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HIBARI (satellite)

HIBARI

Operator	Tokyo Institute of Technology
COSPAR ID	2021-102F
SATCAT no.	49400
Spacecraft properties
Manufacturer	Tokyo Institute of Technology
Launch mass	55 kg (121 lb)
Dimensions	50 × 50 × 50 cm (20 × 20 × 20 in)
Start of mission
Launch date	9 November 2021, 00:55 UTC
Rocket	Epsilon (No. 5)
Launch site	Uchinoura Space Center
Contractor	JAXA
Orbital parameters
Reference system	Geocentric orbit (planned)
Regime	Sun-synchronous orbit
Perigee altitude	560 km (350 mi)
Apogee altitude	560 km (350 mi)
Inclination	97.6°
Instruments
Ultraviolet telescope
Innovative Satellite Technology Demonstration Program

HIBARI is a space mission by Japan for a microsatellite that would test a new attitude control (orientation) method to achieve high accuracy pointing for its small telescope, and was launched on 9 November 2021 by an Epsilon launch vehicle as part of the Innovative Satellite Technology Demonstration Program-2 mission.^[1] The key technology to be tested on HIBARI is called "Variable Shape Attitude Control" (VSAC), and it is based on reaction torque by rotating its four solar array paddles.

Conceptual design[edit]

HIBARI is a space mission by the Japanese scientists from the Tokyo Institute of Technology to develop high pointing stability and agile maneuvering of a small satellite by using reaction torque of the satellite's structure.^[2][3] This technology, first presented in 2016,^[4] is hoped to substitute the use of reaction wheels and control moment gyroscopes (CMG), which arguably have difficulty achieving both agility and stability simultaneously.^[2] This capability would be useful for a very fast response to observe in the direction of gravitational waves or other transient astrophysical phenomena.^[3]

The spacecraft is a 55 kg (121 lb) microsatellite configured in a 50 cm (20 in) cube,^[3] where half of it would carry a small ultraviolet telescope to verify the pointing stability (< 10 𝑎𝑟𝑐𝑠𝑒𝑐²) and accuracy of the VSAC system. The orientation high accuracy would be achieved by rotating the arms of its four solar arrays in an orthogonal axis.^[2] Solar cells would be mounted on both sides of each of four solar array paddles.^[3]

References[edit]