The possibility of sending the "Cassini" spacecraft from Saturn to Uranus was evaluated during a mission extension planning phase in 2009, but was ultimately rejected in favour of destroying it in the Saturnian atmosphere. It would have taken about twenty years to get to the Uranian system after departing Saturn. A Uranus orbiter and probe was recommended by the 2013–2022 Planetary Science Decadal Survey published in 2011; the proposal envisages launch during 2020–2023 and a 13-year cruise to Uranus. A Uranus entry probe could use Pioneer Venus Multiprobe heritage and descend to 1–5 atmospheres. The ESA evaluated a "medium-class" mission called Uranus Pathfinder. A New Frontiers Uranus Orbiter has been evaluated and recommended in the study, "The Case for a Uranus Orbiter". Such a mission is aided by the ease with which a relatively big mass can be sent to the systemover 1500 kg with an Atlas 521 and 12-year journey. For more concepts see Proposed Uranus missions.