2nd half of Navy

What happens when a bullet or shell is fired?

A charge is ignited in the back of the projectile. This
charge ignites the propellant in the cartridge or shell.
As the propellant ignites, gases are given off resulting
in temperatures and pressures rapidly rising. This
creates a force that sends the projectile down the
muzzle of the weapon.

Factors controlling projectile within gun tube

Projectile weight, Gas pressure, Barrel length, Friction, Barrel/Propellant/Projectile Temperature

What do interior ballistics determine

muzzle velocity. High muzzle velocity = long range

Propellant types

progressive, neutral, regressive

what effects exterior ballistics

gravity (drop), drag, coriolis effect

launching system requirements

compatibility, reliability, speed, safety

Impulse launchers

Projectile is ejected from container by burning a chemical propellant that acts only on projectile. ejector or gun type launchers (torpedo, free fall, CIWS)

Reaction launchers

provides its own thrust to separate itself from the launching system (rockets, missiles)

How do you reduce recoil in impulse launchers?

recoil/counterrecoil systems, soft recoil systems, muzzle brake, recoilless systems.

counter - recoil

forward movement of gun back into battery

muzzle brake

one or more baffles attached to the muzzle end of the barrel designed to reduce recoil forces

recoiless systems

propellant gases discharged rearward, large back blast. RPG

three basic types of reaction launchers

rail, zero-length, canister

reaction propulsion

on-board energy source creates thrust during flight

examples of reaction propulsion

propeller driven, rocket engine, turbo-jet and ram jet engine, cruise missiles, rocket engine, jet engine

weapon architecture factors

shape, sensor number and type, propulsion and fuel, warhead, expected target maneuverability, launch platform capabilities

missile / torpedo sections

Guidance/ control, warhead, propulsion, afterbody

missile control

canard - controls are forward, delayed response

wing - in middle, main lifting surfaces, immediate response

tail - aft, alters angle of attack

weapons that use guidance systems

underwater homing torpedoes, surface-to-surface guided missiles, intercontinental ballistic missiles, air to air, guided missiles, surface to air guided missiles.

Detect to engage for guided missiles

Boost (intertial), Midcourse (guided), Terminal (guided)

Types of Guidance Systems 

Command guidance - control by direct electromagnetic radiation or electronic input

Self contained - self guided

homing - reacts to target features

Self-contained Guidance Systems

Preset

GPS

Celestial - references position to fixed stars and adjusts (ICBM)

Intertial - senses weapon movement and makes adjustment

Terrestrial - compares actual terrain with predicted flight path and adjusts accordingly

preset homing logic

constant, programmed. cannot be changed

variable homing logic

adjusts during flight. pursuit, constant bearing, proportional navigation

variable homing logic - pursuit advantages and disadvantages

advantages:

simple logic, good for slow moving targets

dis:

high speed maneuvers in terminal phase

constant variable logic adv, disadv

adv:

better vs. fast targets, less maneuvering in endgame

diadv,

sensor and computation intesive

proportional navigation pros cons

pros,

simpler, more accurate algorithm

cons,

still sensor and computation intesive, less than constand bearing

Main purposes of a fuse

1. Keep weapon safe when not needed

2. arm weapon

3. detect targets

4. initiate warhead detonation

5. determine direction of detonation

High explosive train

detonator, booster, main charge

3 major components of a fuze

staffing and arming device (prevents unintentional warhead detontation), target detection device, detonator

types of tdds/fuzes

impact / contact (detonated by physical contact)

ambient (senses change in environment like hydrostatic pressure or air pressure from large blast weapons.),

timer / command, proximity tdd

Proximity fuzes

electro - optical, electromagnetic, acoustic, pressure, combination

Series reliablility

safety.

safing and arming devices arranged in series for safety, if one device fails the system fails

parallel reliability

fuctional

detonators and target sensors arranged in parallel for reliability, if one device fails there are alternate signal paths.

four traits of a useful chemical explosive

forms gasses, releases heat, controlled release, rapid reaction

explain the mach stem

from an above surface blast, incident waves reflect off of the ground, constructively interfering with another wave essentially doubling pressure.

fuzing mechanisms for torpedoes

influence, contact, both

types of mines

moored, propelled, oscillating (drifting), bottom

Mine delivery methods

air, surface, submarine, asymmetric (civilian)

Mine warfare

asset protection, interdiction, attrition, force multiplication, terrorism

Mine detonation

contact, command, influence

methods of detonation

magnetic, acoustic, pressure, combination

methods of mine clearing

cable cutting, towed sled, remotely operated robotic vehicles

special purpose warheads

cluster bomb, radiation, thermobaric, pyrotechnic, fuel air explosive

Fission

splitting a very heavy nucleus into 2 or more lighter nuclei

Fusion 

combining 2 or more lighter atoms into a larger one.

critical mass

mass of sufficient size and density to maintain reaction

subcritical

total nuber of nutrons declining

critical

number of nutrons not changing

supercritical

number of nutrons increasing (more power)

Fission warhead gun type

Two subcritical masses forced together quickly while injecting nutrons to form supercritical mass. requires bullet (little boy)

fission warhead implosion

subcritical density inside of hollow shell of high explosive implodes inward, compressing the material and sustaining chain reaction (fat man)

fusion warheads

use fission detonation to trigger fusion reaction. increases pressure 50 million times greater than atmospheric, temperatures reach 10^10 k.

Nuclear Weapons Classification

Tactical - eliminate personnel, <100 Ktons

Strategic - Vast area targets, >100 Ktons

weapons of terror - any yield, unpredictable, dirty bombs

primary effects of nuclear weapons

Blast = 50%

thermal radiation = 35%

Initial and residual radiation = 15%

rail gun

Use electricity to launch non-explosive tungsten rounds

rail gun pros

inexpensive, shoot far

rail gun cons

not effective against a lot of targets, rounds are unguided, takes a lot of power

Cyber domains

Users, devices / softwares, logic used by devices, circuits, physical locations of those things

pillars of cybersecurity

confidentiality

integrity

availability

non repudiation

authentification

does international law apply in cyberspace

yes

script kiddie

amerature hacker who lacks expertise

competitor

business competitor uses malicious means to attack org

insider

uses authorized access to harm organization. can be intentional or unintentional.

hacktivist

individual hacks network or device for political reasons (anonomous)

organized crime

group of hackers

nation state

government (stuxnet)

denial of service

russia in georgia

exploiting software vulnerabilities

north korea attacking sony

russia plan for cyberwarfare

organized crime

china strategy for cyberwarfare

ran by government