Based Only on the Information Given in This Biography,discuss the Credibility

Based only on the information given in this biography,discuss the credibility and authority of the person described on each of the topics in the list that follows:
James A.Van Allen received a Ph.D.in physics from the University of Iowa in 1939.During World War II,he was a gunnery officer with the Pacific Fleet.After the war,he returned to the University of Iowa,where he became professor of physics and chairman of the Department of Physics and Astronomy.In 1958,during the mission of Explorer 1,the first successful U.S.Earth satellite,he discovered the radiation belts surrounding the Earth,that are named for him.He was the principal investigator for the space probe of Jupiter's radiation belts and one of the discoverers of the radiation belts of Saturn.He was chairman of the group that developed the Voyager and Galileo space missions and is currently principal investigator for the Pioneer 10 and Pioneer 11 projects.
a.the number of women employed by the National Aeronautics and Space Administration
b.the uses of satellites for national security purposes
c.the biological effects of ultraviolet radiation
d.the structure of comet tails
e.recent geological activity along faults in southern California
f.the impact of a manned space station on science and technology
We assume Van Allen's opinions on (f)would be very informed.He would also have great credibility on (d)and only slightly less on (c).His remarks on (b)would carry more weight than those of a layperson,but we would need further information about him before regarding him as an authority on (a)or (e).