Io Volcano Observer (IVO) is a proposed robotic spacecraft that, if approved and launched, would orbit Jupiter and perform at least nine flybys of Jupiter's moon Io. IVO has been proposed to NASA by the University of Arizona and Johns Hopkins University's Applied Physics Laboratory as a Discovery-class mission in 2010 and 2015. IVO is also a contestant for the New Frontiers program. IVO was originally part of NASA's Discovery & Scout Mission Capability Expansion (DSMCE) concept-study program in 2009.