It is not rocket science

Origin

During the exhilarating and tense years of the mid-20th century's Space Race, the field of 'rocket science' became the ultimate benchmark for intellectual difficulty and complex problem-solving. As nations vied for supremacy in space, the engineers and scientists behind these ambitious projects were seen as dealing with the most profound and intricate challenges imaginable, their work far removed from everyday understanding. This public perception of rocket science as the peak of complexity soon gave birth to the idiom. When a task was genuinely simple, requiring little specialized knowledge or effort, people began to exclaim, 'It is not rocket science,' thereby contrasting its ease with the colossal mental demands of launching vehicles beyond Earth.