{'fraction_non_alphanumeric': 0.009876543209876543, 'fraction_numerical': 0.0, 'mean_word_length': 5.286821705426356, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Propulsion by light: visions of the German pioneer Eugen Saenger

Although the laser was not yet invented Eugen Sanger, one of the most prominent German personalities in the early development of hypersonic flight and rocket technology suggested to use photons for the propulsion of spacecrafts in the fifties. In contrast to current schemes which are mostly aimed at laser induced ablation processes, Eugen Sanger started with the idea of using the radiation pressure itself for propulsion purposes. A review of his pioneering work in that area will be supported by numerous historical documents and personal remembrance showing his effort to promote unconventional ideas. The paper also emphasizes how some of the original concepts are being revisited and partly implemented by using today's laser technology.