If you ask almost any planetary scientist why she chose planetary science, she’ll likely say something along the lines of “I wanted to get my hands dirty!” The relative closeness of objects in our solar system makes them much easier to explore than our stellar neighbors, and technological advances have given planetary scientists the opportunity to truly touch other planets.
We now live in a world where, given enough time and money, we can visit any body in our solar system using spacecraft. These time and money constraints, however, have often forced planetary scientists to rely on serendipity to study comets.
Such was the first spacecraft encounter with a comet, when the International Cometary Explorer (ICE) flew through the tail of Comet Giacobini-Zinner in 1985. ICE wasn’t designed specifically for this purpose – in fact, it was sent into space to study the solar wind. ICE was actually the second incarnation of the International Sun/Earth Explorer 3 (ISEE-3) mission, which changed names when it changed course in order to intersect with the comet tail. Since then, many missions have capitalized on the opportunity to repurpose other probes to rendezvous with comets.
Of course, comets ...