Does a satellite halo orbit regularly around earth does a satellite in a low earth orbit moving faster than the satellite in the higher earth orbit?

Answer 1

I think there are two questions here.

Does a satellite in a halo orbit, orbit regularly around the Earth?

The answer is NO because a halo orbit is an orbit around the L1 Lagrange point which is an equilibrium point between the Earth and Sun. The L1 Lagrange point is about 1.5 million km from Earth and orbits the Sun in the same period as the Earth so is always directly between the Earth and Sun. Several space craft have been put in and L1 halo orbit the most notable being the SOHO solar observatory. This has the advantage over Earth orbit in that it is outside the Earths magnetosphere and the space craft can always see the Sun as the Earth does not get in the way.

Does a satellite in low Earth orbit move faster that one in a higher orbit?

YES. Orbits can be thought of in terms of throwing an object horizontally. As you know the object falls to ground at some point along its path. The faster you throw it the further it goes. If you threw it fast enough, and there was no atmosphere to slow it down, there is a point where the forward motion matches the downward motion so that the object never hits the ground but travels in an orbit. The gravitational force of a planet decreases according to the inverse square law. i.e. the force is 4 times weaker at a point twice the distance from the planet. So the forward motion required to achieve an orbit further out is less than that nearer to the planet.

The orbital velocity equation is:

V = (GM/r)1/2

GM is constant for a particular body e.g. Earth

So as r the orbit radius get larger the velocity V gets smaller.