1573 Väisälä, provisional designation 1949 UA, is a stony Phocaea asteroid, slow rotator and suspected tumbler from the inner regions of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 27 October 1949, by Belgian astronomer Sylvain Arend at the Royal Observatory of Belgium in Uccle, Belgium.^[11] It was named for Finnish astronomer Yrjö Väisälä.^[2]

The stony S-type asteroid is a member of the Phocaea family (701), a group of asteroids with similar orbital characteristics.^[4] It orbits the Sun at a distance of 1.8–2.9 AU once every 3 years and 8 months (1,334 days). Its orbit has an eccentricity of 0.23 and an inclination of 25° with respect to the ecliptic.^[1] Väisälä's observation arc begins on the night following its official discovery observation at Uccle, as no precoveries were taken and no prior identifications were made.^[11]

This minor planet was named after Finnish astronomer, Yrjö Väisälä (1891–1971), a prolific discoverer of minor planets during the late 1930s and early 1940s.^[2] In addition, a second minor planet, 2804 Yrjö, was named in his honor by pioneering Finnish female astronomer Liisi Oterma, and the lunar crater Väisälä also bears his name. The official naming citation was published by the Minor Planet Center on 31 January 1962 (M.P.C. 2116).^[12]