I cant believe you are all so ignorant of the facts.
Its all very simple.
When the craft is in space there is no sound that can be heard externally because there is no air to conduct it. However, if the craft is using its engine to acclerate a tiny fraction of the energy of the exhaust can by conducted back through the nozzle, vibrating the craft and manifest as a faint noise inside the craft where there is (hopefully) some air. Most spacecraft do not run thier engines in space unless they are accelerating or changing orbit. This is because there is no drag (no air) and so the craft can maintain speed almost indefinitely without using any power (conservation of energy). Thus a satellite can remain in space for years without using its rocket motors other than for minor corrections.
Its also seems there is a serious misunderstanding here about heat energy of a spacecraft. The craft can dissipate some energy as heat by infra-red radiation which requires no air as it is an electromagnetic form of energy. However, (to contradist Bally Heck) it cannot conduct heat to its surroundings or convect heat whcich requires the presence of air. Incidentally, Bally Heck mentins the difference between the temperature of space and the craft. What are you on about. As a vacuum cannot contain any heat by defintion, there can be no conduction due to a difference in temperature. Radiation on the other hand is not affected by the difference in temperature between the two mediums, only by the radiating body's temerature.
Is that all clear now?