Detailed structural design and corresponding manufacturing techniques of the MASCOT Landing Module for the Hayabusa2 mission

The DLR Mobile Asteroid Surface Scout (MASCOT) is an approximately 11kg shoebox-sized lander platform developed in cooperation with CNES and JAXA for the Hayabusa2 (HY-2) Asteroid Mission, which was launched successfully in December 2014 to the C-class asteroid 1999JU3. Therefor the MASCOT Landing Module accommodates 4 instruments (camera, magnetometer, spectrometer and radiometer) of 3kg in total. Further it has a mobility mechanism for up righting and hopping, integrated into the common electronic box’ housing. The MASCOT structure itself consists of two separate main parts, the Mechanical & Electrical Interface Structure (in the following called Interface Structure) and the Landing Module. The Interface Structure is mainly made of unidirectional carbon fibre reinforced plastic (CFRP) struts, forming a highly stiff 680g weighting framework that is fixed in a cutout of one of the HY-2 side panels and encloses the Landing Module. To fixate the Landing Module within the Interface Structure one central connection bold pulls the Landing Module into four Interface Structure-sided bearings. The focus of this paper is on the only 550g lightweight, cubic Landing Module with its structural (detailed) design and corresponding manufacturing techniques. In contrast to the Interface Structure, the Landing Module is a CFRP/foam sandwich framework structure. Its architecture is realized in such a way that all interface loads from heavier subunits are only introduced as in-plane loads into one of the sandwich walls. The CFRP/foam sandwich struts have mainly unidirectional face sheets that are locally combined with ±45° CFRP fabric plies to account for local stress concentrations. Furthermore the fabrics provide enforcement against shear loads and connect adjacent framework walls to each other. At load bearing points the foam core is locally replaced by solid CFRP blocks, which provide sufficient out-of plane stiffness and an enlarged area for out-of plane shear load introduction. One of the six Landing Module’s outer sides is closed with a detachable Aluminium sandwich radiator that serves at the same time as main integration and late access opening. To interface the radiator structurally and thermally to the other foam sandwich walls a combined solution with and without inserts was applied. Besides to these mechanical aspects also cleanliness and contamination control aspects, e.g. how the foam core was protected and handled, are covered. The paper will close with a lessons learned section, covering the manufacturing and cleanliness aspects to be considered for a CFRP-sandwich structure

MASCOT - A Lightweight Multi-Purpose Lander Platform

The Mobile Asteroid Surface Scout (MASCOT) is a small box shaped ~ 9 kg lander, developed to support and enhance larger S/C's scientific possibilities. Its P/L compartment includes currently 3 experiments of in total 3 kg. Further a mobility mechanism is on board which allows hopping manoeuvres on the asteroid. The system consist of two structures, a lander unit and a mechanical I/F structure. Both are designed as framework structures made of solid CFRP and CFRP-foam sandwich respectively. By designing consequently under the use of the materials orthotropic properties and additional design features (e.g. insertless) a very lightweight and stiff structure has been realised. With respect to a fully aluminium design a save of 75% structural mass for the lander unit was achieved and the structure is ready to enter Phase C. Being part of JAXA's Hayabusa 2 mission the launch date will be in December 2014 heading to the C-class asteroid 1999JU3

The Development and first Cruise Activity of the MASCOT Lander onboard the Hayabuse 2 mission

Since December 2014 the Japanese spacecraft Hayabusa-II is on its journey to asteroid 1999 JU3. Like its famous predecessor it is foreseen 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 motherspacecraft'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 scienti c 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, amongst others, by 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 in the surface supported by an according attitude and motion sensing system and 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 (10kg), 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 over the final capabilities of the system as well as discuss the latest 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

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