Samos 5

 1961-035B

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SAMOS 5 (FTV 2203) reached orbit on 1961 Dec 22 after launch by Atlas Agena B from Point Arguello Naval Missile Facility. The Atlas SECO (main engine cutoff) came late, giving an extra 0.1 km/s velocity to the Agena. The orbit achieved was about 230 x 650 km; without the excess velocity it would have been about 230 km circular. LMSC-448564 suggests that the orbit should have been 90.9 min, 230 x 410 km x 90.0. On this flight, the SPS was not carried on the Agena.

The payload was a Program 101B SAMOS film return satellite with a 1.7-meter focal length prototype panoramic camera. Three objects were cataloged in orbit, identified by NORAD as the payload, the Agena, and a `reflector', probably the mirror shown in the Lockheed document (see SAMOS 4).

Comparing with the E-5 mission profile, I identify these as the reentry vehicle, the Agena, and the mirror. The Agena and payload reentered within a few weeks, with their orbits on Dec 25 showing 187 km perigees. I concluded that the recovery attempt was initiated prior to Dec 25 (the date of the first element sets for the low orbit objects) but failed to completely deorbit the vehicle, perhaps because of the high apogee, leaving the Agena and capsule in a 187 x 300 km orbit. (Note: late 1980s editions of the SATCAT give the payload as Alpha Lambda 3, while mid 1990s editions claim it is Alpha Lambda 1; I suspect the reassignment is an error). The Perry history says that a faulty command triggered recovery on rev 6, but incorrectly says that the payload ended in a higher orbit.

Based on a 1960 briefing document, the mass breakdown was: 2580 kg on orbit, including 630 kg Agena dry, 320 kg Agena prop, 730 kg E-5 spacecraft, 900 kg E-5 reflector and RV. (These figures are converted from imperial units and are only accurate to 1 significant figure).

The HEXAGON mapping camera history quotes a 2615 kg mass on orbit, with 692 kg recovery capsule.

SAMOS 5
Date	Time	Event	Orbit
1961 Dec 22	1912:33	Launch by Atlas Agena B	NMFPA
	1914:52	BECO (T+2:19)
	1916:58	SECO (T+4:25), LOX depletion
	1917:10	VECO (T+4:37)
	1917:15	Atlas sep (T+4:42)
	1918:08	Agena burn (T+5:35)
	1921:48	Agena MECO (T+9:15)	95.0 min 230 x 650 x ? (VCR)
1961 Dec 23	0500?	Command programmer to recovery mode, rev 6
1961 Dec 23		Reflector jettisoned
		Agena B burn (deorbit attempt)
		Agena B MECO (premature)
		Payload RV separated
1961 Dec 24	0536	Reflector orbit	95.24 235 x 825 x 89.7
1961 Dec 25	2154	Agena orbit	89.32 187 x 294 x 89.6
1961 Dec 25	2157	Payload orbit	89.49 187 x 310 x 89.61
1961 Dec 28		Reflector orbit	94.1 237 x 706 x 89.5 (SATCAT)
1961 Dec 30	0542	Agena orbit	88.30 180 x 200 x 89.7
1961 Dec 31		Agena reentered (AlphaLambda2) over Borneo
1962 Jan 4	0449	Payload orbit	87.96 139 x 208 x 89.7
1962 Jan 9		Payload reentered (AlphaLambda3) over NW Canada	89.4 187 x 310 x 89.6 (SATCAT)
1962 Mar 13		Reflector orbit	94.1 244 x 702 x 89.6 (RAE)
1962 Jun 5		Reflector orbit	92.1 228 x 524 x 89.6 (RAE)
1962 Aug 3	1430	Reflector orbit	89.6 201 x 299 x 89.6 (RAE)
1962 Aug 12	1936	Reflector orbit	88.12 181 x 181 x 89.7
1962 Aug 14		SAMOS 5 reflector reentered (AlphaLambda1)