Question

A satellite is in a circular parking orbit with an altitude of 200 km. Using a one-tangent burn, it is to be transferred to geosynchronous altitude using a transfer ellipse with a semi-major axis of 30,000 km. Calculate the total required velocity change and the time required to complete the transfer

Answer 1

spacecraft's engine ejects mass at a rate of 30 kg/s with an exhaust velocity

of 3,100 m/s. The pressure at the nozzle exit is 5 kPa and the exit area is

0.7 m2. What is the thrust of the engine in a vacuum?

SOLUTION,

Given: q = 30 kg/s

Ve = 3,100 m/s

Ae = 0.7 m2

Pe = 5 kPa = 5,000 N/m2

Pa = 0

Equation (1.6),

F = q × Ve + (Pe - Pa) × Ae

F = 30 × 3,100 + (5,000 - 0) × 0.7

F = 96,500 N