In the trajectory design to Jupiter, various interplanetary flight modes have been investigated. In this paper, the general characteristics of two interplanetary flight modes, that is, deep space ΔV-Earth gravity assist trajectories and Venus-Earth gravity assist trajectories, are considered. Each mode is evaluated in terms of required ΔV and flight time, and the periodicity of the launch opportunity for each mode is classified. Also, the solutions are obtained by a new trajectory generation method which seeks the optimal trajectories including the intermediate impulses and the powered swingbys.
The absorption of CO2 and O2 gas into the chlorella suspension and the stripping of O2 gas generated by photosynthesis of chlorella through the hydrophobic microporous hollow fiber membrane of polypropylene took place. The chlorella suspension flowed inside the hollow fibers and the gas mixture of CO2 and air flowed outside them. The following results were obtaind: (1) Overall mass transfer coefficient of CO2 and O2 gas for absorption depended only on the flow rate of suspension in the fibers, and was correlated by the dimensionless equation given below. Sh=A(Pe)1/3. (2) The photosynthetic reaction rate did not depend on the CO2 concentration in the suspension in the range of 1.5 to 5.0mol·m-3. (3) The supply of CO2 gas and the stripping of O2 gas generated by photosynthesis could be carried out with the same membrane module. (4) The membrane area required to get the maximum generation rate of O2 gas can be estimated when overall mass transfer coefficient, chlorella concentration and CO2 concentration in feed gas mixture were given.
This paper presents a method for calculation of the unsteady force, the moment, and the pressure distribution on the body in a two dimensional flow using the discrete vortex method. The body surface is represented by discretized point vorteces, and the force and the moment are obtained by integrating the pressure along the body surface. A mathematical formulation is presented for a flat plate, and this is extended to arbitrary shaped bodies (a square cylinder as an example). The pressure distribution is obtained by estimating the argument of the logarithmic singularities. This method is direct in its derivation and applicable to the cases for which the so-called generalized Blasius theorem or the control volume method are difficult to be used. It is also shown that the force obtained by the present method and that by the above mentioned two methods have some difference. This difference is considered to be caused by the mathematical incompleteness of the discrete vortex method.
Preliminary experiments of producing atomic oxygen for space environmental testing were conducted. O-atoms were generated by injecting molecular oxygen into a preionized argon plasma. A mixture of argon plasma and oxygen was expanded through a sonic orifice into a low pressure chamber as a freejet. To confirm the generation of O-atoms and to examine possibility of forming a molecular beam from the supersonic freejet, population densities of the electronic excitation levels 3p3P and 3p5P of atomic oxygen were measured along the freejet centerline. The results show that the population densities satisfied the low Earth orbit conditions.