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Home Forums General Discussion Rosetta Target Double Comet

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This topic contains 83 replies, has 4 voices, and was last updated by  Tej 8 months, 1 week ago.

Viewing 15 posts - 61 through 75 (of 84 total)
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  • #9240

    Tej
    Participant
    Topics: 36
    Replies: 582

    Which reminds me: my “Can-o-Worms” can-opener has just been sharpened, so…

    Is it me or does Brian Cox take an awful long time to say not very much in his current series?

    [Pulls pin, throws hand grenade, quickly dons tin hat…]

    You might be right but its all so “profound”! 🙂

    Hey what’s with all this smoke….

    #9253

    Mike Meynell
    Moderator
    Topics: 119
    Replies: 745

    Very interesting meeting at the BAA last night. As the main programme finished earlier than expected, Nick James (who, by the way, was a very deserving recipient of the 2014 Merlin Medal last night… that’s me and Martin “photobombing” the shot in the bottom right!) gave a impromptu talk about Rosetta… in particular, the problems of landing the Philae Lander on Comet 67P.

    A really fascinating 20 minutes, which served to highlight the immense problems that Philae will face. ESA put the chance of success at no better than 50/50, and I can see why after seeing this presentation. On this occasion, I don’t think ESA are deliberately playing down the chances of success… the issues are real.

    First of all, ESA had been searching for an area of the comet where there was no incline greater than 30 degrees. No such area exists… they’ve chosen an area with the least number of inclines, but there are still some very nasty slopes. They can only be accurate within a 1 square kilometre area… so there are lots of areas where, if Philae were to land there, it would most likely roll over and that would be the end of the lander.

    In order for Rosetta to deliver Philae to the comet, it ejects the lander 7 hours prior to landing. Philae has no lateral thrusters. Once it’s ejected, that’s it… the small gravitational pull of the comet will do the rest. There is no way of changing course if it looks like it’s heading towards disaster. Note that the comet is rotating all of the time whilst Philae is on its way – a whole 7 hours. Philae only has a small rocket motor on the top to aid in landing… in fact they are not even going to use this rocket. Philae was originally designed to land on a much smaller comet (47P), but the Ariane rocket explosion delayed the mission, so they targeted 67P instead. As 67P has a larger gravitational pull, the rocket motor won’t be used.

    So, in summary… on the morning of 12 November, Philae will detach from Rosetta. We have a good knowledge of the trajectory of the spacecraft. The comet has a rotating nucleus… and we have a reasonably good idea of the gravitational field. Philae has no control over it’s trajectory after release and it can only target a square kilometre where probably 30% of the area is unsuitable for landing. Everything is automated as the distances are too large. As Nick said, if this works, it will be one of the most extraordinary things that we’ve ever done.

    If Philae lands, its batteries will last about 50-60 hours. However, they hope that it will land in such a way that it can recharge the batteries using solar panels, meaning that it could operate all the way to the Sun.

    I’ll certainly be glued to the internet on 12 November, but I’m much less positive about success now.

    Still, at least the Rosetta spacecraft will continue to operate as 67P comes closer to the Sun. Regardless of the success of Philae, this has still been an extraordinary mission.

    #9257

    Brian Blake
    Participant
    Topics: 187
    Replies: 409

    I shall also be glued to internet, let us hope it is successful.

    #9298

    Brian Blake
    Participant
    Topics: 187
    Replies: 409
    #9327

    Brian Blake
    Participant
    Topics: 187
    Replies: 409
    #9404

    Brian Blake
    Participant
    Topics: 187
    Replies: 409
    #9420

    Brian Blake
    Participant
    Topics: 187
    Replies: 409
    #9454

    Brian Blake
    Participant
    Topics: 187
    Replies: 409
    #11200

    Brian Blake
    Participant
    Topics: 187
    Replies: 409
    #11272

    Mike Meynell
    Moderator
    Topics: 119
    Replies: 745
    #11273

    Brian Blake
    Participant
    Topics: 187
    Replies: 409
    #11275

    Tej
    Participant
    Topics: 36
    Replies: 582

    Oh wow! I’m sure there some tears of joy from the Philae team…i am feeling emotional too…

    rise and shine little Philae, long day ahead, theres work to be done!

     

    Such joyful news.

    #11278

    Andy Sawers
    Moderator
    Topics: 112
    Replies: 587

    It’s frankly astonishing. It’s operating with 24 watts – about the strength of a dull lightbulb – in -35C and it’s around 300 million km away. http://sci.esa.int/where_is_rosetta/ Yes, I realise it’s up-linking to Rosetta which then retransmits to Earth. But crikey, it’s still blooming amazing!

    #11279

    Andy Sawers
    Moderator
    Topics: 112
    Replies: 587

    Of course, the reason Philae woke up is it’s so keen to find out who’s going to win the IAU ‘Name an exosystem’ competition that Christina’s been organising 😉

    #11353

    Mike Meynell
    Moderator
    Topics: 119
    Replies: 745

    Good news… mission extended by 9 months to September 2016…

    http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_mission_extended

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