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In reply to Ben Franchuk's message
>> These proton rockets may have exchaust velocitys of 90 percent of light
>> speed or more.
>> Timothy J. Mayes
>Being a great fan of autodynamics ( but lacking great math skills )
>I wonder if .94 C is the best escape velocity. If I remember right from the
>web site, anything over about .75C the momentum of the particle decreases
>so thrust would be lost after that point. Other than that it sounds great.
A few questions:
- Escape velocity from what? The Earth, the Solar system....?
- "The best" regarding what parameter? Money, Fuel, Efficiency...?
You must be mistaken, about 0.75 c isn't a magic number where physics
breaks down. The momentum of a particle goes up when its velocity goes up,
even relativity agrees with that.
You might mean that the efficiency of the fuel usage decreases when the
exhaust velocity exceeds a certain speed. This is true for self-fuelled
designs, but that particular exhaust speed depends on the kind of fuel, the
efficiency of the engine and the final velocity of the starship.
For fusion designs this optimal exhaust velocity is rather low (but still
high compared to todays technology), usually less than 6% of the light speed.
Timothy (van der Linden)