Today is set to be a pretty emotional day, as ESA’s wildly successful Rosetta mission comes to an end – with a gentle bang.
Rosetta launched on March 2, 2004, before entering orbit around Comet 67P/Churyumov-Gerasimenko on August 6, 2014. Since then, it’s been studying the comet in earnest, and it also released the Philae lander onto the surface in November 2014, which was recently pronounced dead.
All the action is going to be streamed live online tomorrow, so you’ll be able to see views from mission control as scientists bid farewell. The spacecraft will also be performing some last gasp science, too.
Beginning yesterday at 4.50pm EDT (9.50pm BST), Rosetta started its final maneuver that will set it on a collision course with the comet. This descent began from an altitude of 19 kilometers (12 miles) above the surface.
Then, today at 6.40am EDT (11.40am BST), plus or minus 20 minutes, Rosetta is scheduled to impact the comet at walking speed (confirmation is expected 40 minutes later, owing to the comet’s distance from Earth).
It’s unclear how well the spacecraft will survive the impact, but regardless, we will not hear from it again. Being unable to direct its antenna towards Earth to communicate, it will instead turn off all its systems following touchdown, going forever silent.
That’s not to say the grand finale itself won’t be exciting. Rosetta will be transmitting all the way down, including images, which will be shared throughout the day.
And the mission’s legacy will live long into the future. Already, Rosetta has increased our understanding of comets like never before. Among its discoveries, it has found oxygen in the gas cloud around the comet, discovered the ingredients for life, and also found that Earth’s water may not have been delivered by comets.
With no other missions to comets planned in the near-future, this will be the last glimpse we get up close of one of these icy rocks for quite some time. But the science will continue, with reams of data from Rosetta still to be studied and analyzed over the next few years.
For now, though, it's time to bid farewell. So long Rosetta, we hardly knew ye.