His primary research interests include space physics, planetary atmospheres, observations and models.
[1] Mendillo became a professor of astronomy at Boston University in 1985, where he presently works.
Mendillo leads a research group that has developed new imaging techniques for observations of emissions from the atmospheres of the Earth, other planets and moons.
[1] With the help of his research group, Mendillo led the discoveries of extraordinary large, tenuous atmospheres of sodium gas on Jupiter, on the Moon and in comet Hale–Bopp.
He is also known for his work on Active Experiments, the research technique of introducing known gaseous perturbations into space plasmas, observing the effects, and deriving the basic physical processes that govern the system.