Oleksandr Dmytrovych or Alexander Dmitrievich Zasyadko (Russian: Засядко, Александр Дмитриевич; Ukrainian: Засядько, Олександр Дмитрович) (1779 – 8 June [O.S. 27 May] 1837), was a Russian/Ukrainian gunner and specialist in rocketry, Lieutenant General (1829).
In 1797, Zasyadko graduated from the Artillery and Engineering School in Saint Petersburg (currently Mozhaysky Military Engineering-Space University). In 1799, he participated in the Italian campaign of the Russian army under the command of Aleksandr Suvorov, Russo-Turkish War of 1806-1812 and Patriotic War of 1812.
In 1815, Zasyadko began his work on creating military gunpowder rockets. He constructed rocket-launching platforms, which allowed to fire in salvos (6 rockets at a time), and gun-laying devices. Zasyadko elaborated a tactics for military use of rocket weaponry. In 1820, Zasyadko was appointed head of the Petersburg Armory, Okhtensky Powder Factory, pyrotechnic laboratory and the first Higher Artillery School in Russia. In 1827, Zasyadko was in charge of Artillery Headquarters of the Russian army and took part in the Russo-Turkish War of 1828-1829. He organized rocket production in a special rocket workshop and created the first rocket sub-unit in the Russian army.
In 1834, Zasyadko retired due to his illness. The crater Zasyadko on the far side of the Moon is named after him.