Luna 19 (a.k.a. Lunik 19) (E-8-LS series), was an uncrewed space mission of the Luna program. Luna 19 extended the systematic study of lunar gravitational fields and location of mascons (mass concentrations). It also studied the lunar radiation environment, the gamma-active lunar surface, and the solar wind. Photographic coverage via a television system was also obtained. Luna 19 was the first of the “advanced” lunar orbiters whose design was based upon the same Ye-8-class bus used for the lunar rovers and the sample collectors. For these orbiters, designated Ye-8LS, the basic “lander stage” was topped off by a wheelless Lunokhod-like frame that housed all scientific instrumentation in a pressurized container.

Wikipedia: https://en.wikipedia.org/wiki/Luna_19. Related NASA reference: https://nssdc.gsfc.nasa.gov/planetary/chronology.html#1971. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).