Paolo Ferri, ESA’s Head of Mission Operations, expresses relief at the apparently successful release of Philae from the Rosetta mothership but the potential loss of a crucial touchdown system has caused increased anxiety about the landing.

The origin of of Comet 67P/Churyumov-Gerasimenko’s double-lobed form has been a key question since Rosetta first revealed its surprising shape in July 2014. By studying the layers of material seen all over the nucleus, scientists have shown that the shape arose from a low-speed collision between two fully fledged, separately formed comets.

This unusual view of 67P/Churyumov–Gerasimenko from Rosetta shows the darker side of the comet.