Help with object orbits

In the drawing above will try to make it easy to understand what i need. I do NOT need YOU to give me code that does what i need to, i want to figure the coding part myself. I would need help with the concept.

Ok so the black circle represents a sphere. To make it easier i will use planets as example. Let’s say the black circle is Earth. Assuming Earth’s tilt remains constant, how can i make an object rotate around it with a certain speed, at a certain angle?

You could have the orbiting object always face the sphere and then just have it move left/right.

If you want to eventually go for more realistic orbits, you just need your object to always move towards the sphere (rigidbody.velocity += Vector3 (sphere.transform.position - object.transform.position).normalized * speed), then give it an initial movement to the side so it won’t actually touch the planet.

Don’t know about realistic speed though, the object would have to accelerate as it gets closer to the sphere.