Orbital effects on satellite’s performance

·         Doppler shift in frequency due to relative motion between the satellite and the point on the earth’s surface is the prime concern in the low orbit satellite and is to be taken care of for the establishment of the perfect communication link. Doppler can be given as

·         fR, fT are transmitted and received frequencies respectively, VT is the component of transmitter velocity directed towards the receiver and vp is the phase velocity of light.

·         The Doppler is not available in the downlink, but it affects the uplink if unchecked. The Doppler is not available with a geostationary satellite since there is no relative motion between the earth station and the satellite.

Range Variations

            With the best station-keeping system available, the position of a geostationary satellite with respect to the earth exhibits cyclic variations daily. The resulting range variations have a negligible effect on the power equations, an effect on the roundtrip delay. For this, there is a large guard time in the TDMA systems. So, the TDMA system ceaselessly monitors the vary and adjusts the burst temporal arrangement consequently.

Eclipse

            A satellite is claimed to be in eclipse once the world blocks the solar power to star panels of the satellite once the 3 are available to the line. As discussed in the previous section, the eclipse occurs twice a year around the equinox. Fig. 1 shows the eclipse time per day during the period of eclipse.

            The solar eclipse caused by the moon to the geostationary satellite occurs when the moon moves to the front of the sun. The eclipse occurs irregularly in time of duration and depth. In general, the eclipse might occur twice at intervals of 24hr. Eclipse might vary from a couple of minutes to over 2 hours at intervals a median length of concerning forty minutes. Compared to an earth-solar eclipse, the number of moon-solar eclipse range from zero to four with an average of two per year. It is worthwhile to note that if the moon-solar eclipse of long duration occurs just before or just after the earth’s solar-eclipse, the satellite should face special issues in reference to battery recharging and spacecraft thermal reliability. In order to cope with the solar battery problems during the eclipse, an energy reserve is provided with the satellite.

            During the full eclipse, a satellite receives no power from sun and it must operate entirely from batteries. This can scale back the out there power considerably because the spacecraft nears the ends of its life and it may necessitate shutting down some of the transponders during the eclipse period. Spacecraft designers must guard harmful transients as solar power fluctuates sharply at the beginning and end of an eclipse. There is a possibility of having the primary power failure and so, the probability that a primary power supply failure is much more during eclipse rather than any other operations like deployment.

Sun-transit Outage

The overall receiver noise will rise significantly to affect the communications when the sun passes through the beam of an earth station antenna. This effect is predictable and can cause an outage for as much as 10 min a day for several days and for about 0.02% an average year. The receiving earth station must wait till the sun moves out of the main lobe of the antenna. This occurs during the day time, where the traffic is at its peak and forces the operator to hire some other alternative channels for the uninterrupted communication link.

What do you mean by Two Body problem in Orbital mechanics? Use the necessary Diagram.

Part 1:

            In classical mechanics, the 2-body problem is to determine the motion of 2 point particles that interact only with one another. Common examples include a satellite orbiting a planet, a planet orbiting a star, two stars orbiting each other (a binary orbit), and a classical electron orbiting an automatic nucleus (although to resolve the electron/nucleus 2-body system properly, a quantum mechanical approach should be used).

            The 2-body problem will be re-formulated as two 1-body problems, a trivial one and one that involves determination for the motion of one particle in an external potential. Since many 1-body problems can be solved exactly; the corresponding 2-body problem can also be solved. By contrast, the three-body problem (and, additional typically, the n-body problem for n>=3) can’t be resolved in terms of initial integrals, except in special cases.

Part 2:

Let x1 and x2 be the vector positions of the 2 bodies, and m1 and m2 be their masses. The goal is to see the trajectories x1(t) and x2(t) for all times t, given the initial positions x1(t=0) and x2(t=0) and also the initial velocities v1(t=0) and v2(t=0).

When applied to the 2 masses, Newton’s second law states that

F12(x1, x2) = m1x1

F21(x1, x2) = m2x2

Where F12 is the force on mass 1due to its interactions with mass 2, and F21 is the force on mass 2 due to its interaction with mass 1. The two dots on top of the x position vectors denote their second