Video update from Lander Control Centre

As tweeted by the German Aerospace Center (DLR) yesterday, a mini status update direct from the Lander Control Center in Cologne. In short, the teams are still working hard on trying to re-establish contact with the lander.

Comments

12 Comments

  • Gerald says:

    People likely think, Rosetta would orbit the comet.
    To tell it more explicitely: This isn’t the case. Rosetta stays in a zone “above” the the comet, where establishing contact to Philae appears most likely.

    • Peter says:

      ESA itself usually writes that Rosetta “orbits”. From a nominal calculation at http://blogs.esa.int/rosetta/2015/06/26/rosetta-and-philae-searching-for-a-good-signal/#comment-478312, its rotation period around the comet would be 246 earth days, which is practically stationary, It seems Rosettas position is at “sunset” above the comet. Also Rosetta orbits now around the sun at 6.4 years, together with the comet.

      • Gerald says:

        Around the sun, yes.
        Around the comet, no, not at the moment. That’s why I’ve written the post.
        The comet is rotating. So Rosetta’s view to the comet changes. But relative to a non-rotating reference frame Rosetta isn’t orbiting in the intuitive way.
        That’s achieved by a series of small trajectory corrections, zigzagging within a cone with anticipated best opportunities to contact Philae.

  • Jef says:

    Obviously you have a very nice model of the comet there. I think it would be a good idea to indicate the rotation axis on this model, and also the position of the sun. Then everybody could understand better the variation of “day” and “night” on the comet, and also the variation of “summer” and “winter”, to illustrate the change in illumination time for Philae when the comet comes closer to the sun.

  • JvZ says:

    Transmitter range of Philae is a few hundred meters up to 150 Km.See page communications
    http://www.rmki.kfki.hu/~szalai/Publications/Bibring-Philae-2006-fulltext.pdf

  • Harvey says:

    It is ‘up to 150km’ at 16kbit/second.
    It is possible Philae (and the Rosetta receiver) has the ability to use slower data rates, in which case the range increases roughly as the square root of the decrease. So say at 4kbit/sec you expect 300km range.
    The article does mention other modes, so it may have this capability.
    If anyone in the team has a moment to comment that would be very welcome, but I’m sure you are busy. Good luck…….

    Another possibility might be that Philae has shifted, even in the very low G environment, as it looked fairly precarious and the comet is more active now. This could change the antenna pointing; I’m sure the team will have considered that possibility.

    • Harvey says:

      Oops; slipped up. If you reduce the rate by a factor four, you halve the noise power.
      But signal power goes as the reciprocal square of the range.
      So reducing the data rate by a factor four doesn’t double the range, it increases it by root two to maintain the same signal to noise ratio, so from 150km to 212km, not 300km.

  • Peter says:

    I found this mini status update (Video 30 seconds)
    https://twitter.com/DLR_en/status/616963983002730496
    Date 03 jul 2015 06:37h
    It is tried to activate CONCERT with unidirectional command to Philae

  • Booth says:

    Emily

    This seems like an appropriate thread to post this query, as it has to do with communications …

    I would sincerely like to re-establish communications with ESA’s Rosetta blog. Tabulated is a list of various threads with the number of comments I can see using FireFox (V39) and my ancient Android OS smartphone, respectively. Furthermore, I reside in North America, and expect I am being served by a local satellite, separate from ESA’s main system.
    30/32 – Mission Extended
    00/00 – CW 23 June
    04/09 – Sinkhole Jets
    03/08 – Lander Control Centre
    06/09 – CW 21 June
    41/41 – Searching For Signal
    67/74 – Exposed H2O Ice
    23/23 – Tracking Debris
    30/30 – MIRO Maps Water
    18/19 – Listening for Lander

    Discrepancies between these numbers have been much more significant at various points in the past. For example, on the Exposed H2O Ice thread, there was a jump from one comment to 45 comments on the 29th of June. As an aside, there is no “Reply” hyperlink on my Android device, so all I can do is read what people are saying.

    I hope there is a simple solution to this problem. A very time consuming work term is about to conclude for me, and I hope to rejoin the conversation. Especially as we approach perihelion!

    Thanks for your attention in this matter! And an additional thank you to both you and Claudia for your excellent updates!

    • emily says:

      Hi Booth, Thanks for the follow-up messages to this, good that it was just a browser issue on your side. Best wishes,
      Emily

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