This top-priority "flagship" mission is the US half of a joint NASA-European Space Agency mission that would launch two large rovers to Mars in 2018. The rovers would conduct detailed studies of rocks and soil to hunt specifically for environments that are – or could once have been – hospitable for life. In addition to on-site studies, the rovers would collect and store samples that could return to Earth on later missions. But the NRC panel said the US rover should be approved only if its $3.5 billion cost can be cut by $1 billion in FY 2015 dollars. If that can't be done, MAX-C should be postponed or canceled.