June 10, 2016

Colloquium Speaker: Jeff Plescia

Jeffrey Plescia is a planetary scientist at the Johns Hopkins University, Applied Physics Laboratory, where he has worked since 2004. Prior to coming to APL, he worked at the U. S. Geological Survey, and before that at the California Institute of Technology Jet Propulsion Laboratory.  During his tenure at the Jet Propulsion Lab, he served two temporary assignments to NASA Headquarters as the Planetary Geology and Geophysics Program manager and as part of the Mars planning effort.

He received his Ph.D. (1985) and M.S. (1981) in Geophysics from the University of Southern California.

His research interests include the geology of Moon and Mars and terrestrial impact cratering. He was part of the international team that conducted the CDP-USGS deep drilling project at the Chesapeake Bay Crater. He has conducted field investigations at impact sites in the US, Canada and Australia. He is currently working with the imaging experiment on the NASA Lunar Reconnaissance Orbiter and conducted the search for US and Soviet robotic spacecraft on the lunar surface.

Colloquium Topic: Lost Landers – Unsolved Mysteries

Beginning in 1959 the Soviet Union launched a series of robotic missions to the Moon with the ultimate goal of sending humans to the surface. The Soviet missions included flybys, orbiters, landers, rovers, and sample returns. Zond 3 was the first mission to observe the far side of the Moon. As spacecraft tracking was in its infancy, the locations of spacecraft on the surface were poorly known. To make matters worse, several of the sample return missions were conducted during the lunar night, precluding the acquisition of images to understand the landing site. The Lunar Reconnaissance Orbiter, which entered lunar orbit in June 2009, began taking high resolution images of the surface to search for the Soviet (and American) landed spacecraft. Using high resolution images, we have discovered the locations of all but two of the Soviet spacecraft (Lunas 9 and 13). We have also discovered the reason why the Luna 23 sample return mission failed – it fell over.

The talk will discuss the search for the spacecraft, why we haven't been able to find Luna 9 and 13, and the implications of locating the landing sites.