Japan Aerospace Exploration Agency

The Director-general of the Institute of Space and Astronautical Science

Showa Denko K.k.

Junichiro Kawaguchi

Osamu Mori

Toshihiro Chujo

Takayuki Yamamoto

Shigehiro Chaen

Masanao Abe

Hirokazu Ishida

Tatsuaki Hashimoto

Akiko Nakamura

Shujiro Sawai

Akira Fujiwara

Yoji Shirasawa

Koji Nakaya

Yasuhiro Morita

Yoshitsugu Sone

Kohta Tarao

Yuichi Tsuda

Kosuke Akatsuka

Yasuhiro Kawakatsu

Norizumi Motooka

Hiroto Habu

To provide a sheet-like optical device capable of selectively emitting light whose optical path has a changed orientation. An optical device includes a first sheet and a second sheet. The first sheet is configured to be electrically switchable between a first state in which the first sheet extends along an in-plane direction orthogonal to a thickness direction and has transparency in the thickness direction, and a second state in which the first sheet has lower transparency in the thickness direction than the transparency in the first state. The second sheet has a prism surface on which an inclined surface inclined with respect to the in-plane direction is arranged along the in-plane direction, the second sheet facing the first sheet in the thickness direction.

Optical device, attitude control apparatus, and spacecraft

Provided is a jet system capable of regulating a pressure of a jet substance without using any high-pressure gas supply subsystem. In a storage section for storing therein a jet substance such as fuel or oxidizer, a pressurizing substance such as liquefied gas is stored in addition to the jet substance, to enable the jet substance to be supplied from the storage section according to pressurization from the pressurizing substance. A jet operation is performed while an internal pressure of the storage section lowered along with discharge of the jet substance therefrom is at least partially recovered by at least a part of the pressurizing substance vaporized in the storage section.

Jet system

A vapor jet system to continuously jet vapors while suppressing cavitation. One vapor jet system includes a liquid storage part for separately storing two or more kinds of mutually insoluble liquids; a jet orifice; and a jet control part. Jetting the vapors is from a state where pressure in the space storing the vapors in the liquid storage part is higher than the saturated vapor pressure in any of the two or more kinds of liquids. Alternatively, a vapor jet system can include a fluid storage part storing one kind of liquid and at least one kind of inactive gas having a composition different from the liquid; a similar jet orifice; and a similar jet control part. Jetting the vapors and inactive gas(es) is (are) from a state where pressure in a vapor storing space in the fluid storage part is higher than the saturated vapor pressure in the liquid.

Vapor jet system enabling jetting for many seconds using multiple kinds of mutually insoluble liquid gases as fuel

A torque generation system includes: a plurality of solar array panels and/or solar array panel divisions; and a torque controller configured to control an electricity generation ratio of each of the plurality of solar array panels and/or solar array panel divisions to generate torque.

Torque generation system, attitude control system for spacecraft, and relative position and velocity control system for spacecraft

A power generation apparatus, a power generation method, a decomposition-gas boiler, and a decomposition-gas turbine with which nitrous oxide may be used as an environmentally friendly energy source. A fuel gas including nitrous oxide (NO) is supplied to a decomposition reactor () in which a catalyst () for decomposing nitrous oxide is disposed. Steam is generated by a decomposition-gas boiler by heat recovery from decomposition gas (N, O) generated by decomposing the nitrous oxide, the steam generated by the decomposition-gas boiler is used to drive the rotation of a steam turbine to obtain motive power, and the motive power is subsequently used to drive a generator to obtain electrical power. Alternatively, the decomposition gas (N, O) generated by decomposing the nitrous oxide is used to drive the rotation of a decomposition-gas turbine to obtain motive power.

Power generation apparatus, power generation method, decomposition-gas turbine and decomposition-gas boiler

Disclosed is a liquid-fuel storage vessel for use in a vapor jet system to store liquid fuel, wherein the vapor jet system is adapted to jet the fuel in a state after being vaporized inside the liquid-fuel storage vessel, outside the liquid-fuel storage vessel, to obtain a thrust. The liquid-fuel storage vessel comprises: a hollow tank for storing the liquid fuel, wherein the tank has an ejection port for ejecting the vaporized fuel, outside the liquid-fuel storage vessel therethrough; a heating device for heating the tank; and a porous metal formed to have a plurality of interconnected cells and provided inside the tank, wherein at least a part of the liquid fuel is held in the cells of the porous metal, and heat energy given from the heating device to the tank is transferred to the liquid fuel through the porous metal to cause vaporization of at least a part of the liquid fuel. The liquid-fuel storage vessel of the present invention can obtain a stable thrust level and ensure spacecraft attitude control.

Liquid-fuel storage vessel and vapor jet system using the same

Disclosed is a distributed control method of cooperatively allowing a control strategy for satisfying a constraint on an aggregated resource and simultaneously achieving or maintaining a performance of a system to be determined in a real-time manner by any one of a plurality of entities which have the highest need for the resource at any given time, without providing a specified management entity. The proposed method or 'card game scheme' of the present invention is designed to dynamically carry out a function of satisfying a constraint on an aggregate resource and simultaneously achieving or maintaining a performance of the entire system, based on a distributed control with high flexibility, wherein an 'agent', i.e., a software having a function of performing autonomous determination and control, is set in each of the entities, to allow the entities to dynamically take turns to perform a processing of determining a strategy for resource allocation.

Autonomous distributed control involving constraint on resources

An ultrahigh altitude sun-synchronous orbit satellite system having one or plural satellites orbiting the sun such that the satellites revolve around the earth in a substantially circular or elliptic motion at an altitude of several million kilometers from the earth, beyond the sphere of earth gravity influence. The satellites are placed on an orbital plane relative to both the sun and the earth and keep a distance and geometry between the satellites, sun and earth substantially constant. The satellite system performs any one of the services of space observation, global observation, and satellite communication. The satellites orbit the sun with both inclination and eccentricity distinct from those of the revolution of the earth and revolve around the earth with a sun synchronous property in which the local solar time is kept constant at a point on the surface of the earth directly beneath the satellite.

Ultrahigh altitude sun-synchronous orbit satellite system

A method is disclosed for designing an orbit of a spacecraft which allows the spacecraft to take a small-radius halo orbit near a Lagrange point while avoiding the prohibited zone where the spacecraft may be shadowed or might be prevented from making communication. The method makes it possible to have a closed orbit although being similar to a Lissajous orbit, under a restricted condition where a propulsion force magnitude applied to a spacecraft is fixed, and where it rotates at a constant angular velocity, based on the equation of motion close to a Lagrange point. The method also provide a theory for guiding/controlling the orbit of a spacecraft, that is, the embodiment of the above orbit design method.

Method for designing an orbit of a spacecraft

In a method for injecting a plurality of spacecraft into different circum-earth or interplanetary orbits individually in a single launch, a plurality of spacecraft coupled to an assist module are injected into an interplanetary orbit having a periodicity synchronous with the earth's revolution period. Then, in a maneuver allowing the assist module to re-counter with and pass near to the earth (Earth swing-by), the assist module appropriately performs an orbital change maneuver and a separation maneuver for each of the spacecraft in a sequential order. Through these maneuvers, a closest-approach point to the earth is changed for each of the spacecraft so as to drastically change a subsequent orbital element for each of the spacecraft. The assist module takes a sufficient time to determine a target orbit for each of the spacecraft with a high degree of accuracy until a half month to several days before a closest-approach time in the Earth swing-by. Based on the determined orbit, the assist module makes an orbit correction of about several m/sec in a sequential order, and then separates the spacecraft therefrom in a sequential order. In this process, an inertia navigation is performed based on an accelerometer mounted in the assist module and information about attitude.

Method of injecting plurality of spacecraft into different orbits individually

The present invention provides a method and a device, which is in one hand implemented as a man-machine system in which the operations are shared such that a driver takes in charge of an inter-vehicle distance and speed control, while on the other hand a quantity of controls for stabilizing the inter-vehicle distance sequence is calculated automatically and additionally incorporated by the addition in respective vehicles. The stabilization of the inter-vehicle distance can be realized by employing the distributed control method in which a set of acceleration and deceleration information from a vehicle traveling ahead is appropriately integrated and transmitted in relay to a following vehicle. This enables the stabilization of the inter-vehicle distance sequence without requiring the inter-vehicle distance measurement in itself and the easy installation of equipment, and realizes a method in which safety is ensured by allowing the driver to still take charge of a local control.

Method and a device for stabilization control of a vehicle traffic volume

A large membrane space structure deployed and spanned by centrifugal force owing to the spin motion, contains a hub located at a central portion thereof and a sail including a plurality of petals attached to the hub by supports. Each of the petals has regions symmetrical to an imaginary center line passing through the center of the hub. Membranes are spanned on the regions. Each of the membranes is divided into parts of suitable shapes, and adjacent membranes are discretely connected to each other by bridge belts to suppress the residual crease strain. The petals are symmetric with respect to the center of the hub. Deployment force is provided in the circumferential direction by the introduction of imaginary tension lines. The petals may be connected to each other to help deployment.

Large membrane space structure and method for its deployment and expansion

When the operation of an electromagnetic thruster valve disposed in a fluid assage for establishing the connection between a gas tank and a thruster unit for jetting gas filled in the gas tank is controlled to follow a thrust command, rise time of thrust at certain thrust is measured based on a state of the operation of the electromagnetic thruster valve. Then, the measured value and a predetermined delay value are subject to a comparison. The obtained difference is used as previous delay time to correct delay time of operation control of the electromagnetic thruster valve with respect to a next thrust command when the operation of the electromagnetic valve is controlled.

Apparatus and method for controlling thruster valve

A sample collector of this invention includes a projectile projecting unit n which a projectile is loaded and which has a projecting outlet for projecting out the projectile loaded therein, an enclosed container which is communicated with the projecting outlet of the projectile projecting unit, which has a projectile passing hole arranged at a position located away from the projecting outlet, the passing hole allowing the projectile to pass through it after the projectile is projected out from the projecting outlet, and which covers a space between the projecting outlet of the projectile projecting unit, and a kinetic energy absorbing mechanism which is arranged around a projectile path between the projecting outlet of the projectile projecting unit and the projectile passing hole of the enclosed container. The kinetic energy absorbing mechanism may be an independent active type such as brushes or an integral passive type structured by a part of the container.

Growing community of inventors

Sagamihara, Japan

Junichiro Kawaguchi