A deep-space probe's emergency power recovery systems are being evaluated. Engineers are comparing two methods of auxiliary energy storage to support the scientific instrumentation during a main reactor outage:
System P (Pneumatic Storage): Compressing gas in high-pressure tanks.
System Q (Electrochemical Storage): Charging high-density lithium-sulfur batteries.
Calculate the difference in the useful energy retrieved (in kJ\text{kJ}kJ) from 50 kg50\text{ kg}50 kg of storage mass between System Q and System P.