#
Simple Rocket Simulator

*This page requires a
Java-capable browser.*
This Java applet simulates 800 seconds of flight of a simple one-stage rocket.
The rocket is launched from the surface of Earth, straight up (i.e. along a
radius line), and fires its engines until its fuel is exhausted. Air drag is
taken into account via the standard Newtonian drag formula.

The default parameters implement a simple model of a
SpaceCub,
but you can
change them as needed to model other rockets (though the frontal cross-sectional
area is fixed at 3.6 m^2).

### Instructions

Enter the following values, then click "Compute". Time is plotted along the
X-axis in seconds; altitude is plotted on the Y-axis in kilometers.
Mass | total mass of ship plus fuel (kg) |
Fuel | mass of fuel (kg) |
CD | coefficient of drag (0-100%) |

Exh. Rate | mass expelled per sec (kg) |
Exh. Velocity | exhaust velocity (m/s) |

### Source Code

### Discussion

This is my first Java rocket simulator. The interface is crude and needs much
embellishment; in particular, I want to provide controls for varying the
environmental variables, and more control over the ship.
I believe that the simulation itself is accurate as far as it goes, but it
could go farther. First, I am not certain the drag formula is correct for
supersonic speeds; I am probably underestimating the drag under these
conditions. More importantly, one can never achieve orbit by thrusting straight
up. I need to angle the rocket and allow a circularizing burn, so that a proper
orbit can be attained.

Finally, the output is as crude as the input. The rocket modeler wants to
know not just position, but velocity, acceleration, etc. I will need to expand
my GraphPane class to handle multiple sets of data.

If you have any comments, questions, or suggestions, please write to me at
joe@strout.net.

http://www.strout.net/info/science/rocketsim/simplesim.html

Last Updated:
1/29/00
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