This page requires a JavaScript -capable browser. Instructions Enter full and dry rocket mass in some of the fields above, then press TAB or click Compute.
Specific impulse is in seconds.
It's the clearest measure of how hard a rocket has to work to change position. The diagram to the right is based on Figure 2.2 of this book, and indicates the delta-V needed to transfer among various orbits. You can use the radio buttons above to convert between specific impulse and exhaust velocity. But it can be applied to a great many models. For example, you could calculate the delta-V attainable by a baseball pitcher, throwing baseballs to change his orbit.