The space agency is putting together plans to send a lander to Europa, one of Jupiter's moons and perhaps the most likely place to harbour extraterrestrial life anywhere near us. But first it will have to work out how it can actually land on a surface about which it knows next to nothing. The agency started seriously exploring the possibility by commissioning a report on the value of sending a lander onto the icy surface of the moon. That report has now arrived and Nasa is looking to explore its findings with the scientific community. The mission's work will be divided up into three goals. The first and most important will be the search for life, but the other two are to look at how habitable Europa might be, and to explore the possibility of future robotic exploration of the moon and its oceans. Scientists expect that Europa has a large saltwater ocean underneath the icy crust that we can see. That has twice as much water as the oceans on Earth do, scientists expect. Those circumstances and others have led scientists to conclude that Europe is probably one of the most likely places to find present-day life outside of Earth, and it is relatively close by. As such, scientists hope that the plan to send a life-detecting robot to the planet – the first time that has happened at Nasa since the Viking mission more than 40 years ago. But they also have to cope with the fact that the icy surface of the moon is almost entirely unknown, and that it has no atmosphere and so can't make use of things like a heat shield or parachutes. The lander is being prepared ready for after Nasa's solar-powered flyby of Europa is expected to launch in the early 2020s. That will be able to take a variety of high-definition images of the ocean and the icy shell that surrounds it, helping us learn more about the surface before sending a lander onto the planet.
