AEgIS is the acronym for Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy

In ancient greek aegis is a leather cloak, goatskin or a breastplate related to Zeus or Athena. The aegis is symbol of protection and power, rather than a military shield. Doing something "under someone's aegis" means acting under the protection of a powerful and knowledgeable source.

Athena's aegis looks like the skin of the huge serpent who guards the golden fleece
(Vatican Museum)

Mosaic of Alexander the Great bearing on his armor an image of the Gorgon (a terrifying creature) as an aegis
(Naples National Archaeological Museum).