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MASCOT (Mobile Asteroid surface SCOuT) is a small lander, carried on the Hayabusa2 mission, to be deployed onto the surface of asteroid 162173 Ryugu. Hayabusa2 is a Japanese Space Agency (JAXA) mission designed to rendezvous with Ryugu and return a sample. MASCOT was designed to study the geology, mineralogy, thermal properties, and magnetic field, and to provide ground truth for the Hayabusa2 observations and an in-situ context for the samples collected.

MASCOT is a 29.5 x 27.5 x 19.5 cm box with a mass of 9.8 kg. It has no landing mechanism but was dropped on to the surface from low altitude. It has a mass mounted on a rotatable swing-arm within the lander which allowed it to reorient itself after landing and also to "hop" to a new location on the asteroid's surface. It also has attitude sensors to determine its orientation to make corrections after landing or hopping.

The lander is composed of a lightweight carbon fiber structure and aluminum walls with radiators, heat pipes, and multi-layer insulation for thermal control. The box is divided by a central wall into two compartments: a warm compartment housing the electronics, batteries, and the hopping mechanism; and a cold compartment housing the scientific payload. It has two patch antennae to communicate with Hayabusa2 and a transciever operating at 954 and 958.5 MHz. Power was provided by a battery consisting of nine Li-SOCl2 primary cells that provide about 255 Whr and lasted about 17 hours.

MASCOT's science payload of about 3 kg, comprises four instruments: a wide-angle camera (MASCAM; MAScot CAMera); a hyperspectral microscopic imager (MicrOmega) to study the surface composition, a thermal radiometer (MARA; MAscot RAdiometer) to measure the surface temperature, and a magnetometer (MasMag; MAScot MAGnetometer).

Hayabusa2 launched on 3 December 2014 at 04:22:04 UT (13:22:04 local Japanese Time) from the Tanegashima Space Center on an H2A rocket. It used an Electric Delta-V Earth Gravity Assist technique to reach the asteroid, flying by Earth on 3 December 2015 with a closest approach at 10:07 UT, and arriving at asteroid 162173 Ryugu on 27 June 2018, stationkeeping at a distance of 20 km. The position was periodically lowered for observations and rover deployment.

On 3 October 2018 MASCOT was released from Hayabusa2 at 1:57 UT from 51 meters above Ryugu and fell to the surface. The rotating arm was used to place it in an observing position, from which it collected data for one day/night cycle of 7.6 hours, and then "hopped" to a new location. It made two hops and observed the asteroid over a total of almost 17 hours before the batteries ran out.

Alternate Names

  • Hayabusa2 MASCOT
  • Mobile Asteroid surface SCOuT
  • urn:jaxa:darts:context:instrument_host:lander.mascot

Facts in Brief

Launch Date: 2014-12-03
Launch Vehicle: H-2A
Launch Site: Tanegashima, Japan
Mass: 9.6 kg

Funding Agency

  • Japan Aerospace Exploration Agency (Japan)


  • Planetary Science

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail

Selected References

  • Ho, T.-M., et al., MASCOT—The Mobile Asteroid Surface Scout Onboard the Hayabusa2 Mission, Space Sci. Rev., 208, No. 1-4, 339-374, doi:10.1007/s11214-016-0251-6, Jul. 2017.
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