Leaving the Earth

How Rockets Work Newton's Laws of Motion are: An object at rest tends to remain at rest An object in motion tends to remain in motion For every action there is an equal and opposite reaction

Newton’s Third Law

Rockets and Jets Rockets and jets work according to Newton's Third Law. They fire mass out at high speed and acquire velocity in the opposite direction. They do not need something to push against. They move because they are expelling exhaust gases at high speeds. The rocket or jet is pushing mass away, and the mass is pushing back (equal and opposite reaction.)

How Rockets and Jets Differ Rockets and jets expel mass by burning fuel. A jet gets the oxygen for combustion from the atmosphere A rocket carries oxygen in some form with it. Rockets can function outside the Earth's atmosphere; jets can't.

Rockets are Mostly Fuel (and Oxygen) A rocket or jet has to carry all its remaining fuel with it. (And oxygen, if it’s a rocket). Most of the mass of the Space Shuttle is fuel, and most of that is used to get the remaining fuel off the ground. The miles-per-gallon fuel economy of the Space Shuttle in its first foot off the ground is pretty terrible! (36,000 lb. to clear the tower)

About Orbits and Satellites Satellites travel elliptical paths with the center of the Earth at one focus (Kepler's First Law) Inertia causes object to continue moving in a straight line Gravity pulls object to Earth Balance between the two = orbit

Newton’s Mountain

Three Pioneers of Rocketry Konstantin Tsiolkovsky (1857-1935) Robert Goddard (1882-1945) Hermann Oberth (1894 – 1989)

Robert Goddard - First Liquid-Fuel Rocket, 1926

World War II

The V-1

The V-2

History That Might Have Been: If World War II had lasted a bit longer, it might have been fought with: Nuclear Weapons Guided Missiles Cruise Missiles Jet Aircraft

The Right Stuff Chuck Yeager - Supersonic Flight, 1948 Career fatality rate among military jet pilots is 25% To cope, they cultivate a superstition of “the right stuff” Title of Tom Wolfe book

From Sapwood to Sputnik An existing rocket, the SS-6, was used. The warhead section was removed A cluster of four more SS-6 engines was bolted around a central engine Very Dependable

Sputnik I October 4, 1957 S- (with) + put’ (path) + -nik (one who) = Sputnik Literally, one who follows the same path

Sputnik II and III

How Did Russia Beat the U.S? German scientists were not involved German scientists were NOT involved!! Germans built V-2 clones but did not work on main program All returned home by the early 1950’s They were debriefed on return - this has been known for decades

So why does the myth persist? Because it’s what we wanted to believe

Rockets and Geopolitics We relied on manned bombers We had bases close to Russia We led in miniaturization We decided to wait until nuclear weapons became smaller before putting them in missiles Result, we had smaller rockets And, most surprising of all---

Much of our early efforts went into cruise missiles!

How the World Looked to Russians in the 1950’s

The Russian Decision They had no bomber bases from which to attack the U.S. Missile Submarines were rudimentary at the time The only way to hit the U.S. was with missiles Thus, the Russians poured efforts into building huge rockets

Ouch!

Vanguard and Explorer

Explorer I Launch Complex

Historic Rockets, Cape Canaveral

Apollo 8 Launch Complex

Some Myths About the Space Program German scientists were the reason the Russians beat us into space Women astronauts were unfairly denied entry into the Mercury Program The X-15 could have evolved into a Space Shuttle NASA “deceived” the public by restricting astronaut press coverage The Russians never had a serious manned lunar program