North Korean recon satellite launch

North Korea has announced booster-stage drop areas for its upcoming satellite launch. They earlier said they want to launch satellites to sun-synchronous 97 degree orbit, but the second stage drop zone would indicate a 73 degree orbit.

Three scenarios have been proposed:

• A) Stage 2 dogleg

  Second stage changes direction prior to burn; stage 3 in line with stage 2, 73 deg orbit. (me)

• B) Stage 2 restart and divert

  Restartable second stage changes direction after main burn; makes second burn to reach 73 deg; third stage in line with first stage direction; 97 deg orbit. (Credit: Marco Langbroek ).

• C) Stage 2 and Stage 3 dogleg.

  Second stage changes direction prior to burn; third stage further changes direction prior to its burn; 97 deg orbit, but with orbital plane further east. (Credit:Bob Christy and @LH2NHI )

Here is a more detailed breakdown:

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Scenario	A	B	C
Event
	Stage 1 burnout and sep	Stage 1 burnout and sep	Stage 1 burnout and sep
	Fairing sep	Fairing sep	Fairing sep
	Stage 2 yaw 24 deg	Stage 2 yaw 17 deg	Stage 2 yaw 24 deg?
	Stage 2 burn	Stage 2 burn	Stage 2 burn
			Stage 2 yaw 45 deg
	Stage 2 sep from 3	Stage 2 sep from 3	Stage 2 sep from 3
		Stage 2 yaw 90 deg
		Stage 2 restart 1.9 km/s
	Stage 3 burn 3.6 km/s	Stage 3 burn 3.6 km/s	Stage 3 burn 4.2 km/s
	Stage 3 sep from payload	Stage 3 sep from payload	Stage 3 sep from payload
1st S Eq Crossing	132E	118E	122E
dV relative to A	0.0	1.9	0.6 km/s
Impulse relative to A	0.0	1.9 x M2	0.6 km/s x M3

Note that scenario B involves a much larger impulse (big delta-V on the massive stage 2) compared to C (smaller delta-V on the much less massive stage 3).