Dean R. Chapman


Dean R. Chapman died of cancer at his home on October 4, 1995. Dean began his career at Ames Aeronautical Laboratory in 1948. As director of Astronautics in the 1970s, his administrative responsibilities involved programs such as shuttle thermal protection and the Pioneer Venus Probe/Orbiter mission.

The research that challenged Dean the most was his work on the origin of tektites. This began with a visit to the British Museum where he saw button-shaped australites that had shapes similar to those of objects produced by experiments at an Ames Research Center wind tunnel while researching the problem of protecting spacecraft from severe aerodynamic heating in hypervelocity flight. Dean successfully reproduced tektite shapes using an arcjet, which simulated atmospheric entry conditions. During his research, Dean amassed a large tektite collection, which is now at the Smithsonian Museum of Natural History.

Dean and co-workers determined the density and specific gravity of ~47,000 tektites and had 530 tektites analyzed for major- and trace-element compositions. He defined compositional trends within the Australasian strewn field and his compositional classification of Australasian tektites is still used today.

During the 1960s, Dean and colleagues published several papers dealing with his proposal that tektites were produced by impact cratering on the Moon. He stopped work on the tektite problem just as the Apollo program began. Samples returned by the Apollo astronauts soon proved, to most researchers, that tektites did not come from the Moon and today most investigators believe that tektites were formed by terrestrial impact.

Dean joined the faculty of Stanford University in 1980. He retired around 1994 and once again became interested in the tektite problem due to the discovery of a perfectly preserved ablated tektite recovered from the Central Indian Ocean. He is co-author of a paper that discusses the significance of this tektite. The paper has been accepted for publication in the journal Meteoritics.

--Billy P. Glass