7 comments on “Philae Lander Has Landed – On a Comet!

    • Thanks for stopping by Jeremy!

      There was some American-made stuff on Rosetta, but not the lander:

      The lander is provided by a European consortium under the leadership of the German Aerospace Research Institute (DLR). Other members of the consortium are ESA and institutes from Austria, Finland, France, Germany, Hungary, Ireland, Italy, and the United Kingdom.

      Rosetta’s total launch mass is 3,000 kilograms. The spacecraft carries 1,670 kilograms of propellant and the lander weighs 100 kilograms.


      So Philae, the lander, weighs 200 kilograms = 440 lbs but gravity is 1/10000 of earth gravity so that equals 0.044 lbs = .704 oz!

      No spacecraft has ever soft-landed on a comet. What are the risks during such a landing and how are they being minimized?

      We have some idea of the risks, but no one knows for sure. This is one of the fascinating aspects of the mission. The density and surface roughness of the nucleus are not really known and its gravity is extremely low. We have tried to compensate for these factors in the design of the lander. There will be two harpoons to anchor it to the surface so that it can be reeled in like a fish on a line. There are also ice screws in each foot, which can be rotated to help to secure the spacecraft on the surface. The lander is also designed to stay upright on a slope of up to 30 degrees.

      We will try to ensure an adequate margin of safety by mapping the surface of the nucleus at high resolution (a few cm) during the long orbital observation phase so that we know the size, density, surface roughness and other properties of the nucleus. This will enable us to select a suitable landing site.


      Can you provide a link to the problems they are having with the drill anchors?


  1. I guess now that there’s bad news, it’s all over the ‘net! My apologies to all for not being more on top of it and Hat Tip to Jeremy! I, I, I get….busy.

    From: ESA FAQ site quoted above:

    Under which circumstances would the mission be considered a failure?

    “Obviously we are hoping and expecting that the lander will succeed in sending back the first images and in-situ measurements ever obtained from a comet nucleus. However, if it fails, the primary science mission can still continue – the most important, long-term scientific investigations will be done by the eleven experiments on the orbiter. These will enable us to map and characterise the nucleus in unprecedented detail, as well as enable us to gain remarkable new insights into the processes taking place, as the nucleus is warmed by the Sun and becomes increasingly active. “


  2. Looks like for whatever reason, the anchoring harpoons didn’t even fire!

    Philae, (the lander) which was simply dropped unceremoniously from the mother-ship onto the comet, hit the surface going about a meter a second, harpoon anchor thingys didn’t fire so it bounced up a bit over a kilometer, fell back to the deck bounced again, but this time not that high, then settled in on its side partially shadowed by an overhanging cometic cliff-like feature; thus shading the super-sophisticated; never tried before; really fashionable – you know – sustainable, solar panels thus rendering them superfluous.

    Oh for a simple 1 kg nuclear battery!


  3. Pingback: Comets – Wet Ones Too! | Alan Olee Book Report

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