Sunday, May 01, 2016

The Story of Rossetta and Philae

So you are thinking who are these people and why should we be interested in their story. Well firstly, they are not people. Maybe that’s what makes this an interesting story.

Humans have always been fascinated by space. We have wondered about our own solar system, Galaxy, the Universe and are constantly looking to explore. With our curiosity and the technology that we now posses, we send missions to nearby objects.

Rossetta and Philae were sent on one such mission to the Comet 67P a.k.a Churyumov–Gerasimenko. Rosetta being the spacecraft that would make the journey to the comet and orbit around it; and Philae being the probe that would land on this comet. The plan was for Rosetta to carry Philae near the comet, and drop it such that it lands at the desired site on 67P. Then Philae could do some science on the surface of this comet and communicate with Rosetta, which in turn would communicate back to earth. This is the first mission to ever land a probe on a comet.

Smaller objects like comets and asteroids are interesting bodies, as they give us insight to the origins of our solar system; and possibly, even answer key questions to origins of life.

This mission started in 1996 and the launch spacecraft was on March 2004, and Philae was able to land on Comet 67P on November 2014. That’s right, this trip took a decade. It wasn’t a linear trip from Earth to 67P. On its way, Rosetta had to perform few gravity assist flyby’s; one with Mars and rest with couple of asteroids. Their journey itself is epic, and highlights the amount of effort it takes for space travel.

So on reaching closer to Comet 67P, Rosetta (carrying Philae with it) started orbiting the comet for few days to align it to make the drop. Keep in mind that, Comet 67P travels at 135,000 Km / hr. Eventually, Rosetta had to let go of Philae so it could land. However things do go wrong, and Philae was not able to secure itself to the original site as planned on the comet. In fact, due to 67P’s speed and the drop velocity of the probe, Philae bounced 4 times on the surface and landed on the side that was facing away from the Sun. Damaged by the landing impact and unable to charge its solar powered batteries, Philae did send back signals and data it could collect from 67P until its primary batteries lasted, and then went into silent-hibernation, unable to communicate with Rosetta.

Although they were just a spacecraft and a probe, but they had been together for a decade, making a journey into the unknown, and in the very next moment there was total silence, no contact whatsoever. Can imagine how that would feel if they were real people.
How would the scientists who worked on this mission have felt?
So there it was, Rosetta kept orbiting Comet 67P, searching for signs of Philae. Those working on this mission had concluded that Philae would never contact back, mainly due to its impact upon landing. However, few months later, in June 2015, Philae did make contact with Rosetta, as it faced the sun and charged its batteries. There were only 8 intermittent contacts though from June to July, before Philae finally stopped communicating.

And during its time of activity, Philae was able to do some science and found 16 organic compounds, few of them being acetamide, acetone, methyl isocyanate and proionaldehyde. Out of which the last one is a compound found in our DNA. There were also traces of molecular oxygen (which is very rare to find in space) and heavy water (has isotope of Hydrogen i.e Deuterium).

After sending all these interesting information Philae went silent and hasn’t spoken since.  Rosetta is still orbiting Comet 67P from a distance of 170 to 200 km from its surface. This is how the Comet 67 looks when viewed by Rosetta; or click here

Well the mission funding will be over soon, and the question is what should be done with Rosetta. The plan for now is, it will continue to orbit 67P and gather information. And soon, for its end of life, would be made to land on the comet; which wasn’t the original part of the plan. Things are being worked out as to how to make a soft landing and not crash it.

So the final resting place for Rosetta would be where Philae is, on the surface of Comet 67P. Who knows, how the re-union would be.

This is why I love Astronomy. There are stories, there is wonder and there are possibilities. It’s one kind of poetry.

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