MAS­COT land­ing on Ryugu – op­er­a­tional se­quence

MASCOT's approach to Ryugu and its path across the surface
MAS­COT's ap­proach to Ryugu and its path across the sur­face
Image 1/3, Credit: JAXA/U Tokyo/Kochi U/Rikkyo U/Nagoya U/ Chiba Inst Tech/Meiji U/U Aizu/AIST.

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.
Shadow of MASCOT over asteroid Ryugu
Shad­ow of MAS­COT over as­ter­oid Ryugu dur­ing the de­scent
Image 2/3, Credit: MASCOT/DLR/JAXA.

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.
Artist's impression of MASCOT during landing
MAS­COT de­scends on­to the as­ter­oid
Image 3/3, Credit: DLR (CC BY-NC-ND 3.0)

MASCOT descends onto the asteroid

Artist's im­pres­sion of MAS­COT dur­ing land­ing

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.
04:03After 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 1After 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.
~06:30The DLR control centre in Cologne recognises that MASCOT is lying on its back and cannot carry out its experiments as planned.
~09:20From 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.
~09:52MASCOT has completed its first day/night cycle. The second day on Ryugu begins.
~10:30 at location 2The manoeuvre produced the desired result. MASCOT is in the correct orientation, is now ready for use, and will automatically resume its four experiments.
~12:51The second daylight phase on Ryugu slowly comes to an end and MASCOT rotates with Ryugu into its second night.
~17:28The third day on Ryugu begins for MASCOT.
~18:29 at location 3MASCOT 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 4The final 'jump' for MASCOT was commanded and the lander entered the ‘end-of-life’ phase. Further scientific investigations were carried out.

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.

  • Tra-Mi Ho
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Space Sys­tems
    Telephone: +49 421 24420-1171
    Robert-Hooke-Straße 7
    28359 Bremen
  • Falk Dambowsky
    Head of Me­dia Re­la­tions, Ed­i­tor
    Ger­man Aerospace Cen­ter (DLR)

    Cor­po­rate Com­mu­ni­ca­tions
    Telephone: +49 2203 601-3959
    Linder Höhe
    51147 Cologne
  • 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
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