Watch Live: Historic Rosetta Comet Landing

Today is the day!

After a 10-year and 4-billion-mile journey, the European Space Agency’s Rosetta spacecraft will finally land a robotic probe on a comet.



The event can also be followed here with NASA commentary starting at 6 a.m. PST (9 a.m. EST).

The Rosetta spacecraft was launched in March 2004 and reached comet 67P/Churyumov-Gerasimenko last August, becoming the first spacecraft to orbit a comet. For the last couple months, Rosetta has been capturing images and surveying the surface of 67P/C-G.

The satellite will release its 220-pound lander Philae at 11:35 p.m. PST (2:35 a.m. EST). After floating from a height of 13 miles, the small probe is expected to touch down today at 7:35 a.m. PST (10:35 a.m. EST).

Image of the Philae spacecraft

Image of the Philae spacecraft

In keeping with the mission’s Egyptian theme, the landing site (formerly dubbed “J”) has been named Agilkia after an island on the Nile River. The ancient Egyptian temple complex of Philae was moved to Agilkia when the building of the Aswan dams last century threatened to flood the site. The Rosetta spacecraft was named after the Rosetta Stone.

After fixing itself onto the comet using harpoons and drills, the Philae lander will use its 16 instruments to study the composition of 67P/C-G.

As the comet gets closer to the Sun and heats up, it will also release gas and particles that have been trapped since the formation of our Solar System. The mission could provide answers about the origins of Earth’s water and life.

The Rosetta spacecraft will continue to study 67P/CG from orbit. The comet will make its closest pass to the Sun in August 2015.

This video from the Open University includes five common questions answered about the Rosetta landing: