Orbit Xplorer Review

The first thing I found out as I was running some simulations is that if the simulation speed is too high, the program calculates the orbits extremely inaccurately as is visible in this picture (top) of the orbits of the planets in our solar system (The lines are the orbits of the planets).

I ran the simulation over night at a much slower speed and after 15 hours the simulation was predicting the orbits of the planets more accurately as in the bottom picture. The only problem was that the orbits were circles, instead of elliptical. I explain the reason for this problem below.

Next I ran a simulation of the planetary system orbiting 55 Cancri with the two known planets. The orbits were stable, with the planet closest to 55 Cancri causing the star to make a small orbit of its own.

I then ran the same simulation with the third calculated planet, and the system was still stable with the third planet having a slightly elliptical and off center orbit. (You can find more information about the planetary system around 55 Cancri here:

» Newfound Planetary System Has 'Hometown' Look.

Click for larger view

One of the features I found very interesting, is the “Activities”. These consist of 28 pre-programmed simulations that show such things as a rocket launch, gravity assist, and double star systems. Some features are of less obvious use, for example the “Catch that Satellite” and “Two colliding stars.” The help file is adequate, but could use more, maybe something that will tell you why something happened in a simulation.

I noticed three problems other than the accuracy. Sometimes when you zoom in to the maximum setting, the program will shut down. When I ran the simulation overnight, I could not operate the zoom with the short-cut keys.

Strangely, the Sun, planets, and our moon were pre-programmed into the program to use in your own simulations - yet it neglected to include all of the orbital data for them, which makes the program harder to use (such as setting up a simulation of our solar system). Other than this the program was error free.

Aimed at personal users and the educational market, this program is a good deal for the money, especially for schools. It requires only a little knowledge of astronomy and physics/math to run and understand the pre-programmed simulations. Creating your own simulations (such as extrasolar planetary systems) requires more skills, but any dedicated user should be able to figure it out.


A free version is available at http://www.ottisoft.com/orbit_x.htm.
The full version for a single user runs at $25, and the multiple user version (school premises only) is $89.

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