Mass ratio required for orbital inclination change

Figure 5.15 presents the weight ratio for the four propulsions systems described in Table 5.3 and the four hypersonic gliders indicated in the column headings. With the hypergolic propellant, the mass ratio quickly becomes impracticable. The curve was

Change in orbital angle (degrees)

Figure 5.15. Mass ratio requirements for orbital plane change.

Change in orbital angle (degrees)

Figure 5.15. Mass ratio requirements for orbital plane change.

terminated at a mass ratio of 10 and a 50-degree plane change. With a hydrogen/ oxygen rocket the same mass ratio permits an 85-degree plane change. Extending the time for the plane change by transitioning to an elliptical transfer orbit and executing the plane change at 19,323 nautical miles (35,786 km) GSO orbital altitude reduces the mass ratio to 6 at a 90-degree plane change. The solar electric and nuclear electric together with the aerodynamic plane change vehicles provide the only practicable mass ratios for an operational infrastructure. The mass ratios for a 90-degree orbital turn are between 11 and 5. The weight ratios for the 32-degree orbital plane change for the impulse turn are: 4.53 for the hypergolic engine, 2.62 for oxygen/hydrogen, 1.15 for solar electric and 1.05 for nuclear electric, as shown in Table 5.10. The acceleration specified for the chemical rocket powered OMV is 0.5 "g". For the electric thruster powered OMV the acceleration is 0.1 "g".

The gross weight of the plane change OMVs is straightforward, and the sizing program balances the propellant required versus the capacity of the propellant tank that determines OEW. The sized OMVs for each of the propulsion systems transporting a 5000-lb (2.268-ton) satellite given in Table 5.10. The gross weight for a single mission is:

Gross weight = WR(OEWomv + ^satellite)

Note that the operational empty weight (OEW) of the OMV is essentially constant. It is greater for the electric propulsion configurations because of the solar panels for the solar electric and radiators for the nuclear electric (see

Table 5.10. Sized OMV for 32-degree plane change at 200 km for a 2,268 kg satellite.

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Getting Started With Solar

Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

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