Thursday, 20 November 2014

The Rosetta Mission

by Reetobrata Chatterjee




This aptly sums up the feat of engineering, physics and maths needed to complete this extraordinary mission. What was previously a figment of science fiction has finally become a reality. The comet in question is called by the rather catchy name “67P Churyumov–Gerasimenko” or just "67P" to its friends. It was first discovered in 1969, by some Soviet astronomers, which may account for the slightly unusual name. It’s usually located between the orbits of Earth and Jupiter, between 800 million to 186 million kilometres from the sun.

When the spacecraft successfully landed on the comet (which is the size of a small village), the comet was travelling at close to 135,000 km/hr (about 84,000 mph for those not metrically inclined). To put this into perspective, if the comet was travelling around the Earth, it would take less than 2 seconds to complete a full orbit of the earth!

Now that I’m done regurgitating facts about some random comet of no particular significance, let’s begin the story of the Rosetta mission.

The beginning of the writing of history

The Rosetta spacecraft’s journey begins in the small town of Darmstadt in West Germany in the year 1993, November to be exact. That’s when the European Space Agency (ESA) commissioned the project, a revolutionary idea at the time and still is now. It had never been attempted before partly because of the erratic and difficult-to-predict orbits of comets, asteroids and other “small” interstellar objects. However, the scientists and astronomers ploughed on regardless, unfazed by the difficulty of the task they had set out to accomplish. I am, of course, dramatizing the events, because I think the ACTUAL beginning of the mission was more formal, methodical and therefore, boring.

The aim of the project was to land a robot-probe on the comet and make various measurements. The initial comet, with the equally catchy name “46P Wirtanen”, was different to the one the probe finally ended up (67P) on because there were some technical difficulties (as one might expect on a project of this scale) which caused the scientists to change targets. The probe was going to provide scientists with feedback about the big questions. Not the philosophical ones discussing the existence of God, the afterlife and so on, but the more achievable and realistic ones about the beginning of our solar system, and maybe even clues about how life started on Earth.

The journey

It would be relatively nice and simple if people (or probes) could hop into a spacecraft and ride towards a comet. Alas, the reality isn’t that simple, since it is incredibly difficult and energy intensive (not to mention physically impossible with the current technology) to achieve this; the scientists had to use lots of clever maths to figure out exactly where the comet was going to be 10 years after the launch of the spacecraft. That’s right - in order to get to the comet many millions of kilometres away from Earth, the journey took TEN years. A simple journey wouldn’t have taken this long, but the trajectory the spacecraft was on involved orbiting both Earth and Mars, in order to alleviate the stress on the engines of Rosetta. In the end, the cumulative distance of the journey was 6.4 BILLION kilometres. It would take LIGHT six hours to travel this distance!

The big day

As you might expect, the scientists who had pioneered this journey were slightly excited that their project was coming to successful fruition, one of the more unorthodox manners of expressing this was demonstrated by Britain’s own Dr Matt Taylor. Even before the spacecraft had landed on the moon, to show his faith, he got a tattoo of the very scene!

The project had received a big influx in media attention (as it should) as it neared completion including prime coverage on the BBC as well as most major newspapers. How successful was the crucial part, the landing?

Meh.


It took the probe three tries to successfully land, which is not actually that bad, considering it was the first mission of its kind. The probe was equipped with German-made harpoons, which paradoxically didn’t detach. This caused the probe to briefly bounce off the surface of the comet, not something you want to be doing with a billion dollar probe. It was a tense moment as it finally landed, and a whole room in West Germany filled with sighs of relief and shouts of excitement.



The (slightly) sad ending

On the 14th November, 2014, communication to the probe was lost, simply because the probe had run out of battery. What a rookie mistake by the scientists, forgetting to charge that battery before the journey! On a more serious note, the primary observations had already been received by the space probe and only some were missed by the lack of communication.

But there is hope!


Some scientists believe that, as the comet approaches the sun, the additional energy provided will be enough to charge up the solar cells and may bring the device functional for a little while. So the mission is still not over, as scientists wait anxiously to find out whether the little probe that could will be brought back to life.

1 comment:

  1. Not only that, but there has been speculation that Rosetta itself will be landed (well I say landed, it is not designed as a lander and is therefore more likely to...erm...crash) in order to provide detailed pictures and information about the atmosphere of the comet as it approaches. The ESA appear to be remarkably efficient in terms of using resources!

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