Tomohiro Narumi

Real-time guidance of reusable winged space plane using genetic algorithm implemented on field programmable gate array

An efficient and flexible real-time guidance system is one of the critical needs in the development of a future reusable space transportation system. The genetic algorithm employs an optimization model called the evolution of life, which is generally considered numerically robust but involves an extremely high calculation cost. To reduce the cost, this paper proposes an efficient procedure that optimizes the coefficients of a set of prescribed input functions. In addition, to reduce the calculation time by more than one tenth, the optimization scheme is implemented on a field programmable gate array. The resultant optimization system is applied to an on-board guidance system that optimizes the trajectory of an experimental winged rocket in real time.

Use of elemental materials for the creation of an in-situ space dust impacts detector

This research focuses on space dust ranging from 100?m to 1mm. Space dust is mainly due to secondary space debris, which is called ejecta. The objective was to create an inexpensive space dust impacts detector using elemental materials. The detector is a glass/epoxy laminate printed circuit board with an area of 81cm2 for a weight of 30g. The detector can estimate the number of impacts and can give an approximation of the space dust size. The detector will be mounted on Horyu II that will operate in polar orbit for one year. In this article the authors report: a) the production of ejecta, b) the ejecta experiments on solar array coupon, aluminium honeycomb and CFRP/aluminium honeycomb, c) the detectors working principle and d) the estimations of the minimum detectable size of debris and collision probability. The ejecta experiments demonstrated that the ejectas mass is 7 to 46 times higher than the projectiles mass. For space dust in the range 100?m ? 600?m in diameter, the collision probability was calculated to be 16.5 percent. The detectors capabilities to detect broken lines and to transmit the data to the on-board computer were also demonstrated. This in-situ space dust impacts detector is thus a very promising research area for its lightness, low cost and its ability to provide immediate data on space dust population.

Design, development and flight experiment of a small reusable rocket that glides using two-stage parachute

This paper introduces the design, development and flight result of a small reusable rocket that glides using parafoil. The mission is autonomous guidance using parafoil, because the rocket must be recovered safely at target point. In order to avoid tangling of parafoil strings, roll control using aileron is employed to keep the ejection door upward. The rocket was launched at an annual rocket launch campaign held in France. The launch and roll control were successful, however the guidance was failed because parafoil strings tangled with rocket due to opening shock. The rocket landed at 480 meters from the target point