The space industry is changing dramatically. We produce quicker, smaller, and cheaper satellites. Most of the technologies created by traditional satellites can now be created with small satellites-for instance, telecommunications with mega constellations operating at LEO (Low Earth Orbit) that will connect the whole world, even some remote parts of the word. The emergence of small launchers dedicated to the small satellites is another example. All of these trends provide easy access to space. At Nitrexo, we are standardizing space thermal engineering. We developed new standard methods, techniques and processes to significantly reduce the time from building the thermal model to validating or implementing the thermal design of space products by up to 50%, while improving the quality and accuracy of the deliverables at the same time. We significantly reduce the cost, the development cycle of the space product, the risk of not meeting the deadline, the risk of predicting inaccurate results, and the risk of the malfunctioning of the device in space. This particular eBook should be very useful to space thermal engineers and anyone who is involved in designing space systems.