Ganymede (moon) and possibly a JAXA-led Jupiter Magnetospheric Orbiter. ESA's contribution faced funding competition from other ESA projects, but on 2 May 2012 the European part of the mission, renamed Jupiter Icy Moon Explorer (JUICE), obtained a L1 launch slot in 2022 with an Ariane 5 in the ESA's Cosmic Vision science programme. The spacecraft will orbit Ganymede and conduct multiple flyby investigations of Callisto and Europa. The Russian Space Research Institute is currently evaluating the Ganymede Lander (GL) mission, with emphasis on astrobiology. The Ganymede Lander would be a partner mission for JUpiter ICy moon Explorer (JUICE). If selected, it would
Titan (moon) in diameter, 1.06 times that of the planet Mercury, 1.48 that of the Moon, and 0.40 that of Earth. Before the arrival of "Voyager 1" in 1980, Titan was thought to be slightly larger than Ganymede (diameter ) and thus the largest moon in the Solar System; this was an overestimation caused by Titan's dense, opaque atmosphere, which extends many kilometres above its surface and increases its apparent diameter. Titan's diameter and mass (and thus its density) are similar to those of the Jovian moons Ganymede and Callisto. Based on its bulk density of 1.88 g/cm, Titan's composition is half