Thermal and Mechanical Investigation of a Preload Release Mechanism for a Space Probe under Laboratory Conditions

Der Vorspannungsabbau-Mechanismus der Asteroidenlandeeinheit MASCOT soll auf seine Funktionalität untersucht werden. Dazu muss ein Teststand entwickelt werden. Zusätzlich soll der Mechanismus derart verändert werden, dass der Erfolg des Abbauvorganges während des Fluges überprüft werden kann

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

Mechanical design of a modular experiment carrier for a terrestrial analog demo mission and its potential for future space exploration

The ROBEX (Robotic Exploration under Extreme Conditions) alliance formed by the German Helmholtz Association has the aim to find and use areas of overlapping competencies between institutions involved with the exploration of deep sea and space environment. To demonstrate the developed systems and technologies two test campaigns are conducted, one for the deep sea in the area of Svalbard, Norway and one on the volcano Mt. Etna in Sicily, Italy as an Moon environment analog test ground. The objective of the volcano mission is to demonstrate seismic experiments built-up and conducted autonomously by robotic elements. It shall serve as scientific benchmark to validate concepts reproducing and extending experiments from the Apollo program and at the same time demonstrate robotic capabilities to do so without direct human interaction. The overall test infrastructure consisting of a stationary lander, a mobile element and instrument carriers has been developed within the ROBEX alliance. The modular instrument carrier, referred to as Remote Unit (RU), is deployed and positioned by a robotic system and supplies the payload, in this case the seismometer, with power, data-handling and communication. It also provides mechanical interfaces to the lander and a grapple interface for robotic handling. The RU’s primary structure is a differential carbon-fiber-reinforced-plastic (CFRP) framework with a dedicated payload and bus compartment. Two types of RUs have been developed: one basic version that complies with a mass limitation of 3 kg (RU3) and one extended version of 10 kg (RU10). While the basic version has a fixed seismometer as well as limited lifetime due to the lack of photovoltaics, the extended version is equipped with a self-levelling seismometer, photovoltaics and an inductive power/data interface for unit charging and telemetry/telecommand (TT&C). Both designs use the identical main structure to meet the envisaged modularity approach. Even though the hardware was never meant to enter the space environment, the design approach for the units was always driven by principles which could be functional under space conditions while respecting the peculiarities and the financial framework of this terrestrial demonstration. This paper presents the functionalities of the RU with a special focus on the overall configuration, structural concept as well as included mechanisms. Moreover, starting with the baseline design for the terrestrial application, it analyses the differences and derives necessary changes and modifications to further develop the system towards a usage in an actual Moon mission

The MASCOT Separation Mechanism - A Reliable, Low-Mass Deployment System for Nano-Spacecraft

The Mobile Asteroid Surface Scout (MASCOT), an Asteroid Lander carried by the Hayabusa2 spacecraft, successfully landed on the Near-Earth Asteroid (162173) Ryugu on October 03, 2018. Hereby accomplishing the first ever landing of a European spacecraft on the surface of this type of celestial body. MASCOT was a prototype design of a new class of nano-size surface science packages for the exploration of small solar system bodies. The very low gravity (thus, very low escape velocity) of the target body required the design of a miniaturized deployment mechanism with a relatively small, well reproducible separation velocity. In addition, the mechanism also had to safely restrain the lander to the mother spacecraft during the launch and its 3.5 years cruise phase. In this paper, we describe in detail the design, numerical analysis and test of this newly developed separation mechanism. Furthermore, we compare the mechanism to other existing deployment systems and verify its performance with two independent analysis methods using actual flight data taken during the ultimate flight activation event, which initiated the successful delivery and surface operation of the MASCOT asteroid lande

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

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