Vanguard 3

  1959-007

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The final Vanguard payload was the Magne-Ray satellite, a combined X-ray, meteoritic and magnetic field research satellite. The sphere was partly fiberglass and partly magnesium. It was the payload for TV4BU which for this last Vanguard flight carried a new third stage, the ABL X-248-A2, later known as Altair. The X-248 was similar to GCR's stage, but with a fiberglass casing instead of steel. It had the designation 38-DS-3100 and serial number SV-59. The new third stage increased payload mass by 13 kg, or velocity by 0.9 km/s for the standard payload mass. TV-4BU was informally called SLV-7, and the '7' was painted on the vehicle. Altair would become widely used on Scout and Delta. After a successful launch on 1959 Sep 18, the Magne-Ray payload became Vanguard III.

Vanguard 3
Date	Time	Event	Orbit
1959 Sep 18	0520:07	Launch by Vanguard SLV-7	CC LC18A
	0522:32	T+2:25 Stage 1 sep
	0522:59	T+2:52 Fairing sep
	0524:30	T+4:22 Stage 2 burnout
	0528:59	T+8:51 Stage 2 sep	-5325 x 505 x 33
	0529:13	T+9:06 Stage 3 burn
	0529:25	T+9:18 St 2 apogee 3.92 km/s, 505 km
	0529:49	T+9:42 Stage 3 cutoff DV=4.39 km/s	512 x 3744 x 33
		Stage 2 impact 18 12N 56 45W
1959 Dec 12		End of transmissions

Payload:

• Magnetometer

• Solar x-ray detector