It was a somber moment for those at the European Space Agency on Sept. 30 when the Rosetta mission finally came to an end as the agency intentionally crash-landed the orbiter into comet 67P/Churyumov-Gerasimenko.
The Rosetta mission had been one that gripped the attention of those at the agency and science enthusiasts alike ever since it began in 2004, carrying 11 scientific experiments and a small lander named Philae in tow.
Since then, it managed to accomplish an assortment of amazing feats, such as going past Mars and two asteroids, becoming the first spacecraft to orbit a comet, escorting the object around the sun and then deploying a lander to the comet's surface, as well as discovering what happened to the Philae lander after it went "missing."
With little energy reserves left as it moved further away from the sun, the Rosetta spacecraft given the final command on Sept. 29 to crash-land on the comet. The European Space Operations Centre received Rosetta's last signal on Sept. 30 at 1:19 p.m. local time (7:19 a.m. EDT), which confirmed the crash. The space probe snapped high-resolution images and analyzed gas and dust on the way down, putting an end to a mission that began 12.5 years ago.
And now that it's over, a new important question raises its head: What's next?
As Mark McCaughrean, ESA's senior science advisor noted, the Rosetta mission has set such a high bar that careful considerations will need to be taken when looking at which comet missions to move forward with in the future.
"The big question is: what do you do for an encore? Do you go and grab some material and bring it back to Earth - [what we call] sample-return. That's very expensive, but it could be a big international collaboration," said McCaughrean.
As far as comet missions go, there are two smaller comet proposals the ESA will be looking at next week: Castalia and Core (Comet Rendezvous Explorer).
Castalia would send a spacecraft to the asteroid belt between Mars and Jupiter to study an object that shows very comet-like behavior. Meanwhile, Core would attempt to put a lander on another comet. However, unlike Philae, whose landing didn't go quite as planned, this one would intentionally hop from place to place in order to study the comet's composition.
While both of these are simply proposals and can ultimately be shot down, there are several missions that are confirmed to begin in the next few years.
The first of these focuses on what many other space agencies have been seriously looking at recently: Mars. In the ESA's case, it will attempt to put a small probe called Schiaparelli on the surface of the red planet in a couple of weeks. This, however, is merely a demonstrator of what's to come in 2021: the landing of ExoMars.
In addition, there's the BepiColombo mission to orbit Mercury in 2018, as well as the JUICE (JUpiter ICy moons Explorer) mission to Jupiter and its various moons in 2022.
Lastly, there's the Solar Orbiter satellite that will begin its mission to venture extremely close to the sun in 2018.
So, yes, the Rosetta mission might be over and done with, but the ESA still has plenty on its plate for many years to come. However, the real question is whether these will be as successful as the Rosetta mission before them.
