Our topic for today is another rocketry concept:
Specific impulse (usually abbreviated
Isp). Basically, it's how efficient your rocket engine is. It's defined by how far each unit of fuel moves your rocket.
Here's the formula:
![Isp equation](http://wiki.kerbalspaceprogram.com/images/math/9/0/d/90d69d3f53b09f43a83a2e51064bec4c.png)
Where:
is the specific impulse in meters per second
the thrust in newtons
the fuel consumption in kg/s
So, Isp is how much thrust you get per unit of fuel.
If your Isp is higher, then you can get more
Delta-V with the same rocket. In the rocket equation,
![v_\text{e}](https://upload.wikimedia.org/math/a/4/4/a4428fdd20c2aad78733b5847efb8bd9.png)
is used instead of Isp, but the concepts are the same.