Suzaku

 2005-025A

---

Astro-EII (named Suzaku after launch) was the replacement for Astro E. It had 4 XRT-I telescopes with 0.4m dia, f=4.75m, 175 shells, and one XRT-S with 0.4m dia, 4.50m, 168 shells, plus the HXD hard X-ray detector with 0.6 deg FOV. The telescopes are like those on Astro-E, but precollimator sections were added to reduce background, and the XRS detector was improved.

The XIS CCDs each have a 19 arcminute field of view. The long XRT has the XRS microcalorimeter in a 1.5m long dewar, giving an energy resolution of 6 eV with a 2.9 arcmin field of view in a 6 x 6 pixel array. The dewar is a 4-stage refrigerator with a mechanical cooler, a solid neon shell, a liquid helium stage, and an ADR (adiabatic demagnetizing refrigerator), putting the XRS focal plane at only 1.5 mK.

Although XMM-RGS and Chandra-LETG are more sensitive and higher resolution than XRS at soft energies, the reverse was to be true at 2-10 keV energies where XRS was designed to surpass other missions in sensitivity and resolution. The XRTs have 2 arcminute resolution, so the point source sensitivity would be worse than missions like Chandra.

Soon after launch a design error manifested. After several days observation of the internal calibration source, vented helium built up inside the spacecraft body and a thermal short developed between the cryogenic dewar and the structure, boiling off the cryogen and warming up the focal plane. Once gain there would be no astronomical observations with a spaceborne X-ray calorimeter. As a result of miscommunication between the various mission teams, it had not been realized that a design change in the spacecraft compared to the original Astro-E prevented gas vented from the instrument reaching the outside.

Suzaku nevertheless had a successful career using the XIS and HXD instruments which provided a broader spectral range than other then-operating missions.

ASTRO E-II was a stepped octagonal cylinder, 1700 kg mass, size 4.5m long (launch), 6.5m long (EOB extended), diameter 2.1 x 1.9m with 5.4m solar array span.

ASTRO-E2
Date	Time	Event	Orbit
2005 Jul 10	0330	Launch by M-V-6	USC
		T+1:15 St 2 burn
		T+3:06 Fairing sep
		T+3:20 St 2 sep
		T+3:22 St 3 nozzle extend
		T+3:25 St 3 burn (102s?)
	0335	T+5:07? St 3 burnout
		T+5:47 Begin attitude turn
		T+7:02 End attitude turn
	0351	T+21:47 Stage 3 sep	295 x 538 x 31.4
			550 x 550 x 31
		T+2d Spindown
		T+4d Solar panel deploy
		T+5d optical bench extends
2005 Jul 17		DV1	304 x 537 x 31.4
2005 Jul 17	2200?	DV2	356 x 536 x 31.4
2005 Jul 22	0020?	DV3	96.05 565 x 573 x 31.4
		XRS switchon
2005 Aug 8		XRS thermal failure
2006 Nov 9		XIS2 failed
2015 Jun 1		Power issues, intermittent comm
2015 Aug 26		end of ops
2015 Sep 2		transmitters off

Payload:

• XRS-2 Xray Microcalorimeter, 0.1-10 keV

• XIS-2 X-ray CCD camera, 0.1-10 keV

• HXD-2/PIN Hard X-ray Detector, PIN diode detector, 10-50 keV

• HXD-2/GSO Hard X-ray Detector, Collimator/scintillator, 30-700 keV

• XRT-2 X-ray telescope for XRS

• XRT-2 X-ray telescopes (4) for XIS

• EOB Extensible Optical Bench