September 28, 2018

Mascot Lander

The MASCOT/Hayabusa2 lander benefits from an inheritance from the Philae/Rosetta mission (launched in 2004, arrival on the Churyumov-Gerasimenko comet in summer 2014) and from the studies carried out for the Marco Polo mission of ESA's Cosmic Vision programme.

Mission de Mascot - Crédits DLR
MASCOT/Hayabusa2 Mission - Credits DLR

MASCOT is a 10 kg lander with a 3 kg payload, of 0.3 x 0.3 x 0.2 m³ volume and a single energy source (of 220 Wh) allowing about a 12-hour mission duration.

The baseline design for MASCOT is as followsMascot Structure:

  • Payload: the payload consists in a suite of four instruments which fit into the payload compartment: a hyperspectral microscope (MicrOmega), a Camera (CAM), a Radiometer (MARA), and a Magnetometer (MAG).
  • Structure & Accommodation: the lander baseline design foresees a highly integrated carbon-fibre composite structure with a middle wall as main load bearing element. A common electronics box called E-box houses all the electronic. The lander is connected with the main Hayabusa2 spacecraft via a Mechanical and Electronical Support Structure, the "MESS".
  • Macot mobility mechanismMobility Mechanism: the mobility mechanism has two purposes:
    • uprighting MASCOT in the correct attitude after landing
    • providing a hopping capability to relocate MASCOT on a different site.
    The motion is generated by driving an off-centred mass to provide the adequate momentum.

  • Thermal Control: the thermal control concept is based mainly on passive means such as multi-layer insulations (MLI) and colour coatings. One exception to the passive concept is the heaters used for the thermal control of batteries and MicrOmega during cruise and commissioning.
    MASCOT battery
  • Power: the power and energy supply is maintained by a primary battery. The unregulated bus voltage is converted into auxiliary voltages for MASCOT electronics by an internal Power Control and Distribution Unit (PCDU) located in the E-box. During cruise and commissioning, the power will be supplied by Hayabusa2 via a regulated power line. The power subsystem is a French contribution to MASCOT.
  • Communications: the communication architecture is based on a redundant CCOM transceiver provided by JAXA and identical to MINERVA-II's small landers. The bit rate will be ~37kps for telemetry (TM) and ~1.7 kps for Cruise antenna mounted on the MESStelecommand. The RF channel (957 MHz) will be used both during the cruise and on asteroid phases.Mascot antenna For cruise operations, a dedicated MESS antenna is required whereas for on asteroid operations, the OME-A Hayabusa2 antenna is used.

    Two omnidirectional antennas are positioned on both top and bottom sides of MASCOT. The communications subsystem (CCOM transceiver excepted) is a French contribution to MASCOT.

  • Data Handling & On-board Computing: MASCOT contains a hot-redundant on-board computer (OBC) for running the on-board autonomy and dealing with health checking and gathering, compressing and storing the scientific data. A key application is the "MASCOT Autonomy Manager" (MAM) which controls the autonomous operations sequence.
  • Guidance, Navigation & Control: The key task of the GNC subsystem is to robustly detect the touch down and MASCOT's motion state or orientation on the asteroid's surface. The concept is based on thermal sensors and photoelectric cells whose measurements are integrated in navigation algorithms.