Whipple mission was a proposal for a space observatory in the NASA Discovery Program 2014 announcement of opportunity. It would orbit in a halo orbit around the Earth–Sun L2 and have a photometer that would try to detect Oort cloud and Kuiper belt objects (KBOs) by recording their transits of distant stars. It would be designed to detect objects out to 10,000 AU. Some of the mission goals included directly detecting the Oort cloud for the first time and determining the outer limit of the Kuiper belt. Whipple would be designed to detect objects as small as a kilometer (half a mile) across at a distance of 3,200 billion kilometers; 22,000 astronomical units (2×1012 mi). It would need a relatively wide field of view and fast recording cadence to capture transits that may last only seconds.