A rocket is fired ‘vertically’ from the surface of mars with a speed of 2 km s–1. If 20% of its initial energy is lost due to martian atmospheric resistance, how far will the rocket go from the surface of mars before returning to it ? Mass of mars = `6.4×10^(23)` kg; radius of mars = 3395 km; G = G = `6.67 × 10^(–11)` N `m^2` `kg^(–2)`.