizu Univ., Nippon Univ., Osaka Univ.


That's no moon — it's an asteroid. New pictures of Ryugu, the target asteroid for Japan's Hayabusa2 landing mission, looks a bit like the infamous world-destroying "Death Star" spacecraft of "Star Wars" yore. And that's just one view of Ryugu recently sent to Earth by the probe.

Hayabusa2 is still measuring Ryugu's shape, but preliminary data from the probe's laser altimeter instrument shows that the spacecraft looks like a spinning top. However, there's a large divot at the top of the asteroid, which is reminiscent of the small hole on one hemisphere of the Death Star.

The difficulty with measuring Ryugu is it's very hard to track the orbit of the spacecraft, the Japan Aerospace Exploration Agency (JAXA) said in a statement translated to English using Google Translate.

Generally, scientists can map the shape of a world by tracking changes in the trajectory of an orbiting spacecraft, which is pulled "down" toward the asteroid in places of higher mass. But this is a difficult measurement to do with Ryugu, which is very small (roughly 3,000 feet across, or 900 meters).

While scientists refine Hayabusa2's trajectory, they're also picking up information on the surface to help prepare the spacecraft for several "touch-and-go" procedures to pick up soil and return it to Earth. Hayabusa2 will also deploy several landers and rovers to explore the surface — the first of those will approach the planet on Sept. 21 and Oct. 3.

From pictures taken 12 miles (20 kilometers) above Ryugu's surface, Hayabusa2 recently mapped out hundreds of rock masses that each have a diameter of between 26 feet and 33 feet (8 and 10 m).

"It turned out that there are more rock masses on the surface of the asteroid Ryugu than expected," JAXA officials said. Ryugu has more rocks in a given area than asteroid Itokawa, which was the target of the predecessor Hayabusa mission that concluded in 2010. Scientists are studying the masses closely to learn more about how Ryugu was formed, JAXA added.

Another piece of the formation process comes through understanding what minerals are on the surface of Ryugu. A preliminary map shows temperature differences on the asteroid taken with Hayabusa2's infrared camera. Already, scientists can see a marked temperature difference between the northern and southern hemispheres of Ryugu, although the reason is still under investigation. 

So far, scientists say the highest-temperature areas appear to be around 212 degrees Fahrenheit (100 degrees Celsius), while the lowest-temperature areas appear to be room temperature. While JAXA did not define what "room temperature" means, generally that indicates temperatures of about 68 to 77 degrees F (20 to 25 degrees C).

Hayabusa2 arrived at Ryugu on June 27 and is expected to make its first touch-and-go landing in October.

Quelle: SC


Update: 11.09.2018


Thermography of Ryugu by the TIR

We conducted observations of asteroid Ryugu using the Thermal Infrared Imager (TIR) onboard Hayabusa2. Figure 1 shows the thermographic image taken using the TIR at an altitude of 20 km (the home position) from Ryugu.

  • tir-thermography-20180630
  • Figure 1: Asteroid Ryugu observed with the Thermal Infrared Imager (TIR). The images were captured between 16:02 – 23:45 JST on June 30, 2018 and were taken every eight minutes for one rotation. From the 20 km altitude (home position), one pixel is about 20 m in size. The distance to the Sun at this time is 0.987 au (1 au is about 1.496 billion km, the average annular distance between the Sun and the Earth). The scale bar shows relative temperature (the values have no meaning). Red indicates a high temperature while blue is for colder temperatures.
    Image credit ※: JAXA, Ashikaga University, Rikkyo University, Chiba Institute of Technology, University of Aizu, Hokkaido University of Education, Hokkaido Kitami Hokuto High School, AIST, National Institute for Environmental Studies, University of Tokyo, German Aerospace Center (DLR), Max Planck Society for the Advancement of Science, Stirling University.

The image shows the temperature differences on Ryugu's surface during one rotation, with red indicating regions with a high temperature. Distinct regions at different temperatures are captured by the TIR. Features in a thermal image can be seen even if they are in a shaded location in the visible photograph. This lets us confirm that the overall shape of the asteroid is well understood, and also the characteristic topography such as craters and large boulders that show up as a difference in temperature.

A temperature difference can also be seen between the north and south hemispheres of the asteroid. At present, it is summer in the southern hemisphere (the upper part of the figure) and the temperature is higher in this region. In the northern hemisphere in the lower part of the figure, it is currently winter and colder. This difference is due to the inclination of the rotation axis, which results in different levels of radiation reaching the north and south. The TIR has therefore spotted that asteroids also undergo a “seasonal change”.

High temperatures on the asteroid reach 100°C, while the coldest regions sit at about room temperature. Temperatures also change depending on the solar distance of the asteroid, lowering as Ryugu moves further away from the Sun.

During the Hayabusa2 mission, we will investigate the formation process of asteroids by examining the characteristics of the surface material revealed by differences in surface temperature. From the TIR data, we can also look for scientifically important landing sites with millimeter-sized grains, and avoid landing Hayabusa2 in severe temperature environments or locations with obstacles such as boulders.

Reference: An article by Takehiko Arai, member of the TIR team, was posted on the Ashikaga University website (Japanese only).

Quelle: JAXA, Ashikaga University & collaborators


Navigation Images from
the Rehearsal 1 for Touchdown 1
(Real time delivery)

Navigation images of the Rehearsal 1 for Touchdown 1 (Sep. 11 - Sep. 12, 2018), taken by the wide-angle camera ONC-W1.

We are currently delivering navigation images with the Optical Navigation Camera Wide angle (ONC-W1) in real time. Please understand that the image may be distorted due to the network status or data processing.

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  • Received time: UTC 2018-09-11 19:48

Quelle: JAXA


Update: 13.09.2018


[TD1-R1] Last navigation image (ground receiving time: UTC 2018-09-12 03:58) taken when the distance to Ryugu’s surface was ~635m. The image top is Ryugu's south pole, the bright side on the left is due to the opposition effect & within it is the black dot shadow of Hayabusa2!


Quelle: JAXA


My folks at Lander Control Center in , Germany are getting ready for my on 3 October 2018. 


MASCOT auf Hayabusa2

Die japanische Raumsonde Hayabusa2 befindet sich seit dem 3. Dezember 2014 auf einer Probenrückführmission zum Asteroiden (162173) Ryugu (ehemals 1999 JU3). Mit an Bord ist der Lander MASCOT. Er wurde federführend vom Deutschen Zentrum für Luft- und Raumfahrt (DLR) in enger Zusammenarbeit mit der französischen Raumfahrtagentur CNES und der japanischen Raumfahrtagentur JAXA gebaut. Ziel von Hayabusa2 ist es, mehr über den Ursprung und die Entwicklung unseres Sonnensystems zu erfahren. Asteroiden gehören zu den ursprünglichsten Himmelskörpern. Ihre Erforschung ermöglicht uns einen Blick zurück in unsere kosmische Vergangenheit. Aber nicht nur das: Ryugu gehört zu einer häufig vorkommenden Klasse von erdnahen Asteroiden. Diese stellen eine potentielle Bedrohung für die Menschheit dar, die es zu untersuchen und zu reduzieren gilt.

MASCOT Lander auf Twitter


Quelle: DLR


MASCOT: Asteroidenlander mit Orientierungssinn


Seit dem 3. Dezember 2014 ist der Asteroidenlander MASCOT (‚Mobile Asteroid Surface Scout‘)auf dem Weg zum Erdnahen Asteroiden (162173) Ryugu (1999 JU3). An Bord der japanischen Hayabusa2-Sonde wird er 2018 sein Ziel erreichen. Dort soll die Hayabusa2-Sonde im dichten Flug über dem Asteroiden Material von seiner Oberfläche "einsaugen" und zur Erde zurückbringen. MASCOT hingegen wird aus einer Höhe von 100 Metern im freien Fall auf den einen Kilometer Durchmesser großen Asteroid aufsetzen, sich hüpfend fortbewegen und erstmals in der Raumfahrtgeschichte an mehreren Orten Messungen auf einem Asteroiden durchführen.

Vier Instrumente im Einsatz

2019 werden die Asteroidenforscher insgesamt bis zu 16 Stunden lang Daten erhalten, die sie so bisher noch nie messen konnten. Ist die Batterie (ein Beitrag der französische Raumfahrtagentur CNES) des Landers nach zwei Asteroidentagen und -nächten erschöpft, endet auch seine Mission. MASCOT hat keine Solarpaneele zum Aufladen.

Eine Rahmenbedingung des japanischen Hayabusa2 Teams war das Gewicht des Landers: Gerade einmal zehn Kilogramm durfte MASCOT wiegen. . Insgesamt vier Instrumente brachten die Ingenieure des DLR in einer sehr stabilen und zugleich leichten Struktur unter. Mit einem Radiometer und einer Kamera des DLR, sowie einem Spektrometer des Institut d’Astrophysique Spatiale und einem Magnetometer der TU Braunschweig sollen die mineralogische und geologische Zusammensetzung der Asteroidenoberfläche untersucht und Oberflächentemperatur sowie Magnetfeld des Asteroiden ermittelt werden.

Bis zu 70 Meter weite Sprünge auf dem Asteroiden

Mit Sensoren wird das kleine, schuhkartongroße Landepaket sich orientieren und feststellen, ob es auf seiner Ober- oder Unterseite gelandet ist. Dann kann der Lander mit einem Schwungarm im Inneren gegebenenfalls in die richtige Position "hüpfen", sich so ausrichten und mit Messungen beginnen. Sind alle vier Instrumente zum Einsatz gekommen, aktiviert MASCOT automatisch erneut den Schwungarm und springt bis zu 70 Meter weit zu seinem nächsten Einsatzort. Mit an Bord hat er neben den Instrumenten ein Thermalsystem, um die Temperaturen auf dem Asteroiden auszugleichen, und einen Bordcomputer, der die gewonnenen Daten über die Muttersonde Hayabusa2 ins DLR-Kontrollzentrum sendet.

Warum Asteroidenforschung?

Asteroiden gehören, wie Kometen, zu den kleinen Körpern im Sonnensystem. Sie gelten nicht nur als Überbleibsel der frühen Phase der Planetenentstehung, sondern sollen auch der Ursprung für das Wasser auf der Erde sein: Schwere Bombardierungen der jungen Erde durch Asteroiden sollen  vor ca. 3,8 Milliarden Jahren Wasser und komplexe Moleküle auf unseren Planeten gebracht haben. Dies soll der Schlüsselprozess für die Entstehung von Leben sein.

Asteroiden werden durch ihre Umlaufbahnen (zum Beispiel Hauptgürtel-Asteroiden, Trojaner, Erdnahe Asteroiden) und durch Merkmale in ihrem Reflektionsspektrum (‚Asteroiden Taxonomie‘) unterschieden.

Ryugu (1999 JU3) gehört zu einer Klasse von sehr häufig vorkommenden erdnahen Asteroiden. Dieser Asteroiden-Typ ist von besonderem Interesse, da ihr Spektrum denen der kohlenstoffhaltige Chondrite  ähneln und derer chemische Zusammensetzung sehr nahe dem unserer Sonne und des frühen Sonnennebels sind. Zusätzliche wurde auf diesen Typwasserhaltige Minerale gefunden.  Antworten zu der Lebensmaterie, dem Ursprung und der Evolution unseres Sonnensystems zu finden ist daher das Hauptziel von MASCOT als wissenschaftliche Nutzlast der Hayabusa2 Mission.

Forschung vor Ort und im Labor

Bereits die erste Hayabusa-Mission der japanischen Raumfahrtagentur JAXA war ein Erfolg: 2010 brachte die japanische Hayabusa-Sonde in einer Kapsel zum ersten Mal Asteroidenmaterial in seiner ursprünglichen, unveränderten Form zur Erde. Damals untersuchte auch das DLR-Institut für Planetenforschung die seltenen Partikel. Mit der Hayabusa2-Mission soll nun erneut Material zur Erde gebracht werden, aber auch mit MASCOT direkt vor Ort gemessen werden. "Unsere Daten werden unter anderem auch als Referenz für die Untersuchungen in den irdischen Laboren dienen", sagt DLR-Projektleiterin Dr. Tra-Mi Ho. Außerdem wird der Lander als Späher erkunden, wo die japanische Sonde das Asteroidenmaterial einsammeln soll. "Sonde und Lander werden unser Wissen über Asteroiden auf jeden Fall vervielfachen."

Die DLR-Beteiligung an der Hayabusa2-Mission

Das DLR-Institut für Raumfahrtsysteme entwickelte den Lander und testete ihn unter Weltraumbedingungen bei Parabelflügen, im Bremer Fallturm (ZARM) und auf dem Schütteltisch sowie in der Thermalvakuum-Kammer bei sich im Institut. Das DLR-Institut für Faserverbundleichtbau und Adaptronik war für die stabile Struktur des Landers zuständig. Das DLR Robotik und Mechatronik Zentrum entwickelte den Schwungarm, den MASCOT auf dem Asteroiden hüpfen lässt. Das DLR-Institut für Planetenforschung steuerte die Kamera MASCAM und das Radiometer MARA bei. Überwacht und betrieben wird Asteroidenlander MASCOT aus dem DLR-Kontrollzentrum des Nutzerzentrums für Weltraumexperimente (MUSC) in Köln. Das CNES hat zu MASCOT das Power-Subsystem beigetragen, einen Teil des Telekommunikationssystems einschließlich Antennenentwicklung, die Abstiegs- und Landemissionsanalyse. Messungen der Magnetisierung des Asteroiden konnten anhand des an der TU Braunschweig entwickelten Magnetometer MasMag durchgeführt werden.

Quelle: DLR


Update; 20.09.2018


[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)


[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.


[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.


[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.


[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: [Image credit: JAXA]




Quelle: JAXA


Update: 19.30


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Quelle: JAXA





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