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

Planetary Defense Ground Zero: MASCOT's View on the Rocks - an Update between First Images and Sample Return

At 01:57:20 UTC on October 3rd, 2018, after 3½ years of cruise aboard the JAXA spacecraft HAYABUSA2 and about 3 months in the vicinity of its target, the MASCOT lander was separated successfully by from an altitude of 41 m. After a free-fall of only ~5m51s MASCOT made first contact with C-type near-Earth and potentially hazardous asteroid (162173) Ryugu, by hitting a big boulder. MASCOT then bounced for ~11m3s, in the process already gathering valuable information on mechanical properties of the surface before it came to rest. It was able to perform science measurements at 3 different locations on the surface of Ryugu and took many images of its spectacular pitch-black landscape. MASCOT’s payload suite was designed to investigate the fine-scale structure, multispectral reflectance, thermal characteristics and magnetic properties of the surface. Somewhat unexpectedly, MASCOT encountered very rugged terrain littered with large surface boulders. Observing in-situ, it confirmed the absence of fine particles and dust as already implied by the remote sensing instruments aboard the HAYABUSA2 spacecraft. After some 17h of operations, MASCOT‘s mission ended with the last communication contact as it followed Ryugu’s rotation beyond the horizon as seen from HAYABUSA2. Soon after, its primary battery was depleted. We present a broad overview of the recent scientific results of the MASCOT mission from separation through descent, landing and in-situ investigations on Ryugu until the end of its operation and relate them to the needs of planetary defense interactions with asteroids. We also recall the agile, responsive and sometimes serendipitous creation of MASCOT, the two-year rush of building and delivering it to JAXA’s HAYABUSA2 spacecraft in time for launch, and the four years of in-flight operations and on-ground testing to make the most of the brief on-surface mission

The MASCOT lander aboard Hayabusa2: The in-situ exploration of NEA (162173) Ryugu

After 3.5 years of cruise, and about 3 months in the vicinity of its target, the MASCOT lander was deployed successfully on October 3, 2018 by the Hayabusa2 spacecraft onto the C-type near-Earth asteroid (162173) Ryugu. After a free-fall of 5 ​min 51 ​s from an altitude of 41 ​m MASCOT experienced its first contact with the asteroid hitting a big boulder. The lander bounced for ~11 ​min 3 ​s before it came to rest. MASCOT was able to perform science measurements with its payload suite at 3 different locations on the surface of Ryugu. It investigated the fine-scale structure, multispectral reflectance, thermal characteristics and magnetic properties. The surface consists of very rugged terrain littered with large surface boulders. The in-situ measurements confirmed the absence of fine particles and dust as already implied by the remote sensing instruments aboard the Hayabusa2 spacecraft. After about 17 ​h of operations, the MASCOT mission terminated with the last communication contact as its primary batteries depleted. This paper summarizes the MASCOT mission covering its four years of in-flight operations, its preparation for the descent, landing and in-situ investigation on the asteroid Ryugu until the end of its operation

MASCOT, the small mobile package on its piggyback journey to 1999JU3: pre-launch and post-launch activities

Since December 2014 the Japanese spacecraft Hayabusa2 is on its journey to asteroid (162173) 1999 JU3. Like its famous predecessor it is expected to study and return samples from its target body. This time, the mother spacecraft has several small passengers. One of them is a compact landing package called MASCOT (Mobile Asteroid surface SCOuT), which has been developed by the German Aerospace Centre (DLR) and the Centre National d'Etudes Spatiales (CNES). Once having been released from its mother spacecraft's cradle, MASCOT will descend to the asteroid and after a few bounces will come to rest at a certain location on the surface. Sitting on the surface, it will perform its scientific investigations of the asteroids surface structure, mineralogical and physical properties, thermal behaviour and magnetic effects by using its suite of four scientific instruments: a spectrometer (MicrOmega, IAS Paris), a camera (CAM, DLR Berlin), a radiometer (MARA, DLR Berlin) and a magnetometer (MAG, TU Braunschweig). These payload operations are made possible by, amongst others, a clever thermal subsystem design specifically devised to cope with the contrasting requirements of cold cruise and hot on-surface operations and a primary battery optimizing mass versus energy output. A mobility mechanism realizes locomotion on the surface supported by an attitude and motion sensing system. An intelligent autonomy manager which is implemented in the onboard software can operate MASCOT when ground intervention is not available. In a nutshell, with its many challenging technical hurdles that have been solved, the MASCOT lander can serve as a benchmark for extremely lightweight (10 kg), highly integrated mobile small body landing systems with onboard autonomy and high science output. This paper will summarize the mission and system development. We will provide an overview of the final capabilities of the system as well as discuss the last challenging pre-launch activities and tests. Further a summary and an outlook regarding the already performed as well as upcoming post-launch activities will follow. Lessons have been learned and will be told to be ready for future upcoming missions for small solar system body exploration

MASCOT - a Mobile Lander on-board Hayabusa2 Spacecraft - Status and Operational Concept for the Asteroid Ryugu

MASCOT (‘Mobile Asteroid Surface Scout’) is a 10 kg mobile surface science package on board JAXA’s Hayabusa2 sample return mission, currently on its way to the near-Earth asteroid (162173) Ryugu. The mission was launched in December 2014 from Tanegashima Space Center, Japan. The Hayabusa2 spacecraft will reach the target asteroid in summer 2018. Hayabusa2 will return its samples to Earth in December 2020. After arrival at the target asteroid ‘Ryugu’ a detailed mapping phase will be performed and the landing site of MASCOT will be selected. The deployment of MASCOT to the asteroids surface is planned for the beginning of October 2018. MASCOT has been developed by the German Aerospace Center (DLR) in cooperation with the Centre National d’Etudes Spatiales (CNES). The main objective of MASCOT is to perform in-situ investigations of the asteroid surface and to support the sampling site selection for the mother spacecraft. Mascot is equipped with four scientific instruments a wide angle camera, a hyperspectral infrared microscope, a radiometer and a magnetometer. The camera (MasCam) provides ground truth for the orbital measurements of the Hayabusa2 orbiter instruments and the in-situ MASCOT sensor suite as well as geological context of the samples. The radiometer (MARA) determines the surface brightness temperature, the thermal inertia of the surface material and the spectral slope in infrared. The radiometer field of view is correlated with the wide angle camera field of view. The magnetometer (MasMAG) observes the magnetic field profile during descent and bouncing and determines any global and local magnetization of the asteroid

MASCOT - a Mobile Lander on-board Hayabusa2 Spacecraft - Operations on Ryugu

MASCOT (‘Mobile Asteroid Surface Scout’) is a 10 kg mobile surface science package part of JAXA’s Hayabusa2 sample return mission. The mission was launched in December 2014 from Tanegashima Space Center, Japan. The Hayabusa2 spacecraft reached the target asteroid in summer 2018. After a mapping phase of the asteroid and a landing site selection process the MASCOT lander was deployed to the surface on the 3rd of October 2018. MASCOT operated successfully for about 17 hours on the surface of Ryugu. It performed three relocation manoeuvres and one “Mini-Move” and returned 128 MBytes of data. MASCOT has been developed by the German Aerospace Center (DLR) in cooperation with the Centre National d’Etudes Spatiales (CNES). The main objectives were to perform in-situ investigations of the asteroid surface and to support the sampling site selection for the mother spacecraft. These objectives could be reached successfully. On 6th December 2020 (JST) Hayabusa returned successfully asteroid samples to the Earth