The European Space Agency's Rosetta makes history tomorrow when it sends its Philae Lander down to the surface of Comet 67P/Churyumov-Gerasimenko. But Rosetta is hardly an overnight sensation. Let's look back at how we got here.
Rosetta started its journey in February, 2004 aboard an Ariane 5 rocket at the Guiana Space Center. However, officials delayed its launch due to heavy winds. During the delay, inspectors turned up a piece of detached foam and officials canceled Rosetta's launch, rescheduling it for the following month.
Rosetta finally made its journey to space on March 2, 2004, The ESA established contact with the probe shortly after its launch with instruments turned on and tested. By May, Rosetta returned its first scientific observations to Earth, sending images of a comet close to the sun. The spacecraft was then put in "cruise mode."
In September, 2005, a solar flare hit Rosetta. This damaged the star tracker subsystem, but was later fixed. In 2006, Rosetta's OSIRIS instrument studied asteroid 2867 Steins during a flyby, as well as collected data from the tail of comet 45P/Honda-Mrkos-Pajdusakova. In early 2007, the spacecraft flew close to Mars. Later that year, it did its second swing by Earth. The spacecraft continued onward and flew by asteroid 2867 Steins in late 2008. In 2009, it did its third swing by Earth, using the planet's gravitational pull to build up speed.
In 2010, Rosetta flew by asteroid 21 Lutetia. In June, 2011, Rosetta was put to sleep, its electronics shut off as it made its journey to Comet 67P. Rosetta woke up on January 20, 2014, sending a message to Earth that said "Hello World." The ESA spent the next few months updating Rosetta's communications software. In May, Rosetta started its first of 10 orbit correction maneuvers, aligning itself with Comet 67P. In August, Rosetta caught up to 67P and on Sept. 10, made history by becoming the first spacecraft to ever orbit a comet. As Rosetta sent back data about the comet, the ESA spent the next month determining landing spots on its surface, narrowing it down to five, and then deciding on one.
Tomorrow, Rosetta will travel slightly away from the comet, to just about 18 miles above its surface. Then it begins a dive towards it, to about 12 miles above it. The spacecraft will release its Philae Lander, shooting it at the comet. Once the lander comes into contact with the comet's surface, harpoons will attach it to the comet's surface, making history yet again.
Philae will send back unprecedented high-resolution images from the comet's surface, as well as collect data about the comet's composition. The hope is that our theories about how comets once carried life to Earth will be verified by discovering organic compounds within 67P's materials.
"ROSINA, the 'comet sniffer' on Rosetta, has detected a variety of molecules in the coma of 67P/C-G, including water, carbon monoxide, carbon dioxide, methane, and a few nitrogen or sulphur species," says the ESA's Rosetta blog. "Recently, also VIRTIS detected both water and carbon dioxide in the comet's coma, measuring their relative abundance".
The Philae Lander will separate from Rosetta around 09:03 GMT, with its touch down on the comet expected around 16:02 GMT. The ESA is streaming the event live from mission control at https://new.livestream.com/esa/cometlanding.
[Photo Credit: ESA/Rosetta/NavCam]
