Touchdown Rosetta: How ESA Will Maneuver the Spacecraft for the Grand Finale

Rosetta's "collision maneuver" will be executed on Sept. 30 and it will mark the "end of an odyssey."

"Rosetta is set to complete its historic mission in a controlled descent to the surface of its comet on 30 September, with the end of mission confirmation predicted to be within 20 minutes of 11:20 GMT," an ESA official said in a statement.

The comet-chaser Rosetta is a project of the European Space Agency (ESA) sent to observe comet 67P. The rendezvous with the comet occurred in August 2014, where the Philae lander was successfully sent to the comet using Rosetta. Two years after successfully gathering scientific data about comets, Rosetta will perform its final touchdown.

ESA engineers will switch off Rosetta's engine, which will cause the spacecraft to crash to its death on the surface of comet 67P.  The maneuver will start on the night of Sept. 29 and will last until Sept. 30. A calculated engine burn will devoid Rosetta of orbital energy, without it the spacecraft will free-fall to the comet for 14 to 15 hours in a drop of about 20 kilometers, according to The Guardian.

The free fall descent would be at the speed of about 30 centimeter per second; however, as the spacecraft goes near the comet, it will be drawn to the gravitational force causing it to drop a little faster. Rosetta's touchdown would not be as catastrophic since it is expected to impact at the same speed as the Philae lander. The difference is that Rosetta is not designed like Philae, so without an anchoring system, there is a big chance that the spacecraft might "tumble," this means there is very little chance for Rosetta to survive the impact.

But Rosetta's death will be worth it until the end. ESA decided to end the mission with a crash so the spacecraft won't add up to the existing space debris and also, until the time of the crash Rosetta will still be able to beam back science that will allow experts to take a closer look at the comet. Rosetta's onboard camera will be switched on during the whole duration of the descent to observe the landing site where an identified gas and dust emitting pit exists.

Due to transmission concerns between Rosetta and base, the confirmation might take about 40 minutes after the actual impact.  Rosetta's grand finale can be seen via live stream at Rosetta's official website.