5. October 2018

Three hops in three as­ter­oid days – MAS­COT suc­cess­ful­ly com­pletes the ex­plo­ration of the sur­face of as­ter­oid Ryugu

Ralf Jaumann gives a presentation at MASCOT Control Centre
MAS­COT worked longer and de­liv­ered more da­ta than ex­pect­ed
Image 1/3, Credit: DLR.

MASCOT worked longer and delivered more data than expected

From the evening of 2 Oc­to­ber 2018, 24 hours of ab­so­lute ten­sion pre­vailed in the MAS­COT Con­trol Cen­tre at the DLR site in Cologne: Ap­prox­i­mate­ly 40 sci­en­tists fol­lowed the events tak­ing place 300 mil­lion kilo­me­tres from Earth – even be­fore the ap­plause-filled sep­a­ra­tion of the Ger­man-French land­ing mod­ule on 3 Oc­to­ber 2018 at 03:58 CEST [please check!] from the Japanese space probe Hayabusa2, the land­ing on the as­ter­oid Ryugu six min­utes lat­er, and the end of the mis­sion at 21.04 hours CEST.MAS­COT ful­filled and ex­ceed­ed the ex­pec­ta­tions of the lan­der, as the bat­ter­ies de­liv­ered more pow­er than planned. Last­ing 17 hours, this made it pos­si­ble to con­duct ex­per­i­ments for one ad­di­tion­al hour. All four in­stru­ments on-board MAS­COT did far more than the planned mea­sure­ments and record­ings. In the fore­ground of the im­age, we can see MAS­COT Project Man­ag­er Tra-Mi Ho from the DLR In­sti­tute of Space Sys­tems in Bre­men at the MAS­COT Con­trol Cen­tre of the DLR Mi­cro­grav­i­ty Us­er Sup­port Cen­tre in Cologne, re­lieved by the al­most smooth run­ning of this ex­traor­di­nary mis­sion. In the back­ground, Ralf Jau­mann, Sci­en­tif­ic Di­rec­tor of MAS­COT, presents some of the 120 im­ages tak­en with the DLR cam­era MAS­CAM of the DLR In­sti­tute of Plan­e­tary Re­search in Berlin.
Ryugu's surface
Ryugu's sur­face – just be­fore MAS­COT's first con­tact
Image 2/3, Credit: MASCOT/DLR/JAXA.

Ryugu's surface – just before MASCOT's first contact

DLR’s MAS­CAM cam­era took 20 im­ages dur­ing MAS­COT’s 20-minute fall to Ryugu, fol­low­ing its sep­a­ra­tion from Hayabusa2, which took place at 51 me­tres above the as­ter­oid’s sur­face. This im­age shows the land­scape near the first touch­down lo­ca­tion on Ryugu from a height of about 25 to 10 me­tres. Light re­flec­tions on the frame struc­ture or the cam­era body scat­ter in­to the field of vi­sion of the MAS­CAM (bot­tom right) as a re­sult of the back­lit light of the Sun shin­ing on Ryugu.Ryugu has a coarse tex­tured, ex­treme­ly dark sur­face that re­flects on­ly about 2.5 per­cent of the in­com­ing sun­light. The rugged area shown here is about as dark as as­phalt. De­tails of the ter­rain struc­tures are vis­i­ble in the MAS­CAM im­ages thanks to the pho­to­sen­si­tive semi­con­duc­tor el­e­ments of the 1000 by 1000 pix­el CMOS (com­ple­men­tary met­al-ox­ide semi­con­duc­tor) cam­era sen­sor, whose dy­nam­ics en­hance even the weak­est light sig­nals and de­liv­er sci­en­tif­i­cal­ly us­able im­age da­ta.
The surface of Ryugus from a few metres
The sur­face of Ryu­gus from a few me­tres
Image 3/3, Credit: MASCOT/DLR/JAXA

The surface of Ryugus from a few metres

The ap­prox­i­mate­ly 20 im­ages ac­quired with the MAS­CAM cam­era on the MAS­COT lan­der dur­ing the de­scent show an ex­treme­ly rugged sur­face cov­ered with nu­mer­ous an­gu­lar rocks. Ryugu, a four-and-a-half bil­lion year-old C-type as­ter­oid has shown the sci­en­tists some­thing they had not ex­pect­ed, even though more than a dozen as­ter­oids have been ex­plored up close by space probes. On this close-up, there are no ar­eas cov­ered with dust – the re­golith that re­sults from the frag­men­ta­tion of rocks due to ex­po­sure to mi­crom­e­te­orite im­pacts and high-en­er­gy cos­mic par­ti­cles over bil­lions of years. The im­age from the tur­bu­lent ro­tat­ing MAS­COT lan­der was tak­en at a height of about 10 to 20 me­tres.
  • As planned, MASCOT was able to acquire data about the composition and texture of the asteroid at several locations.
  • Before the battery depleted, the lander sent all scientific data to the Hayabusa2 mothercraft.
  • New images from MASCOT's landing on asteroid Ryugu were presented by DLR, JAXA and CNES today at the International Astronautical Congress (IAC).
  • Focus: Space, exploration

It was a day full of exciting moments and a happy team of scientists and engineers: late in the afternoon of 3 October 2018, the German-French lander MASCOT completed its historic exploration of the surface of the asteroid Ryugu at 21:04 CEST, as its battery ran out. On-asteroid operations were originally scheduled to last 16 hours after separation from the Japanese mothercraft Hayabusa2. But in the end, the battery lasted more than 17 hours. Upon landing in the early morning and subsequently relocating using the built-in swing arm, all instruments collected detailed data on the composition and nature of the asteroid. The on-board camera provided pictures of the landing, hopping manoeuvres and various locations on the surface.

For MASCOT, the Sun set three times on Ryugu. The lander was commanded and controlled from the MASCOT Control Centre at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) in Cologne, in the presence of teams of scientists from Japan, France and Germany. All scientific data was transferred to the mother probe according to plan.

"With MASCOT, it has been possible to, for the first time, explore the surface of an asteroid directly on site so extensively," says Hansjörg Dittus, DLR Executive Board Member for Space Research and Technology. "A mission like this can only be done working in close cooperation with international partners – bringing together all their expertise and commitment." With MASCOT, DLR has been working closely with the Japanese space agency JAXA and the French space agency CNES.

Jumps and a mini-move

MASCOT landed safely on Ryugu in the early morning of 3 October 2018. "After a first automated reorientation hop, it ended up in an unfavourable position. With another manually commanded hopping manoeuvre, we were able to place MASCOT in another favourable position thanks to the very precisely controlled swing arm," says MASCOT operations manager Christian Krause from DLR. From that position, MASCOT completed a complete measurement sequence with all instruments over one asteroid day and an asteroid night. "Later, we were able to continue the activities on Ryugu with a special manoeuvre," adds Ralf Jaumann, DLR planetary scientist and scientific director of MASCOT. "With a 'mini-move' we recorded image sequences that will be used to generate stereo images of the surface once they have been analysed."

During the first manoeuvres, MASCOT moved several metres to the next measuring point. Finally, and seeing that the lander still had battery power left, the researchers dared to make a bigger jump. All in all, MASCOT explored Ryugu for three asteroid days and two asteroid nights. A day-night cycle on Ryugu lasts about 7 hours and 36 minutes. At 21:04 CEST, communications with Hayabusa2 were interrupted, because of the radio shadow entering with each asteroid rotation. Hayabusa2 is now returning to its home position, at an altitude of 20 kilometres above the asteroid’s surface.

In addition to the images acquired by the DLR camera MASCAM, a DLR radiometer, a magnetometer from TU Braunschweig and a spectrometer from the Institut d'Astrophysique Spatiale provided a variety of measurements on the temperature, magnetic properties and the composition of the near-Earth asteroid Ryugu.

Waiting for the scientific data

MASCOT is now a silent inhabitant of Ryugu. "The evaluation of the valuable data has just begun," says MASCOT project manager Tra-Mi Ho from the DLR Institute of Space Systems. "We will learn a lot about the past of the Solar System and the importance of near-Earth asteroids like Ryugu. Today, I look forward to the scientific publications that will result from MASCOT and the remarkable Hayabusa2 mission of our Japanese partners. "Hayabusa2 played a crucial role in the success of MASCOT. The Japanese probe brought the lander to the asteroid. Thanks to precise planning and control, the communication links to the lander could be optimally used for data transmission, so that the first pictures were received on the very day of landing. The remaining scientific data, which was transmitted to Hayabusa2, will be sent to Earth in the coming days.

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.

The 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.

  • Falk Dambowsky
    Ger­man Aerospace Cen­ter (DLR)

    Com­mu­ni­ca­tions and Me­dia Re­la­tions
    Telephone: +49 2203 601-3959
    Linder Höhe
    51147 Cologne
  • Tra-Mi Ho
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Space Sys­tems
    Telephone: +49 421 24420-1171
    Robert-Hooke-Straße 7
    28359 Bremen
  • Christian Krause
    Ger­man Aerospace Cen­ter (DLR)

    Mi­cro­grav­i­ty Us­er Sup­port Cen­ter (MUSC), Space Op­er­a­tions and As­tro­naut Train­ing
    Telephone: +49 2203 601-3048
    Linder Höhe
    51147 Köln
  • Manuela Braun
    Ed­i­tor HR
    Ger­man Aerospace Cen­ter (DLR)
    Cen­tral HR Mar­ket­ing
    Telephone: +49 2203 601-3882
    Münchener Straße 20
    82234 Weßling
  • Prof.Dr. Ralf Jaumann
    Freie Uni­ver­sität Berlin
    In­sti­tute of Ge­o­log­i­cal Sci­ences
    Plan­e­tary Sci­ences and Re­mote Sens­ing
    Telephone: +49-172-2355864
    Malteserstr. 74-100
    12249 Berlin

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