Scientists have speculated for centuries about comets. Why do the become visible on an irregular interval? Why does the tail always point away from our sun? What are comets made of? Are they balls of ice, or more like an asteroid?

Now NASA may finally get some concrete answers with a current mission that will land on a comet later this year!

Comet 67P/Churyumov-Gerasimenko is releasing the Earthly equivalent of two glasses of water into space every second. The observations were made by the Microwave Instrument for Rosetta Orbiter (MIRO), aboard the European Space Agency’s Rosetta spacecraft on June 6, 2014. The detection of water vapor has implications not only for cometary science, but also for mission planning, as the Rosetta team prepares the spacecraft to become the first ever to orbit a comet (planned for August), and the first to deploy a lander to its surface (planned for November 11).