Mobile Asteroid Surface Scout (MASCOT) - Design, Development and Delivery of a Small Asteroid Lander Aboard Hayabusa2

MASCOT is a small asteroid lander launched on December 3rd, 2014, aboard the Japanese HAYABUSA2 asteroid sample-return mission towards the 980 m diameter C-type near-Earth asteroid (162173) 1999 JU3. MASCOT carries four full-scale asteroid science instruments and an uprighting and relocation device within a shoebox-sized 10 kg spacecraft; a complete lander comparable in mass and volume to a medium-sized science instrument on interplanetary missions. Asteroid surface science will be obtained by: MicrOmega, a hyperspectral near- to mid-infrared soil microscope provided by IAS; MASCAM, a wide-angle Si CMOS camera with multicolour LED illumination unit; MARA, a multichannel thermal infrared surface radiometer; the magnetometer, MASMAG, provided by the Technical University of Braunschweig. Further information on the conditions at or near the lander‘s surfaces is generated as a byproduct of attitude sensors and other system sensors. MASCOT uses a highly integrated, ultra-lightweight truss-frame structure made from a CFRP-foam sandwich. It has three internal mechanisms: a preload release mechanism, to release the structural preload applied for launch across the separation mechanism interface; a separation mechanism, to realize the ejection of MASCOT from the semi-recessed stowed position within HAYABUSA2; and the mobility mechanism, for uprighting and hopping. MASCOT uses semi-passive thermal control with Multi-Layer Insulation, two heatpipes and a radiator for heat rejection during operational phases, and heaters for thermal control of the battery and the main electronics during cruise. MASCOT is powered by a primary battery during its on-asteroid operational phase, but supplied by HAYABUSA2 during cruise for check-out and calibration operations as well as thermal control. All housekeeping and scientific data is transmitted to Earth via a relay link with the HAYABUSA2 main-spacecraft, also during cruise operations. The link uses redundant omnidirectional UHF-Band transceivers and patch antennae on the lander. The MASCOT On-Board Computer is a redundant system providing data storage, instrument interfacing, command and data handling, as well as autonomous surface operation functions. Knowledge of the lander’s attitude on the asteroid is key to the success of its uprighting and hopping function. The attitude is determined by a threefold set of sensors: optical distance sensors, photo electric cells and thermal sensors. A range of experimental sensors is also carried. MASCOT was build by the German Aerospace Center, DLR, with contributions from the French space agency, CNES. The system design, science instruments, and operational concept of MASCOT will be presented, with sidenotes on the development of the mission and its integration with HAYABUSA2

Simulation and Validation Strategy on Real-Time Autocoded Onboard Software for Formation Flying In-Orbit Ranging Demonstration

International audienceThis article gives an overview of the simulation and validation strategy used for a real- time onboard software (OBSW) module developed on Matlab/Simulink® environment and autocoded into C language using the Real-Time Workshop Embedded Coder® (RTW). This module is the key point of the Formation Flying In-Orbit Ranging Demonstration (FFIORD) on PRISMA satellite mission. To respect requirements on real-time execution conditions and software reliability for space missions, the OBSW module is carefully tested before delivery and integration. Interesting results are obtained based on an inconstancies analysis of the C code produced by RTW, which leads to “good practice” guidelines for Simulink model implementation. Actions realised through this experiment aim at providing a background for the development of adequate Independent Verification and Validation (IV&V) procedures. They give more confidence and experience on the Model-Based Design domain before applying it to large scaled projects

Simulation and Validation Strategy on Real-Time Autocoded Onboard Software for Formation Flying In-Orbit Ranging Demonstration

International audienceThis article gives an overview of the simulation and validation strategy used for a real- time onboard software (OBSW) module developed on Matlab/Simulink® environment and autocoded into C language using the Real-Time Workshop Embedded Coder® (RTW). This module is the key point of the Formation Flying In-Orbit Ranging Demonstration (FFIORD) on PRISMA satellite mission. To respect requirements on real-time execution conditions and software reliability for space missions, the OBSW module is carefully tested before delivery and integration. Interesting results are obtained based on an inconstancies analysis of the C code produced by RTW, which leads to “good practice” guidelines for Simulink model implementation. Actions realised through this experiment aim at providing a background for the development of adequate Independent Verification and Validation (IV&V) procedures. They give more confidence and experience on the Model-Based Design domain before applying it to large scaled projects

MASCOT—The Mobile Asteroid Surface Scout Onboard the Hayabusa2 Mission

International audienceOn December 3rd, 2014, the Japanese Space Agency (JAXA) launched successfully the Hayabusa2 (HY2) spacecraft to its journey to Near Earth asteroid (162173) Ryugu. Aboard this spacecraft is a compact landing package, MASCOT (Mobile Asteroid surface SCOuT), which was developed by the German Aerospace Centre (DLR) in collaboration with the Centre National d'Etudes Spatiales (CNES). Similar to the famous predecessor mission Hayabusa, Hayabusa2, will also study an asteroid and return samples to Earth. This time, however, the target is a C-type asteroid which is considered to be more primitive than (25143) Itokawa and provide insight into an even earlier stage of our Solar System