Oort cloud
Whipple was a proposed space observatory in the NASA Discovery Program. The observatory would try to search for objects in the Kuiper belt and the theorized Oort cloud by conducting blind occultation observations. Although the Oort cloud was hypothized in the 1950s, it has not yet been directly observed. The mission would attempt to detect Oort cloud objects by scanning for brief moments where the objects would block the light of background stars.