Toru Yamamoto

Autonomous Precision Orbit Control Considering Observation Planning: ALOS-2 Flight Results

Earth-observation satellites carrying synthetic aperture radar instruments have stringent requirements on control of Earth-referenced repeat-track orbits. This precision control leads to frequent orbital maneuvers, thus burdening daily ground operations. To achieve high accuracy with minimal ground-based workload, we propose a novel autonomous orbit control method that allows both in-plane and out-of-plane maneuvers to be planned and performed autonomously. Furthermore, a maneuver slot concept is proposed to prevent conflicts with payload data-take opportunities. The proposed method has been implemented on the Advanced Land Observing Satellite-2 and has been in practical use since Augustxa02014. This is the first attempt to apply autonomous precision orbit control within a tube-shaped control window for regular operation of an Earth-observation satellite. Details of the proposed method and Advanced Land Observing Satellite-2 flight results are presented in this paper, and experiences and lessons learned fro...

Formation Flight Astronomical Survey Telescope (FFAST) mission in hard x-ray

A formation flight astronomical survey telescope (FFAST) is a new project that will cover a large sky area in hard X-ray. In particular, it will focus on the energy range up to 80keV. It consists of two small satellites that will go in a formation flight. One is an X-ray telescope satellite carrying a super mirror, and the other is a detector satellite carrying an SDCCD. Two satellites are put into a low earth orbit in keeping the separation of 12m. This will survey a large sky area at hard X-ray region to study the evolution of the universe.

Autonomous precision orbit control of ALOS-2 for repeat-pass SAR interferometry

ALOS-2, the next-generation Japanese SAR satellite, is designed to perform autonomous precise orbit control of Earth-referenced repeating orbits for effective repeat-pass SAR interferometry. The orbit control accuracy requirement of ALOS-2 is 500m (95%) with respect to the reference Earth-fixed flight path. This accuracy is guaranteed for all latitudes by not only drag-makeup maneuvers but also frequent inclination maneuvers. The on-board software of ALOS-2 can handle operations of orbit determination, maneuver prediction and planning, and maneuver executions for both drag-makeup maneuvers and inclination maneuvers. This feature of autonomy is expected to be great help for efficient ground operations of ALOS-2.

ALOS-2 orbit control and determination

The Advanced Land Observing Satellite-2 (ALOS-2) carries the state-of-the-art L-band Synthetic Aperture Radar (SAR) called PALSAR-2 which succeed to the ALOS/PALSAR. ALOS-2 was launched on 24th May 2014, and is performing the initial functional verifications of onboard components and systems. This paper describes the initial launch operation results, and the plan of the performance evaluation regarding to the orbit control and determination.

Contactless Space Debris Detumbling: A Database Approach Based on Computational Fluid Dynamics

This paper aimed to investigate the feasibility of a contactless method to detumble space debris by using thruster plume impingement during proximity operation. To detumble the rotational debris, t...

3-Axes Attitude Estimation Experiments Using CCD Earth Sensor

Abstract The CCD Earth Sensor (CCDESA) is an attitude sensor that estimates three-axis attitude angles using the Earths images. Current Earth sensors detect infrared rays radiated by CO 2 , however, the CCDESA detects the Earth by acquiring visible rays with a Charge Coupled Device (CCD). This CCDESA is a mission sensor of μ-LabSat which was launched by H-IIA as a piggyback satellite in December 2002. This paper discusses the CCDESA and the results of the on-orbit experiments.

Development of Attitude Control System of Micro LabSat

Abstract Micro LabSat is a 50(kg) class micro satellite that was launched on December 14, 2002. Micro LabSat switches attitude control modes according to the operation mode. In the nominal operation mode, spin-stabilized control is used. In the mission mode, three axis control is used. Micro LabSat carries only simple low cost sensors for attitude determination. This paper describes design and development of the Micro LabSat attitude control system.

On-Orbit Experiment of Motion Estimation and Tracking of Tumbling Object in Space

Abstract Capture of tumbling objects in space will be one of important on-orbit service technologies in future. It requires a series of technologies such as camera-image tracking of the target, target attitude motion estimation, and attitude control of the chaser to approach and grasp the target. Based on the theoretical and simulation-based research, University of Tokyo successfully performed on-orbit experiment of some of these technologies on a NASDAs (currently JAXAs) microsatellite named “µ-LABSAT.” In this paper, the objectives and procedure of these experiments, the control and estimation algorithms and the results will be described.