Saturday, February 25, 2012

Intro to Volume One

Spaceflights to neighboring planets will become practical and eventually routine (much like airline travel today) because future propulsion methods will reduce travel time from months and years to weeks and perhaps even day.

Furthermore, spacecraft will maintain comfortable Earthlike conditions (gravity, atmosphere, comfortable billets, entertainment, etc) throughout the flight.

Equivalence Principle. Consider Einstein's thought experiment about an accelerating elevator. If the elevator accelerates at same rate as free falling objects near Earth's surface, then occupants will feel equivalent g-force as if they're static on Earth's surface.

Instead of Einstein's elevator, our Thought Experiment notionalizes a high performance spaceship to accelerate at rate, g, to produce gravity like force (g-force). However, our TE assumes that g-force propulsion can be achieved with slight enhancements to current technology.

Three sections:
  1. ***Thinking About It***
  2. ***Getting Ready***
  3. ***Getting There***

Different Expressions for g (acceleration of freely falling object near Earth's surface). After one day of g-force acceleration, vessel would achieve a velocity of  864 km/sec which equals 0.5 AU/day or 0.3% of light speed, c.
10 m/sec2 = 864 km/sec/day = g  = .5 AU/day2 = 0.3% c/day
"Galileo's famous demonstration at the Leaning Tower of Pisa showed that heavier objects fall at the same rate as lighter objects. In fact, he did numerous experiments in a more practical fashion, rolling balls down sloping troughes at different angles. He discovered that an object's freefall velocity increases with time, not with mass. In fact, numerous observations have determined that a freely falling object accelerates per the duration of the fall not the mass of the object."

G-force to other planets is more practical then current method of transfer orbits. Transfer orbits between planets now take months and years. This might work for robots and other AI devices; it won't work so well for humans and other biologics. By contrast, g-force propulsion would reduce interplanetary flight time to days.

On the other hand, g-force has its concerns. For example, g-force to Jupiter could increase ship's velocity to 2,700 km/sec at the midpoint. To decrease speed and still simulate gravity (thus, the term, "g-force"), spaceship reverses direction of fuel exhaust and decelerates at g for remaining days of travel.

Momentum Exchange: Expel small mass of high velocity gas in one direction, and much larger mass (rocket) slowly increases speed in opposite direction.
Mship × Vship = mfuel × vfuel
Let large space vessel's speed increase by 10 m/s for every second of powered flight. Thus, let Vship be a constant 10 m/s; then, change it into a rate by dividing both sides of equation by a second. (Recall: g, acceleration due to gravity near Earth’s surface, is approximately 10 m/sec2). Thus, TE assumes spaceship can expel enough high speed particles to provide 1-g force throughout the flight. This propulsion will bring ship to high velocity and simulate Earth gravity for ship and contents.
Mship × g = (mfuel × vfuel)/sec


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