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starship-design: Re: starship design
In a message dated 9/23/97 3:43:57 PM, you wrote:
>I know about a type of ramjet starship that might be an achievable
>goal.I propose the following conceptual design. Use breeder type nuclear
>fission rectors to generate a few megawatts to a few gigawatts of
>electricity to power a ramjet starship.Use ultraviolet laser beams to
>ionize hydrogen gas in the path of the starship. Then use elecrostatic
>ramscoops to collect from one to a hundred grams of interstellar
>protons. An electrostatic ramscoop uses a negative elecrostatic field to
>attract interstellar protons and pull them inside the engine.
>The stength of of the natural electric field in interstellar space is 1.
>x 10(-19) electon volts . An elecrostatic ramscoop's ion collection
>radius is the distance at which the electric field of the ramscoop is
>greater in strength then the natural electric field of interstellar
>protons. The strength of a magnetic or electric field in a vacume
>declines in proportion to the inverse square of the the change in
>distance from the source of the field. This means that a ramscoop
>electric field of -10,000 electron volts for example will be stronger
>the the interstellar electric field strength for a radius of from
>100,000 kilometers to possibly millions of kilometers from the
>ramscoop.This ramscoop can be made of a lightweight material such as
>aluminium metal in the form of a grid or screen. a mere ten kilowatts of
>electricity could place a -10,000 volt elecric charge on the aluminium
>screen to attract interstellar protons into the engine.
> These interstellar protons would then be used as reaction mass in ion
>or plasma rocket engines. These electric engines would accelerate the
>protons into a high velocity exchaust jet which would propell the
>starship. A beam of protons if accelerated through a a one million volt
>electrostic field inside of an ion engine would obtain a velocity of
>10,000 to 15000 kilometers pers second. This results in an ion engine
>specific impulse of 1000,000 to 1,500,000 seconds. A plasma engine would
>heat the the ionized hydrogen propellant collected by the ramscoop to
>fusion range temperatures (10,000,000 degrees c to 100, 000, 000
>degrees c ) , with a high energy elecric arc or laser beam . Then the
>plasma would be exchausted through an elecromagnetic nozzle to generate
>thrust to propell the starship. Inside this superconducting
>elecromagnetic nozzle, electromagnetic body forces will also provide an
>additional acceleration to the plasma via the lorentz force. The plasma
>engine would have an exchaust velocity of 1000 to 10,000 kilometers per
>second. This means a specific impulse of 100,000 to 1000,000 seconds.
> The rate of the acceleration of this starship is determined by the
>thrust to mass ratio of its ion or plasma engines. The velocity of this
>starship is determined acording to acceleration x time. The thrust of
>the ion or plasma drive is determined according to the exchaust velocity
>of the engines x the amount of reaction mass provide per second by the
>ramscoops. The acceleration of this starship would probably be from 10
>(-3) gs to 10 (-2)gs. This starship might be able to reach alpha
>centauri in a voyage of from 40 to 100 years. This means that the vessel
>would need to be either a generation ship or a sleeper ship. The sleeper
>technique could be used only if a medically safe method of placing
>people in suspended animation could be found. For robot starships
>however the time factor would not matter that much. This starship could
>obtain a velocity in space flight of from five to ten percent of the
>speed of light. If you wish to respond to this email message from me ,
>my e mail address is firstname.lastname@example.org
True that would work, but as you noticed the performance is rather low.
Basically we decided their was so little to scoop up in interstellar space,
you'ld do better to just carry extra reaction mass and save the trouble of
the ramscoop. Effectivly cruder systems worked much better.
Note the systems we were considering had far higher speed (possibly over 40%
of light speed for the mixed fusion systems, possibly up to lightspeed for
more difficult pure microwave sail craft), allowing travel to the nearest
stars in a bit over a decade. Round trip in under 30 years.
Thanks for your interest in our web site. Hope you found it interesting.