Missile Technology Basics David Wright Senior Scientist and - - PowerPoint PPT Presentation
Missile Technology Basics David Wright Senior Scientist and Co-Director, Global Security Program Union of Concerned Scientists June 19, 2014 dwright@ucsusa.org Outline Trajectory Basics: Phases of flight Speed, angle, range
David Wright
Senior Scientist and Co-Director, Global Security Program Union of Concerned Scientists
June 19, 2014
dwright@ucsusa.org
Physics View of a Ballistic Missile
> ~500 km, that part of the trajectory where atmospheric drag is negligible
ranges
< 1,000km
1,000-3,000 km
3,000-5,500 km
> 5,500 km Range is not an intrinsic characteristic of a missile, since it depends on the payload.
Example: U.S. Trident SLBM Fully loaded: 8 warheads (1,500 kg) Range = 7,500 km Half loaded: 4 warheads (750 kg) Range = 11,000 km
Lofted Depressed (minimum-energy) Maximum range
2000 4000 6000 8000
Range (km)
10000 500 1000 1500 2000 2500
Altitude (km)
Variation in Range with Burnout Angle
Maximum range (minimum-energy)
Powered flight
Range (km)
2000 4000 6000 8000 10000 12000
Burnout Speed (km/s)
2 3 4 5 6 7 8
Range (km)
100 200 300 400 500
Altitude (km)
50 100 150 200 250 300
A missile that can launch a payload to a maximum range of R can launch that same payload vertically to an altitude of roughly R/2
distances
even for long ranges
M dV dM Ve Conservation of momentum:
Ve = exhaust velocity
Mass flow rate
Nodong
1,200 km/0.7t
Scuds
300-500 km/1t
Musudan
3,000 km/0.75t
TD-2/Unha-3 TD-1
(untested)
Missile Ve
(km/s) Mass flow rate (kg/s) Thrust (kN) Mass (tons) (no payload) Propellant Mass (tons)
Ms/Mp
Range/ payload (km & kg)
Scud-B
2.3 58 130 4.9 3.8 0.29 300/1,000
Nodong
2.3 130 290 14.3 12.4 0.15 950/1,000
TD-2 (stage 1)
2.3 520 1200 71.3 64.0 0.11 2,000/1,000
Musudan (est)
2.7 96 254 18.6 17.1 0.088 2,700/1,000
Titan II (stage 1)
2.9 803 2090 122 118 0.034
Evolution of North Korean missiles Changing Ve:
Scud, Nodong, and TD-2 use:
Musudan is thought to be a version of the Soviet SS-N6 missile
Missile Ve
(km/s) Mass flow rate (kg/s) Thrust (kN) Mass (tons) (no payload) Propellant Mass (tons)
Ms/Mp
Range/ payload (km & kg)
Scud-B
2.3 58 130 4.9 3.8 0.29 300/1,000
Nodong
2.3 130 290 14.3 12.4 0.15 950/1,000
TD-2 (stage 1)
2.3 520 1200 71.3 64.0 0.11 2,000/1,000
Musudan (est)
2.7 96 254 18.6 17.1 0.088 2,700/1,000
Titan II (stage 1)
2.9 803 2090 122 118 0.034
Evolution of North Korean missiles
Nodong engine is essentially a scaled-up Scud engine.
Increasing mass flow:
Missile Ve
(km/s) Mass flow rate (kg/s) Thrust (kN) Mass (tons) (no payload) Propellant Mass (tons)
Ms/Mp
Range/ payload (km & kg)
Scud-B
2.3 58 130 4.9 3.8 0.29 300/1,000
Nodong
2.3 130 290 14.3 12.4 0.15 950/1,000
TD-2 (stage 1)
2.3 520 1200 71.3 64.0 0.11 2,000/1,000
Musudan (est)
2.7 96 254 18.6 17.1 0.088 2,700/1,000
Titan II (stage 1)
2.9 803 2090 122 118 0.034
Evolution of North Korean missiles
TD-2 first stage uses a cluster
M dV dM Ve
e e
dM MdV V dM
dV V M
Conservation of momentum gives:
Ve = exhaust velocity
i e f
ln ln
f f i i
V M f i e e f i V M
dM V dV V V V V M M M
Then:
Mi = initial mass Mf = final mass
the missile heavier and the forces greater.
same factor, you don’t gain any velocity.
Missile Ve
(km/s) Mass flow rate (kg/s) Thrust (kN) Total Mass (tons) (no payload) Propellant Mass (tons)
Ms Mp
Range/ payload (km & kg)
Scud-B
2.3 58 130 4.9 3.8 0.29 300/1,000
Nodong
2.3 130 290 14.3 12.4 0.15 950/1,000
TD-2 (stage 1)
2.3 520 1200 71.3 64.0 0.11 2,000/1,000
Musudan (est)
2.7 96 254 18.6 17.1 0.088 2,700/1,000
Titan II (stage 1)
2.9 803 2090 122 118 0.034
Evolution of North Korean missiles
MS/MP
0 .0 0 0 .0 5 0 .1 0 0 .1 5 0 .2 0 0 .2 5 0 .3 0
0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5
Nodong
Scud
Titan II Musudan TD-2
1 Stage: Total mass = 111 t Propellant mass = 100 t
MP = 100 t MS = 10 t Payload = 1 t
ΔV = Ve ln [ (100+10+1) / (10+1) ] = 2.3Ve
Staging leads to 43% increase in velocity 1 Stage: Total mass = 111 t Propellant mass = 100 t 2 Stage: Total mass = 111 t Propellant mass = 100 t
MP = 100 t MS = 10 t Payload = 1 t Payload = 1 t MP = 80 t MS = 8 t MP = 20 t MS = 2 t
ΔV = 2.3Ve
ΔV = Ve ln [ (111) / (8+20+2+1) ] + Ve ln [ (20+2+1) / (2+1) ] = 3.3Ve
DF-3 DF-4 CZ-1 SLV DF-5 DF-3: similar in size but more capable than TD-2 first stage CZ-1: China’s first satellite launcher
capable than Unha DF-5: China’s first ICBM
– A way to control the direction of thrust during boost phase – A way to know the missile’s location and velocity during boost – A computer to know when it has reached the velocity, angle, and altitude to reach its intended target – A way to terminate thrust at that point
Nodong engine Steering engine exhaust Unha first stage (rear view)
150 lb/ft2 = 7.5 kN/m2 2500 lb/ft2 = 125 kN/m2
V3 (J/m 2s)
108 109 10
1 0
101 1 101 2
Altitude (km)
10 20 30 40 50 60
Reentry Heating Rate
High (low drag) Low (high drag)
= 5 0 lb/ft
2 = 2 ,5 0 0 N/m 2
= 2 ,0 0 0 lb/ft
2 =
1 0 0 ,0 0 0 N/m
2
Drag ~ (ρV2)/β For lower β, RV slows at higher altitude, where ρ is small Heating rate ~ρV3
Low β: Mercury capsule Medium β: Titan reentry vehicle High β: MM-III reentry vehicle
– Local winds, density variations – Non-zero angle of attack – Corkscrewing or tumbling – Asymmetries of reentry vehicle
P
Statistical measure of accuracy Radius of a circle, centered on the mean impact point (P), that includes half of the impact point Sometimes called “Circle of Equal Probability”
Distance between P and aim point is a measure of systematic inaccuracy, called “bias”
Solid Propellant Motor Liquid Propellant Engine
DF-3 DF-4 CZ-1 SLV DF-5 DF-31A
DF-5: Liquid, 183 tons DF-31A: solid, ~63 tons mobile
(2.25 m diameter)
(2.3 m diameter)
Simorgh Safir Safir Shahab-3M Shahab-3 Shahab-2 Shahab-1 (Nodong)
(similar to Unha)
(Scud) (untested)