Ballistic Missiles and Getting Into Orbit

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 2

Ballistic Missiles and Getting Into Orbit

• Intercontinental Ballistic Missiles (ICBMs)– Understanding Ballistic Missiles

and Trajectories– Conic Sections– ICBM Trajectories– ICBM Development– The Anti-Ballistic Missile Treaty

• Launch Windows and Times– Getting Into Orbit– Launch Windows– Launch Time

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit SECTION 7.1 3

Understanding Ballistic Missiles and Trajectories

• Not all spacecraft launched into space stay there.

• Ballistic missiles only travel through space.

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Conic Sections• All objects moving under the influence of gravity

must follow paths that form conic sections.• Circles, ellipses, parabolas and hyperbolas are all

conic sections because they are all ‘slices’ of a cone.• Parabolas and hyperbolas are useful only for

interplanetary motion.• Circular and elliptical paths are for near Earth work.

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 5

Conic SectionsBallistic Trajectories

The shape of a Ballistic Trajectory is an ellipse that intersects the Earth at two points

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 6

ICBM Trajectories• Ballistics:

– Science dealing with motion, behavior, and effects of projectiles—especially bullets, bombs, rockets, and missiles.

– Science or art of designing and hurling projectiles to achieve a desired effect.

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 7

ICBM Trajectories (cont’d)• Ballistic trajectories

– Paths followed by non-thrusting objects– Objects moving under the influence of gravity – Most of the trajectory is outside Earth’s

atmosphere (ignore all other forces except for gravity).

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ICBM Trajectories (cont’d)Trajectory Example

As the man in the figure tries to squirt the dog, he has three basic options similar to the options with ballistic trajectories of rockets:

He can squirt the stream of water directly at the dog (low trajectory).

Aim the stream of water at a 45 degree angle (maximum range or accuracy).

Or, squirt the stream high into the air (high trajectory).

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 9

ICBM Trajectories (cont’d)Ballistic Trajectories

• Define ballistic trajectories by:– Rocket’s position (radius from the Earth’s center) at

burnout– Rocket’s velocity at burnout– Flight-path angle at burnout– Direction of flight at burnout– Latitude at burnout– Longitude at burnout

• Shape of ballistic trajectory: ellipse intersecting Earth’s surface at launch and impact

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 10

ICBM Development• ICBMs are long-range missiles using a ballistic

trajectory.• ICBMs differ little technically from other

ballistic missiles.• Ballistic trajectories have focused on being

able to throw things farther and faster.

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 11

ICBM Development (cont’d)• V2 was first real intermediate range ballistic

missile.• After the war, U.S. and USSR began race to

develop ICBMs. • Key players in global space program also took

part in developing ICBMs.

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 12

ICBM DevelopmentModern ICBMs and MIRVs

• Modern ICBMs typically deliver multiple independently targetable re-entry vehicles (MIRVs).– Each Re-entry Vehicle (RV) carries a nuclear-weapon

warhead.– Allows a single missile launch to strike a handful of targets.

• Proved to be an “easy answer” to deploying anti-ballistic

missile (ABM) systems: adding more warheads to a missile costs less than building the missiles to shoot down the additional warheads.

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 13

ICBM DevelopmentMinuteman

• Minuteman I and II were U.S. ICBMs in service from 1960 to 1997.

• Minuteman III entered service in 1978.• Minuteman had two innovations that gave it a

long practical service life.– Solid-rocket fuel technology.– Earliest use of integrated circuit for digital flight

computer.

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 14

ICBM DevelopmentMinuteman (cont’d)

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ICBM DevelopmentMinuteman (cont’d)

Early trajectory of a Minuteman Missile shown on it’s way to a test range

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 16

ICBM DevelopmentPeacekeeper

• First deployed in 1986.• Canceled, modified, and

reinstated over several administrations.

• U.S. had to remove it from service to meet SALT II treaty.

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 17

ICBM DevelopmentPeacekeeper (cont’d)

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ICBM DevelopmentICBM Missile Silos

Unit 2, Chapter 7, Lesson 7: Ballistic Missiles and Getting into Orbit 19

The Anti-Ballistic Missile Treaty

• Between U.S. and USSR to limit use of anti-ballistic missile systems in defending against missile attack.

• Only two nuclear powers—kept both from believing they could avoid a counter-strike.

• In force for 30 years from 1972-2002.• U.S. withdrew from treaty in 2002.