Page 236 - NAVAL SCIENCE 3 TEXTBOOK

242 NAVAl. SKILLS

c\'CI1 though it is se\'cn1l models later than the original design. the Homil/gguirinllccdepends 011 the missile picking up and track-
RJ.\ 1-66 Standard I missile. phased out of u .S. service in 2003. ing n target b)I means of radar, optical. or heat-seeking devices. The
homing system will follow an}' evasive maneU\'ers nttempted by
the target. and the missile is l~lSt enough to overtake most targets
Missile Components trying to outrun it. There arc several types of homing guidance.
Each guided missile has fOllr basic parts: the airframe. tile propul- In (Ictil'c hOlllillg guidance, a mdnr transmitter illld recei\'er are
sion system. the guidance system, and the warhead. The (Ii1/mllll! both located in the missile. The transmitter emits a signal that is
of a missile is the streamlined body that contains the other parts reflected off the target back to the receiver. Active homing is COIll-
plus the fuel. ~vlissile airframes ilre made of aluminum altoys, Il1ng- pletely independent of the launching ship or aircraft. In sCl1Iinctil'c
nesiulll, and high-tensile steel sheet, all of which are lightweight hOl1lillg guidancc, i1 radar tr<1l1smitteJ' is located 0 11 the lauIlch-
materials capnble of withstilllding e:\1reme heat and high pressure. ing ship or aircraft, and a receiver is in the missile. In pl15sil e 110111-
'
The proplllsion system must propel the missiJe at speeds suf- illg guidance, the missile picks up and tmcks n target b}1 detecting
ficient to minimize its vulnerability while maximizing the prob- some form of energy emitted by it. Sources of energy used for pas-
ilbilit)' of intercepting a target. Most missiles designed to operate sive homing include light, sound, or heat. Like active homing, pas-
at supersonic speeds, or partially above the atmosphere or in the sivc homing guidance is completely independent of the launching
water, are equipped with Iiquid- or solid-fuel propulsion systems ship or aircraft.
containing an oxidizer (oxygen-carrying agent). Subsonic nir- COllll1l(l/ld gllidnllce involves missile control by signals from
breathing "cruise" missiles carry only a petroleum-based fuel and the launch station. After the missile is Imlllched on an intercept
draw their oxygen from the atmosphere. which limits their operat- course, a computer tracks both missile and target and transmits to
ing altitude to about 70.000 feet. the missile orders to change its track in order to hit the target even
'J7Je w(I/'head is the high-explosi\'e payload of the missile. It though the target might take evasive nctiol1.
Illny be either conventional or nuclear or, in the case of a practice Beam ,.ider gllidm/ce requires the missile to follow a radnr
missile, may colltnin telemetry equipment. beam to the target. A computer within the missile keeps it centered
Most Navy guided missiles ha\'e one of fi\'e types of guidance within the radar bcam; several missiles mil)' ride the beam simul-
systems: preset gyro, inertial, homing, cOlllmand, or beam rider. taneously. If the missile wanders out of the benlll, it will i1utomati-
GPS-based guidance systems are coming into use on some newer call)' selt~destruct.
models ofTomailawk cruise missiles and precision ordnill1ce.
Preset gyro gllidal/ce uses gyroscopes to keep the missile all a
Uses of Guided Missiles
set course, with an on-bonrd computer constilntly checking angle
of climb and accelemtion. \Vhen the missile attains the preset The development of Illodern guided missiles hilS added a new
comse and vclocity, power is shut off and it continues to the target dimension to the attack and defense cnp<tbilities of the U.S. mili-
as a free (ballistic) projectile. till')'. \Vhile missiles cannot perform all thc functions of guns, they
Inertial guid(ll/ce makes use of a predetermined flight profile can have greater range. accuracy, ilnd pilyloads. Sen control remains
programmed into nn onboard missile computer. ~'I'lissile speed and ;:1 primary mission of the Navy. but with the nd\'ent of the Polaris,
course nre checked constantly, and the computer initiates correc- Poseidon, and, in the 1980s, the 'n'ident intercontinenl<ti ballistic
tions to keep it on track. missiles (ICln.'is), the sea also has become n hiding ilnd launching
place for our nation's IllOSt potent seaborne stmtegic power-pro-
jection system. ?\·fodern cruise missiles launched from the sea can
also project the Navy's power tar inlnnd.
The current fteet ballistic missile (FIlM). the Trident ICBM.
has il mnge of over 4,000 nautical milcs. \ "ith such a range. even
the most remote place on Earth can be reached by submarine-
launched Trident missile wnrheads. The Air Force has several
models of iCBJ\·is with mnges of over 3,000 Ilautical miles; the
.. dome g=-~ w:;pn Jhe'd ,G",on Milluteman is the most powerful of these, having il range of over
~7~ ~ ~ 5,000 miles. All of these ICBMs hnve I1llele-nl' wi.lI'heads.

radar autopilot accumulator Cert;:lin missiles are designed to intercept incoming enemy bal-
listic missiles and destroy thcm before they Cim reach their targets.
Sectional drawings of typical missiles, showing the usual location of These are the (lIllibnllistic llIissiles (ARMs). Thcy must have great
the various modules (top), and an active homing missile (bottom). acceleration and long range in order to intercept enemy ICBMs.
To date the United States has never deplo)'ed a fixed ABM s),stem