Comet

Halley's Comet visits the earth every seventy-five years. Since the dawn of civilization, humans had believed comets were evil portents. In 1705, Edmond Halley liberated humanity from these primordial superstitions (or so it was thought), proving that Newtonian mechanics rather than the will of the gods brought comets into our celestial neighborhood. Despite this scientific advance, when Halley's Comet returned in 1910 and astronomers announced that our planet would pass through its poisonous tail, newspapers gleefully provoked a global hysteria that unfolded with tragic consequences.

One of the most basic laws of a web application is that the client, not the server, must initiate any communication between the two. There are a number of common–use cases where, ideally, the server would like to talk to the client—dashboards and monitoring apps, chat rooms and other collaborations, and progress reports on long–running processes.

In 2014, Rosetta became the first mission to orbit a comet and to deploy a lander onto its surface. This is the story of ESA’s pioneering comet explorer, following the mission from its initial inception to its historic touchdown.