Launching a spacecraft into Earth orbit is a difficult job that involves multiple stages. This diagram illustrates the many steps needed to get NASA’s Wide-field Infrared Survey Explorer (WISE) satellite to its circular science orbit.
Astronomy: Roen Kelly after NASA
Astronautical engineers often say that the most difficult part of any space mission is getting into Earth orbit. It matters little if the orbit is circular or eccentric — both are difficult. The altitude is not a key factor.
