Iridium 4

 1997-020E

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The first batch of three Iridium satellites were ready for launch in Jan 1997, but a weather delay meant that another Delta carrying GPS satellite was launched first. When this Delta promptly exploded, the Iridium launch slipped four months and two more satellites were added to the cargo. The Delta 7920-10C made a two-burn ascent to a circular 86 degree orbit and the specially designed dispenser released the five payloads, SV004 to SV008. After the third satellite was deployed, the reaction control system of the Delta stage lost pressure. The final two satellites were safely ejected, although the last one ended up slightly low, but the vehicle was not oriented correctly for the depletion burn and ended up in a higher orbit instead of a lower one.

Iridium SV004
Date	Time	Event	Orbit
1997 May 5	1455	Launch by Delta 7920A-10C	V SLC2W
	1459	Thor sep
	1459	Delta burn 1
		10C fairing sep
	1506	Delta SECO 1
	1553	T+58? Delta burn 2
	1553	Delta SECO 2	625 x 643 x 86.4
	1557	Iridium 8 deploy
	1605?	Iridium 7 deploy
	1610?	Iridium 6 deploy
		Delta GN2 pressure drop
	1615?	Iridium 5 deploy
	1620	Iridium 4 deploy
1997 May 5			97.39 625 x 643 x 86.4
1997 May 14	0100	Iridium SV008 orbit raise phase
1997 May 15			97.44 626 x 645 x 86.4
1997 May 20	1324		98.07 664 x 668 x 86.4
1997 May 23	0335		98.07 663 x 669 x 86.4
	2135		98.87 702 x 707 x 86.4
1997 May 27	1735		100.44 773 x 785 x 86.4
1997 May 30	1546		100.40 771 x 784 x 86.4
1997 Sep 9	1547		100.40 772 x 782 x 86.4
1997 Sep 11	1114		100.15 761 x 770 x 86.4
1997 Sep 22	0430		100.18 760 x 773 x 86.4
1997 Sep 26	1528		100.38 769 x 784 x 86.4
1997 Sep 30	1315		100.40 771 x 783 x 86.4
1998 Mar 8			100.40 774 x 780 x 86.4
2004 Jun 29			100.40 775 x 779 x 86.4