Last swing for Rosetta

As the Rosetta comet-chaser swung by Earth one last time yesterday morning before heading out for its date with the comet, scientists are hoping the mission will help unravel the mysteries of how the solar system evolved.

The European Space Agency’s (ESA) mission controllers confirmed yesterday that its spacecraft Rosetta had skimmed past our planet as planned to pick up another gravity boost before heading out for its rendezvous with comet 67P/Churyumov-Gerasimenko in 2014.

Rosetta depends on these gravity boosts in order to reach speeds it would not be able to achieve otherwise, and has previously done two swing-bys of Earth and one of Mars in order to reach its speed at the time of its swing-by yesterday of 13.34 km/s.

By 2014, at a distance of almost 700 million kms from the sun, Rosetta will then release its Philae lander onto the icy nucleus of the comet by using a harpoon to prevent it bouncing off, and which will then begin a series of experiments on its surface.

The Rosetta spacecraft, meanwhile, will orbit the comet for about a year as they both head towards the sun.

Analysing the comet is hoped to unlock secrets about the beginnings of life in the universe. As ESA said, “As the most primitive objects in the solar system, comets carry essential information about our origins. Their chemical compositions have not changed much since their formation, therefore reflecting that of the solar system when it was very young and still ‘unfinished’, more than 4600 million years ago.

“By orbiting Comet 67P/Churyumov-Gerasimenko and landing on it, Rosetta will allow us to reconstruct the history of our own neighbourhood in space. Rosetta will also help to discover whether comets contributed to the beginnings of life on Earth. Comets are carriers of complex organic molecules, delivered to Earth through impacts, and perhaps played a role in the origin of life.”

It is also hoped Rosetta will shed some light on what is causing spacecraft to mysteriously accelerate when they perform these swing-bys, which gain more speed than expected. These accelerations have led some scientists to propose that an “exotic new physics” is the cause, involving modifications of Einsteins’s general relativity.

The video below, courtesy of ESA, helps visualise these swing-bys (although apologies for it being so small).

I think a comment piece on the Guardian today makes a good point of applauding those who got the Rosetta project going for their ability to play the long game:

“Rosetta is a wonderful example of the long view.

“The scientific pay-off from Rosetta could be huge. But contemplate the generosity of vision that made the mission possible. Some of those who lobbied for Rosetta will have died by the time the first results are delivered. Some young scientists who will build their careers on the data from Rosetta were not born when the mission was conceived. If, as Harold Wilson famously observed, a week is a long time in politics, Rosetta is a reminder that we can also think on a celestial timescale.”

Top image of Rosetta’s second Earth swing-by, by C. Carreau, courtesy of ESA.

© Melanie Hall 2017