Helpful Hints

Satellite Calculator Help File

This program allows you to apply astronomical formulas to all of the moons of every planet in our Solar System at the same time. We define Regular Satellites as those are close to their planet and greater than 35km in radius; Irregular Satellites are typically small and far away. There is some overlap in the two lists.

In the space provided enter equations using the constants and planetary variables in the three tables below or you can select an equation from the menu. Remember the box must be empty if you are using the menu.

Once you hit submit, your answers will be displayed in MKS units (meters, kilograms, and seconds) and degrees, unless you multiply them by one of the unit changing variables like "m2AU" which converts meters to AU.

Sample Equations:

For Escape Velocity enter: sqrt(2*G*M/R)

To change Orbital Period from seconds to hours enter: Po*s2hr

DEFINITIONS
Satellite Mass: The Mass of a satellite is the total amount of matter contained in the satellite. The units of mass are kilograms.

Satellite Radius: The Radius of a satellite is the distance from its center to its edge. The radius is given in units of meters.

Satellite Density: The Density of a satellite is the ratio of a satellite's mass to its volume. The units of density are kilograms per meters cubed.

Surface Gravity: The Surface Gravity is the acceleration due to gravity on the surface of the satellite. The units of surface gravity are meters per seconds squared.

Escape Velocity: The Escape Velocity is the velocity a body needs to escape the gravity of the satellite and get out into space. The units of escape velocity are meters per second.

Semimajor Axis: The Semimajor Axis is the longest diameter of the orbital ellipse. The units of semimajor axis are meters.

Orbit Eccentricity: The Eccentricity is how elliptical an orbit is. Eccentricity is unitless.

Orbit Inclination: The Inclination is how much a satellite's orbit is tilted with respect to the planet's orbital plane. The units of inclination are degrees.

Orbital Velocity: The Orbital Velocity of a satellite is how fast it orbits the planet. The units of orbital velocity are meters per second.

Orbital Period: The Orbital Period is the time it takes for a satellite to go once around the planet it orbits. The orbital period is given in seconds.

Hill Radius: The Hill Radius is the distance within which orbitting bodies around the satellite will have stable orbits. The units of the Hill radius are meters.

Planet Oblateness: The Oblateness of a planet is how much is has been flattened by its rotation. Oblateness is unitless.

Planet Tilt: The Tilt of a planet is the axial tilt with respect to the orbital plane. The units of tilt are degrees.

DEFINITIONS
Satellite Mass: The Mass of a satellite is the total amount of matter contained in the satellite. The units of mass are kilograms.
Satellite Radius: The Radius of a satellite is the distance from its center to its edge. The radius is given in units of meters.
Satellite Density: The Density of a satellite is the ratio of a satellite's mass to its volume. The units of density are kilograms per meters cubed.
Surface Gravity: The Surface Gravity is the acceleration due to gravity on the surface of the satellite. The units of surface gravity are meters per seconds squared.
Escape Velocity: The Escape Velocity is the velocity a body needs to escape the gravity of the satellite and get out into space. The units of escape velocity are meters per second.
Semimajor Axis: The Semimajor Axis is the longest diameter of the orbital ellipse. The units of semimajor axis are meters.
Orbit Eccentricity: The Eccentricity is how elliptical an orbit is. Eccentricity is unitless.
Orbit Inclination: The Inclination is how much a satellite's orbit is tilted with respect to the planet's orbital plane. The units of inclination are degrees.
Orbital Velocity: The Orbital Velocity of a satellite is how fast it orbits the planet. The units of orbital velocity are meters per second.
Orbital Period: The Orbital Period is the time it takes for a satellite to go once around the planet it orbits. The orbital period is given in seconds.
Hill Radius: The Hill Radius is the distance within which orbitting bodies around the satellite will have stable orbits. The units of the Hill radius are meters.
Planet Oblateness: The Oblateness of a planet is how much is has been flattened by its rotation. Oblateness is unitless.
Planet Tilt: The Tilt of a planet is the axial tilt with respect to the orbital plane. The units of tilt are degrees.

Advanced Functions:

J2 apsidal precession: dwdt

J2 nodal precession: dWdt

Solar nodal precession: dWSdt

Satellite Mean Motion: n

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