Hexagon 20

 1986-F03

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The final KH-9 spacecraft, number 20 in the series, was launched on 1986 Apr 18. Only 8 seconds after launch, separation of insulation material in the Titan SRM 122 led to a burnthrough followed by a spectacular explosion 200 meters above Space Launch Complex 4-East. The SRM broke free of the stack, and some of the destruct system failed to work; a large chunk of the motor fell to the ground and exploded. The launch vehicle and spacecraft were completely destroyed, with serious damage to pads SLC4E and SLC4W. Following the loss of a KH-11 on the previous Titan launch and the loss of the space shuttle Challenger soon afterward, the NRO space program faced a crisis.

HEXAGON 20
Date	Time	Event	Orbit
1986 Apr 18	1845:01	Launch by Titan 34D-9	V SLC4E
	1845:09	T+0:08 Explosion at 250m
	1845	SRM exploded, destroyed vehicle (T+0:08)
		T+0:15 Shutdown
		T+0:16 Command destruct
	1845:29	T+0:28 Impact on SLC-4E