• Question: What happened to the comet and how from 10 years ago they have been waiting for this moment till now?

    Asked by Erbz to David, Arthur, Clare, Daniel, Tora on 13 Nov 2014. This question was also asked by 284gdna42.
    • Photo: David Wilson

      David Wilson answered on 13 Nov 2014:

      It took 10 years for Rosetta to get to Comet 67P because it is on a very different orbit to the Earth. Rosetta had to change how fast it was going and what shape orbit it had around the sun, and do it precisely enough to catch up with the comet- and then be in exactly the same obit as the comet when it got there.
      The rocket it launched on wasn’t powerful enough to do this, so Rosetta had to use the gravity of planets. It flew past Mars once and Earth three time, getting tugs and pushes form their gravity to get it into the right orbit. Flying in between the planets takes a long time, so that’s where the 10 year journey came from. I’m still amazed that after all that time, it seems to have worked so well!

    • Photo: Daniel Parsons

      Daniel Parsons answered on 14 Nov 2014:

      Hi there Erbz,

      The comet loops around the Sun in-between the orbits of Jupiter and Earth, that is, between about 800 million and 186 million kilometres from the Sun. As David explains the probe was spun up using a set of sling shots around mars and earth a few times to get up some speed and also get onto the right path to catch the comet. In total these loops around Earth in 2005, both Earth and Mars in 2007, and Earth again in 2009 meant that by the time the Rosetta probe reached the comet it had travelled of over 6.4 billion kilometres – this is why it took 10 years! It also took a lot of maths to work out how to do it!

      It is pretty incredible when you think that it has travelled that far and fast (at about 34,000 miles per hour) that it is now travelling at just 2 miles per hour different to the comet and is looping around it having dropped a probe to the surface!

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