Who built the first viable launching pad?

The first viable launching pad was built by Colonel William Congreve, who is known for his contributions to the development of rocket technology in the early 19th century. Congreve's innovations included the design of cylindrical rockets that were launched from sturdy platforms, which significantly improved the stability and accuracy of rocket launches compared to prior methods. His work laid the groundwork for the future advancements in rocketry and launching technologies.

Other figures in the choices have made significant contributions to space and rocketry, but they are not specifically known for developing a viable launching pad. For example, Dr. Hermann Oberth contributed to the theoretical foundations of rocketry and space travel. Dr. Robert Goddard is often referred to as the father of modern rocketry due to his successful development of liquid-fueled rockets, while Konstantin Tsiolkovsky is seen as a pioneer in astronautics and theoretical propulsion concepts. However, none of them created an operational launching pad that matches the criteria set by Congreve's designs.