Tenma

For other uses, see Tenma (disambiguation).

Tenma, known as ASTRO-B before launch, was a Japanese X-ray astronomy satellite developed by the Institute of Space and Astronautical Science. It was launched on 20 February 1983, using a M-3S rocket on the M-3S-3 mission. It was the second X-ray observatory successfully operated by Japan after Hakucho (CORSA-B),^[3][a] and it had a superior temporal and spectral sensitivity compared to its predecessor.^[5]

Tenma

Tenma (Japanese for "Pegasus")
Names	ASTRO-B
Mission type	X-ray astronomy
Operator	ISAS
COSPAR ID	1983-011A
SATCAT no.	13829
Mission duration	5 years, 9 months, 27 days
Spacecraft properties
Launch mass	216 kg (476 lb)[1]
Dimensions	0.94 m × 0.895 m (3.08 ft × 2.94 ft)
Start of mission
Launch date	20 February 1983, 05:10 UTC
Rocket	M-3S
Launch site	Kagoshima Space Center
End of mission
Disposal	Decommissioned
Last contact	17 December 1988[2]
Decay date	19 January 1989
Orbital parameters
Reference system	Geocentric[1]
Regime	Low Earth
Perigee altitude	489 km (304 mi)
Apogee altitude	503 km (313 mi)
Inclination	31.5°
Period	94 minutes
Instruments GSPC Gas Scintillation Proportional Counter XFC X-ray Focusing Collector HXT Hadamard X-ray Telescope
ASTRO program ← Hinotori (ASTRO-A) Ginga (ASTRO-C) →

Battery failure in July 1984 caused the operation to become limited, and continuing problems lead to the termination of X-ray observation on 11 November 1985,^[6] however it remained in sporadic contact until 17 December 1988.^[2] It reentered the atmosphere on 19 January 1989.^[b]

Highlights

• Discovery of the iron helium-like emission from the galactic ridge.^[6]
• Iron line discovery and/or study in many LMXRB, HMXRB and AGN.^[2]
• Discovery of an absorption line at 4 keV in the X1636-536 Burst spectra.