Explorer 3

  1958-003

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Explorer III was launched on 1958 Mar 26 by Juno I from Cape Canaveral It achieved a 186 x 2800 km x 33 deg orbit, much more eccentric than the planned 351 x 2043 km x 34.1 deg one. Transmissions were interrupted on May 10 and at the time it was thought this was due to Eta Aquarid micrometeor impacts. Explorer III reentered on 1958 Jun 28.

Explorer III
Date	Time	Event	Orbit
1958 Mar 26	1738:03	Launch by Juno I
	1740	Redstone cutoff T+2:35
	1740	Redstone sep T+2:40
	1744	Stage 2 burn T+6:36
		Stage 2 cutoff T+6:44	-5000 x 352
	1745	Stage 3 burn T+6:44
		Stage 3 cutoff T+6:52	-3510 x 351
	1745	Stage 4 burn T+6:52
	1745	Stage 4 cutoff T+7:00	195 x 2810 x 33.4
	1749	T+11:54 Stage 1 impact range 1433 km
	1750	T+12:36 Stage 2 impact range 2081 km
	1752	T+14:15 Stage 3 impact range 3142 km
1958 May 10		Transmitters failed
1958 May 15		Low power transmitter back on
1958 May 15?		Low power transmitter failed
1958 Jun 28		Reentry

Payload:

• Cosmic ray package, Geiger counter

• Erosion gauge micrometeorite detector