Orbital Mission Simulator

Understanding Orbital Mechanics

Orbital motion is not about flying upward. It is about falling sideways fast enough that the planet curves away beneath you. This idea was first explored by Isaac Newton when he imagined a cannonball fired from a mountain with increasing speed.

If the velocity is high enough, the object keeps missing the ground forever. That continuous fall around a planet is what we call an orbit.

The Physics Behind It

Gravity pulls objects toward a planet with a force proportional to the planet’s mass and inversely proportional to the square of the distance between them.

F = GMm / r²

In orbit, this gravitational pull constantly bends the spacecraft’s path, producing a curved trajectory around the planet.

Circular Orbit Velocity

For a stable circular orbit, a spacecraft must travel at a very specific speed determined by the mass of the planet and the distance from its center.

v = √(GM / r)

Around Earth, satellites in low orbit travel at roughly7.8 kilometers per second. That is fast enough to circle the planet every ninety minutes.

Hohmann Transfer Orbits

Moving between two circular orbits requires changing orbital energy. The most efficient way to do this is the Hohmann transfer.

The spacecraft performs two short engine burns:

• The first burn pushes the spacecraft into an elliptical transfer orbit.
• The spacecraft coasts along this ellipse toward the new altitude.
• The second burn circularizes the orbit at the destination altitude.

This maneuver minimizes fuel consumption, which is why it is widely used in satellite deployment and interplanetary missions.

What to Observe in the Simulator

• Start with a circular orbit and watch the spacecraft trace a stable path.
• Trigger the transfer burn to raise the opposite side of the orbit.
• Notice how the orbit becomes elliptical.
• Observe how the spacecraft climbs to a higher altitude.

These are the same principles used to move satellites between Earth orbits and even to send spacecraft to other planets.