Warp Drives are solutions of the Einstein Field Equations that allows superluminal travel within the framework of General Relativity. There are at the present moment two known solutions: The Alcubierre warp drive discovered in $1994$ and the Natario warp drive discovered in $2001$. The major drawback concerning warp drives is the huge amount of negative energy able to sustain the warp bubble.In order to perform an interstellar space travel to a "nearby" star at $20$ light-years away in a reasonable amount of time a ship must attain a speed of about $200$ times faster than light.However the negative energy density at such a speed is directly proportional to the factor $10^{48}$ which is $1.000.000.000.000.000.000.000.000$ times bigger in magnitude than the mass of the planet Earth!! Although the energy conditions of General Relativity forbids the existence of negative energy the Casimir Effect first predicted by Casimir in $1948$ and verified experimentally by Lamoreaux in $1997$ allows sub-microscopical amounts of it. Lamoreaux obtained experimentally negative energy densities of $10^{-4} \frac{Joules}{Meter^{3}}$.This is an extremely small value $10^{20}$ times lighter than the ones of a body of $1$ kilogram in a cubic meter of space or better:$100.000.000.000.000.000.000$ times lighter than the ones of a body of $1$ kilogram in a cubic meter of space. We introduce in this work a shape function that will low the negative energy density requirements in the Natario warp drive from $10^{48} \frac{Joules}{Meter^{3}}$ to $10^{-7} \frac{Joules}{Meter^{3}}$ a result $1000$ times lighter than the ones obtained by Lamoreaux proving that the Casimir Effect can generate and sustain a Natario warp drive spacetime.We also discuss other warp drive drawbacks:collisions with hazardous interstellar matter(asteroids or comets) that may happen in a real interstellar travel and Horizons(causally disconnected portions of spacetime).