The Hub

For all you sci-fi nerds out there (like me), I've recently updated my Orbital Calculator software, which is available as a free download from my website (Windows only). Here is a list of its features:

Select a gravitational mass, then add the orbital parameters (perigee and apogee) and it will calculate the orbital characteristics for you in various different equivalences (e.g. average speed in mph, kph and m/s and orbital period in days, hours, minutes seconds).

Calculate distance from gravitational mass using only the orbital period
(this is great for finding geostationary orbits)

Calculate visual satellite footprint from altitude. Also determines:
% of visible surface
degrees spread of visible surface
distance from edge to edge of footprint taking into account planet curvature
surface area of footprint
max time the satellite is visible from a point on the ground along the satellite's path
time for one orbit (orbital period)

Calculate apparent age from orbit e.g. if the locals use the local year to determine their age, what physical age would they present?

You can add new gravitational masses and satellites, and even export them to share with friends (or import their data).

The program is portable, meaning you don't have to run it - you can run it from a USB stick if you like!

So, if you're nerdy like me and like to get things like orbits right, download it now and give it a try.

You can download it here:
http://philip-p-ide.uk/doku.php?id=blog:articles:software:orbital_calculator

If you want to calculate what the surface gravity on your planet is, you can do that on this online calculator:
http://philip-p-ide.uk/doku.php?id=blog:articles:software:surface_gravity_calc

edit - sorry, just realised I'd put up the local links to the site instead of the public one - all fixed now!