A space agency is considering two alternative plans to relocate a satellite from its…
PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A space agency is considering two alternative plans to relocate a 750kg satellite from its present circular orbit of radius 8.0×106m to a final circular orbit of radius 3.2×107m.
Plan A: Perform a single direct boost from the initial to the final orbit.
Plan B: First shift the satellite to an intermediate circular orbit of radius 1.8×107m, and after stabilising there, perform a second boost to the final orbit.
Assume Earth’s gravitational parameter GME=3.986×1014m3s−2.
(i) For Plan A, calculate the total external work required.
(ii) For Plan B, calculate separately the work required for the first and second boosts and hence the total work.
(iii) Compare the results of the two plans and comment on which plan is energetically more economical.
(iv) State one practical reason, other than energy economy, why mission planners might still choose the less economical plan.