MAS­COT land­ing on Ryugu – op­er­a­tional se­quence

MASCOT's approach to Ryugu and its path across the surface
After MASCOT had separated from its mothercraft, Hayabusa2's ONC (Optical Navigation Camera) recording system, with its three cameras, began following MASCOT’s descent to the asteroid Ryugu from a height of 51 metres. The image section is oriented to the north, and the area shown is located at approximately 300 degrees east and 30 degrees south. Hayabusa2’s shadow can be seen on the lower right. At the time of the separation, it was about noon on Ryugu and the Sun was behind Hayabusa2 – the shadow is about six by 4.5 metres. The points indicate the times at which Hayabusa2 acquired images of MASCOT. The times are in UTC (Coordinated Universal Time, CEST minus two hours), the first image was acquired at 01:59 and 40 seconds UTC (03:59:40 CEST). The yellow line indicates the locations at which MASCOT was still descending towards Ryugu and where it could be identified in the ONC photos. The blue line below the yellow line is the projection of these positions onto the asteroid surface – so this shows MASCOT's flight route was rather straight, and the lander touched down on a large edgy block at around 02:23 and 24 seconds UTC. From there, the asteroid lander hopped along the curved horizontal line towards the east-northeast and was then repeatedly imaged by the ONC. At around 02:14 and 04 minutes UTC MASCOT came to rest at its first location on the asteroid. Meanwhile, Hayabusa2 ascended to a higher observation position over Ryugu, making it more difficult to identify MASCOT in the images due to the lower image resolution. On the second asteroid day, MASCOT's mobility mechanism was activated. Another image will show the lander on 4 October at 00:55 and nine seconds UTC.
Image: 1/3, Credit:

JAXA/U Tokyo/Kochi U/Rikkyo U/Nagoya U/ Chiba Inst Tech/Meiji U/U Aizu/AIST.

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Shadow of MASCOT over asteroid Ryugu during the descent
DLR's MASCAM camera on board MASCOT acquired this image as it descended to the asteroid Ryugu three and a half minutes after separating from its mothercraft Hayabusa2. In the image, the lander is approximately 20 metres above the asteroid's surface, and MASCOT's shadow can be seen at the top right.
Image: 2/3, Credit:

MASCOT/DLR/JAXA.

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MASCOT descends onto the asteroid
Artist's impression of MASCOT during landing
Image: 3/3, Credit:
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On 3 October 2018 at 03:58 CEST, MASCOT separated from the Japanese Hayabusa2 spacecraft and landed on Ryugu 20 minutes later. MASCOT operated for over 17 hours, collecting data from the asteroid surface.

MASCOT's 17 hours and 7 minutes on Ryugu

 

03:57:21 (CEST)

At an altitude of 51 metres above Ryugu, a bolt released behind a push plate ejected MASCOT from its transport bay in the Hayabusa2 spacecraft at a speed of approximately four centimetres per second. MASCOT drifted towards Ryugu without propulsion or control by the ground stations.

04:03

After approximately six minutes, MASCOT made its first contact with Ryugu – against a block of stone measuring 3-4 metres. The Optical Navigation Camera (ONC) on Hayabusa2 recorded the process in high-resolution images. At the same time, the DLR MASCAM camera acquired 20 images of the asteroid during the descent. MASCOT landed precisely on the designated target area MA9 (= 'Alice's Wonderland'). This is located at 300 degrees east and 30 degrees south.

~04:34 at location 1

After another approximately 31 minutes and several ground contacts, MASCOT reached its first rest position. On the asteroid, it is daytime at the landing site and the surface measurements begin.

~06:30

The DLR control centre in Cologne recognises that MASCOT is lying on its back and cannot carry out its experiments as planned.

~09:20

From Earth, an unscheduled command is sent to Hayabusa2 and from there to MASCOT to activate the swing arm to position the lander into the orientation envisaged for the experiments. Radio signals to the mission, which is some 300 million kilometres away, have a transit time of 18 minutes one way.

~09:52

MASCOT has completed its first day/night cycle. The second day on Ryugu begins.

~10:30 at location 2

The manoeuvre produced the desired result. MASCOT is in the correct orientation, is now ready for use, and will automatically resume its four experiments.

~12:51

The second daylight phase on Ryugu slowly comes to an end and MASCOT rotates with Ryugu into its second night.

~17:28

The third day on Ryugu begins for MASCOT.

~18:29 at location 3

MASCOT successfully executes a ‘Mini-Move’. This manoeuvre was commanded by the operations team in Cologne in order to optimise the position of the experiment sensors. Further scientific investigations were then carried out.

~20:04 at location 4

The final 'jump' for MASCOT was commanded and the lander entered the ‘end-of-life’ phase. Further scientific investigations were carried out.

21:04

The end of the third day on Ryugu approached for MASCOT. Meanwhile, more than 16 hours had passed – the expected maximum battery life for MASCOT. Contrary to expectations, the battery still delivered some power before the contact with MASCOT broke off due to entry into a radio shadow and the approaching night. Instead of 16 hours, the experiments functioned for 17 hours and 7 minutes.

Contact

Dr. Tra-Mi Ho

German Aerospace Center (DLR)
Institute of Space Systems
Robert-Hooke-Straße 7, 28359 Bremen

Falk Dambowsky

Head of Media Relations, Editor
German Aerospace Center (DLR)
Corporate Communications
Linder Höhe, 51147 Cologne
Tel: +49 2203 601-3959

Christian Krause

German Aerospace Center (DLR)
Microgravity User Support Center (MUSC), Space Operations and Astronaut Training
Linder Höhe, 51147 Cologne