SLIM (Smart Lander for Investigating Moon) is the Lunar Landing Demonstrator which is under development at ISAS/JAXA. SLIM demonstrates not only so-called Pin-Point Landing Technique to the lunar surface, but also demonstrates the design to make the explorer small and lightweight. Realizing the compact explorer is one of the key points to achieve the frequent lunar and planetary explorations. This paper summarizes the preliminary system design of SLIM, especially the way to reduce the size.
SLIM project which aim for pin-point landing on the moon surface. For achieving this plan, it is necessary to estimate the flight position of the space probe. The estimation is performed by matching the detected craters with database. This paper introduces a crater detection method using Principal Component Analysis (PCA) and its evaluation. This method is capable of real-time processing under low computational resources such as Field-Programmable Gate Array (FPGA). In this research, we report improvement of robustness at detection and high accuracy of crater size measurement.
Energy absorbing system for landing gears is an important on the SLIM project. Open cell porous aluminum manufactured through 3D selective laser melting (SLM) process has been applied on the energy absorbing system. Compressive tests for cylindrical and hemispherical shaped porous aluminum with different porosities revealed the high potential as an energy absorbing component. Heat treatment after SLM processing is effective to increase the energy absorbing potential of the porous aluminum.
The landing radar employs a pulse-type radar using 4.3 GHz C-band microwave radiation. It has a wide beam for measuring the altitude in vertical direction, as well as four narrow tilted beams for measuring the velocity in horizontal direction. In this paper, development of the Bread Board Model (BBM), a field experiment, and the design of SLIM loading Flight Model (FM) are introduced. Furthermore, the radar simulator required for FM development of a radar is explained.
Next generation moon landing mission will require autonomous pinpoint landing capability because of requirements for landing on specific terrains in a limited area. This capability requires precise absolute self-localization of the lander during braking descent phase. The purpose of this paper is to propose an algorithm to estimate the lander position and to evaluate its mountability to a space-grade FPGA. In this method, the position estimation is performed by matching crater point patterns with database point patterns by finding topological correspondences using crater-based linear features. In addition, we confirmed the resource amount and the calculation time when this algorithm is implemented on the FPGA using high-level synthesis.
Inviscid and Reynolds-averaged Navier-Stokes (RANS) simulations of transonic flows around the NASA Common Research Model are conducted using the Cartesian flow solver UTCart. The immersed boundary method is used to represent the smooth geometry surfaces on the Cartesian grids. The wall function is combined with the immersed boundary method to reproduce the turbulent boundary layer on the geometry surface in the RANS simulations. In the inviscid calculations, the qualitative flow feature including the position on the shock-wave on the wing shows agreement with the reference result a body-fitted grid. In the RANS calculations, the trend of pitching moment and drag shows fair agreement with the reference result, while prediction of the flow separation at high angle of attack is still difficult. Compared with the reference result, the differences in the total drag coefficient at a moderate angle of attack on the medium grid (33 million cells) and the fine grid (99 million cells) are 31 drag counts (10%) and 20 drag counts (6.5%), respectively. Furthermore, each of the calculated aerodynamic coefficients shows a consistent trend of grid convergence toward the reference result.
Summary of First Aerodynamics Prediction Challenge (APC-I) is presented. The APC-I is a domestic CFD prediction workshop that was held on July 3, 2015. The test cases include aerodynamic prediction of NASA-CRM with and without aeroelastic effects, and its wake flow prediction. We compare the CFD results with JAXA’s wind tunnel measurements. There are 15 participants from government, academia, industry, and commercial. The CFD results submitted from the participants are compared and discussed.
Summary of Second Aerodynamics Prediction Challenge (APC-II) is presented. The APC-II is a domestic CFD prediction workshop that was held on July 6, 2016. The test cases include aerodynamic prediction of NASA-CRM with and without support effects, and buffet prediction. We compare the CFD results with JAXA’s wind tunnel measurements. There are 9 participants from national research agency, academia, industry, and commercial software vendor. The CFD results submitted from the participants are compared and discussed in the presentation.