

NASA's NEXT engine  (Source:







Source: NASA

Comments     Threshold


Basic Physics?
By timothyd97402 on 1/1/2013 3:58:38 PM , Rating: 2
A very simplified version of how the math is done:

Assuming initial speed of zero, you accelerate constantly for the first half of your trip, finally reaching a speed of say 100,000 miles per hour. You flip over and then decelerate at a constant rate until at the end of your trip you reach a speed of zero.

Simple algebra here kids. Your average speed for the whole trip is half of your maximum speed at the halfway point or 50,000 miles per hour. What do they teach in school these days?

Now, this example is not entirely accurate as there is always the acceleration of gravity from the Sun and the Planets affecting your actual direction and speed (vector). Also since we are burning fuel during this hypothetical trip, the mass we are moving is less as time goes on, so we get more acceleration from a given amount of fuel at the end of the trip than we did at the beginning.

While the thrust, and therefore acceleration, of an Ion Drive is very low, there is little/no friction in space so your speed just continues to build up because an Ion Drive is so efficient that it can burn continuously on very little fuel. Great for long trips in open space, useless for getting off planet, haven't done the math for a trip to the moon.


Related Articles
