Ryugu – An asteroid with edges, ridges and big boulders

25 July 2018

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  • Dicht am Asteroiden Ryugu
    Close to the asteroid Ryugu

    On 20 July 2018, the Optical Navigation Camera - Telescopic (ONC-T) of the Japanese Hayabusa2 probe acquired an image of the asteroid Ryugu from a distance of six kilometres. The numerous large boulders on the asteroid’s surface as well as the large crater in the middle of the picture are easily recognisable. One pixel is about 60 centimetres.

  • Ryugu %2d ein "Diamant" im All
    Ryugu - a ‘diamond’ in space

    From the first images of Ryugu taken by the ONC-T of the Japanese Hayabusa2 probe, the Japanese space agency JAXA and scientists from the University of Aizu created a 3D model of the asteroid. In October 2018, the MASCOT lander, which was developed and built by the German Aerospace Center (DLR) in close cooperation with the French space agency CNES (Centre National d'Etudes Spatiales), is to land on the asteroid. The celestial body will then be explored using four instruments.

  • Asteroid Ryugu was imaged for the first time from a distance of just six kilometres
  • Among other things, the images serve as preparation for the landing site selection. The MASCOT lander, which was developed and built at DLR, is due to land on the asteroid in October.
  • Focus: Space, Exploration

As the Japanese Hayabusa2 spacecraft closes in on asteroid Ryugu, more details become visible to the planetary scientists. On 20 July 2018, from a distance of just six kilometres, the spacecraft’s Optical Navigation Camera - Telescopic (ONC-T) acquired an image of the asteroid’s surface, with its largest crater. "We see that the entire surface of Ryugu is strewn with large boulders – we have not yet seen this on an asteroid," says Ralf Jaumann, a planetary scientist at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and Principal Investigator for the MASCOT (Mobile Asteroid Surface Scout) lander aboard the Japanese spacecraft. It is anticipated that on 3 October 2018, MASCOT will land on Ryugu and examine the asteroid surface using four instruments.

Descending towards the asteroid

Since Hayabusa2’s arrival at the asteroid on 27 June 2018, the Japanese Aerospace Exploration Agency (JAXA) had operated it at a height of 20 kilometres (the Home Position) above the surface. But on 16 July, the JAXA engineers slowly lowered Hayabusa2 from this observation position, until it was six kilometres above Ryugu. The resolution of the images is approximately 3.4 times greater than in the pictures acquired from the Home Position – one pixel now corresponds to about 60 centimetres. A particularly large crater is visible near the centre of the image.

For Jaumann, the images coming from some 300 million kilometers away give the opportunity to get a first impression of the asteroid: "It is likely that Ryugu is a fragment of an earlier collision. However, we have only just been at the asteroid for a short while – and all we can see is the surface.” How old is the asteroid? What is its interior like? How dense is it? Is it made up of several agglomerated pieces of debris or is it just one large piece? These are all questions that the planetary scientists want to discuss and answer.

Preparations for the landing

On 25 July 2018, the Hayabusa2 probe returned to its previous position 20 kilometers from Ryugu. In August 2018, the probe will then be lowered again to a distance of approximately one kilometre from the asteroid’s surface to measure its gravitational field, which is estimated to be just 1/60,000th of Earth's. The detailed photographs of the 900-metre-diameter Ryugu and the determination of its gravitational field are also important for the selection of MASCOT’s landing site. At the end of August, the site will be determined by all involved international scientists and engineers. During the mission, Hayabusa2 will also descend to the asteroid’s surface several times and collect soil samples. At the end of 2019, the Japanese probe will begin its return journey to Earth, where it is expected to arrive in 2020 with the asteroid samples.

About the Hayabusa2 mission and MASCOT

Hayabusa2 is a Japanese space agency (Japan Aerospace Exploration Agency; JAXA) mission to the near-Earth asteroid Ryugu. The German-French lander MASCOT on board Hayabusa2 was developed by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and built in close cooperation with the  French space agency CNES (Centre National d'Etudes Spatiales). DLR, the Institut d'Astrophysique Spatiale and the Technical University of Braunschweig have contributed the scientific experiments on board MASCOT. The MASCOT lander and its experiments are operated and controlled by DLR with support from CNES and in constant interaction with the Hayabusa2 team. 

DLR Institute of Space Systems in Bremen was responsible for developing and testing the lander together with CNES. The DLR Institute of Composite Structures and Adaptive Systems in Braunschweig was responsible for the stable structure of the lander. The DLR Robotics and Mechatronics Center in Oberpfaffenhofen developed the swing arm that allows MASCOT to hop on the asteroid. Das DLR Institute of Planetary Research in Berlin contributed the MasCam camera and the MARA radiometer. The asteroid lander is monitored and operated from the MASCOT Control Center in the Microgravity User Support Center (MUSC) at the DLR site in Cologne.

Last modified:
10/08/2018 10:26:30



Andreas Schütz
German Aerospace Center (DLR)

Head of Media Relations department, DLR spokesperson

Tel.: +49 2203 601-2474

Fax: +49 2203 601-3249
Manuela Braun
German Aerospace Center (DLR)

Media Relations, Space Research

Tel.: +49 2203 601-3882

Fax: +49 2203 601-3249
Prof.Dr. Ralf Jaumann
German Aerospace Center (DLR)

Institute of Planetary Research, Planetary Geology

Tel.: +49 30 67055-400

Fax: +49 30 67055-402