scholarly journals Anisotropic pitch angle distribution of ~100 keV microburst electrons in the loss cone: measurements from STSAT-1

2012 ◽  
Vol 30 (11) ◽  
pp. 1567-1573 ◽  
Author(s):  
J. J. Lee ◽  
G. K. Parks ◽  
E. Lee ◽  
B. T. Tsurutani ◽  
J. Hwang ◽  
...  
Keyword(s):  
Attitude Control ◽  
Cyclotron Resonance ◽  
Low Energy ◽  
Energy Spectra ◽  
Magnetic Flux Tube ◽  
Angle Distribution ◽  
Attitude Control System ◽  
Loss Cone ◽  
Low Altitude ◽  
Balloon Experiments

Abstract. Electron microburst energy spectra in the range of 170 keV to 360 keV have been measured using two solid-state detectors onboard the low-altitude (680 km), polar-orbiting Korean STSAT-1 (Science and Technology SATellite-1). Applying a unique capability of the spacecraft attitude control system, microburst energy spectra have been accurately resolved into two components: perpendicular to and parallel to the geomagnetic field direction. The former measures trapped electrons and the latter those electrons with pitch angles in the loss cone and precipitating into atmosphere. It is found that the perpendicular component energy spectra are harder than the parallel component and the loss cone is not completely filled by the electrons in the energy range of 170 keV to 360 keV. These results have been modeled assuming a wave-particle cyclotron resonance mechanism, where higher energy electrons travelling within a magnetic flux tube interact with whistler mode waves at higher latitudes (lower altitudes). Our results suggest that because higher energy (relativistic) microbursts do not fill the loss cone completely, only a small portion of electrons is able to reach low altitude (~100 km) atmosphere. Thus assuming that low energy microbursts and relativistic microbursts are created by cyclotron resonance with chorus elements (but at different locations), the low energy portion of the microburst spectrum will dominate at low altitudes. This explains why relativistic microbursts have not been observed by balloon experiments, which typically float at altitudes of ~30 km and measure only X-ray flux produced by collisions between neutral atmospheric particles and precipitating electrons.

Search for low-altitude acceleration mechanisms during an auroral substorm

1968 ◽  
Vol 46 (8) ◽  
pp. 911-921 ◽  
Author(s):  
I. B. McDiarmid ◽  
E. E. Budzinski
Keyword(s):  
Pitch Angle ◽  
Magnetic Moments ◽  
Angular Distributions ◽  
Angle Distribution ◽  
Particle Interactions ◽  
Pitch Angle Distribution ◽  
Loss Cone ◽  
Black Brant ◽  
Auroral Substorm ◽  
Low Altitude

Two Black Brant rockets were fired simultaneously from Fort Churchill during an auroral substorm. Electron spectra and angular distributions were examined at altitudes up to 800 km in an attempt to observe the effects of acceleration or loss mechanisms acting on the particles at low altitudes. In particular, the variation of the pitch-angle distribution in the loss cone for electrons with energies greater than 40 keV and near 10 keV was examined as a function of altitude. It was found that the distributions within the loss cone at higher altitudes decreased more slowly with pitch angle than expected on the basis of the observed distributions at low altitudes if no forces other than the earth's magnetic field act on the particles. The discrepancy was larger for 10-keV electrons than for 40-keV electrons. It is concluded that mechanisms exist at altitudes below 800 km which can alter the magnetic moments and/or the energies of the particles. No satisfactory explanation of the observed discrepancy has been found. An attempt was made to interpret the results in terms of wave-particle interactions which could give rise to pitch-angle diffusion, but the magnetic-wave amplitude required is at least two orders of magnitude larger than observed values.

Double Fail-Safe Attitude Control System for Artificial Meteor Microsatellite ALE-1

2021 ◽  
Vol 19 (1) ◽  
pp. 9-16
Author(s):  
Shinya FUJITA ◽  
Yuji SATO ◽  
Toshinori KUWAHARA ◽  
Yuji SAKAMOTO ◽  
Yoshihiko SHIBUYA ◽  
...  
Keyword(s):  
Control System ◽  
Attitude Control ◽  
Attitude Control System ◽  
Fail Safe

Flight performance of the LES-8/9 three-axis attitude control system

1980 ◽  
Author(s):  
F. FLOYD ◽  
C. MUCH ◽  
N. SMITH ◽  
J. VERNAU ◽  
J. WOODS
Keyword(s):  
Control System ◽  
Attitude Control ◽  
Flight Performance ◽  
Attitude Control System

Design of attitude control system for ASRTU microsatellite

2020 ◽  
Vol 28 (10) ◽  
pp. 2192-2202
Author(s):  
Feng WANG ◽  
◽  
Shi-bo NIU ◽  
Cheng-fei YUE ◽  
Fan WU ◽  
...  
Keyword(s):  
Control System ◽  
Attitude Control ◽  
Attitude Control System

scholarly journals Low Power Cusped Field Thruster Developed for the Space-Borne Gravitational Wave Detection Mission in China

2021 ◽  
Vol 11 (14) ◽  
pp. 6549
Author(s):  
Hui Liu ◽  
Ming Zeng ◽  
Xiang Niu ◽  
Hongyan Huang ◽  
Daren Yu
Keyword(s):  
Low Power ◽  
Gravitational Wave ◽  
Attitude Control ◽  
High Efficiency ◽  
Experimental Investigations ◽  
Attitude Control System ◽  
Gravitational Wave Detection ◽  
Wave Detection ◽  
Wide Range ◽  
Institute Of Technology

The microthruster is the crucial device of the drag-free attitude control system, essential for the space-borne gravitational wave detection mission. The cusped field thruster (also called the High Efficiency Multistage Plasma Thruster) becomes one of the candidate thrusters for the mission due to its low complexity and potential long life over a wide range of thrust. However, the prescribed minimum of thrust and thrust noise are considerable obstacles to downscaling works on cusped field thrusters. This article reviews the development of the low power cusped field thruster at the Harbin Institute of Technology since 2012, including the design of prototypes, experimental investigations and simulation studies. Progress has been made on the downscaling of cusped field thrusters, and a new concept of microwave discharge cusped field thruster has been introduced.

scholarly journals Design, Ground Testing and On-Orbit Performance of a Sun Sensor Based on COTS Photodiodes for the UPMSat-2 Satellite

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4905
Author(s):  
Angel Porras-Hermoso ◽  
Daniel Alfonso-Corcuera ◽  
Javier Piqueras ◽  
Elena Roibás-Millán ◽  
Javier Cubas ◽  
...  
Keyword(s):  
Control System ◽  
Attitude Control ◽  
Response Curve ◽  
The Sun ◽  
Space Systems ◽  
Attitude Control System ◽  
Ground Testing ◽  
Sun Sensor ◽  
Early Results ◽  
Red Leds

This paper presents the development of the UPMSat-2 sun sensor, from the design to on-orbit operation. It also includes the testing of the instrument, one of the most important tasks that needs to be performed to operate a sensor with precision. The UPMSat-2 solar sensor has been designed, tested, and manufactured at the Universidad Politécnica de Madrid (UPM) using 3D printing and COTS (photodiodes). The work described in this paper was carried out by students and teachers of the Master in Space Systems (Máster Universitario en Sistemas Espaciales—MUSE). The solar sensor is composed of six photodiodes that are divided into two sets; each set is held and oriented on the satellite by its corresponding support printed in Delrin. The paper describes the choice of components, the electrical diagram, and the manufacture of the supports. The methodology followed to obtain the response curve of each photodiode is simple and inexpensive, as it requires a limited number of instruments and tools. The selected irradiance source was a set of red LEDs and halogen instead of an AM0 spectrum irradiance simulator. Some early results from the UPMSat-2 mission have been analyzed in the present paper. Data from magnetometers and the attitude control system have been used to validate the data obtained from the sun sensor. The results indicate a good performance of the sensors during flight, in accordance with the data from the ground tests.

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