He also conducted a wide range of research at the crater, discovering impactite, iron-nickel spherules related to the impact and vaporization of the asteroid, and the presence of many features still unique to the crater, such as half-melted slugs of meteoric iron mixed with melted target rock.

[5] Nininger's extensive sampling and fieldwork in the 1930s and 40s contributed significantly to the scientific community's acceptance of the idea that Meteor Crater formed by the impact of an asteroid.

[6] Harvey Nininger believed that the crater should be nationalized, and in 1948, successfully petitioned the American Astronomical Society to pass a motion in support.

[7] To this day, Nininger is omitted from any display or reference at the privately owned museum located on the crater rim.

Fletcher Watson of Harvard University in his book Between The Planets (1941) writes that Nininger was accounting for half of all the meteorite discoveries in the world at that time.