We’re On The Comet, Baby! Philae Scores A Touchdown

Rosetta team members, including  Flight Director Andrea Accomazzo (left), react to the first signal received from the Philae lander after its successful touchdown on Comet Churyumov-Gerasimenko earlier this morning. Credit: ESA

Around 9:37 a.m. (CST) Philae successfully landed on craggy comet Churyumov-Gerasimenko. The first signal, a voice from another world, arrived at 10:05. While the lander reached the surface in good health and continues to send telemetry, a small problem cropped up. The two harpoons that would anchor the craft to the comet failed to fire.

Check out this James Bond-style Swiss Army knife of a lander. Each instrument includes a short description. To read clearly, click for a large version. Credit: ESA

Right now, mission control is considering whether to re-fire them as well as figure out why they didn’t fire in the first place. In the comet’s low gravity, it’s important that Philae be sitting stably. Just think what would happen if a nearby jet erupted or ice began to vaporize around or under the craft? Weighing only a gram, Philae might easily tip over.

Here we come! The photo was taken by Philae at 8:38 a.m. (CST) when it was just 1.8 miles (3 km) above the comet. Credit: ESA/ESA/Rosetta/Philae/ROLIS/DLR

Hopefully we’ll see that first panoramic landscape photo soon. In the meantime, scientists held a press conference this afternoon to share first results as well as some of the troubles the lander faces.

Although Philae landed right on target and is gathering scientific data at this very moment, there have been problems with the radio link. Communications drop in and out for some as-yet unexplained reason. We know that neither the top rocket thruster (used to push the probe to the surface) nor the harpoons fired to anchor the craft to the comet’s surface. The data even seem to indicate that the lander may have even lifted off the ground and landed again:

Just to give you a flavor for the rugged landscape Philae was headed toward earlier today, this photo was taken by Rosetta at an altitude of 4.8 miles (7.7 km) from the comet’s surface. Credit: ESA

“Maybe today we didn’t just land once. We landed twice!” said Stephan Ulamec, Philae Lander Manager. Much is still preliminary, which is why the agency’s scientists are hard at work on the problem. Another live webcast is scheduled tomorrow at 7 a.m. (CST).

Live updates can be had on Twitter and the Rosetta website.

36 Responses

          1. astrobob

            There were three ways of getting Philae to stick: the top thrusters that pushed the craft downward, the harpoons and ice screws on each of its three legs. The first two failed for sure, and I’ve heard that the screws also didn’t function. Still waiting for a confirmation on that.

          2. Giorgio Rizzarelli

            It seems ESA confirmed that screws appear to have dug into surface. This is probably, partly, what they meant by soft landing. As for the pushing-down thruster they knew already before landing that it was not working. After touchdown it seems the lander lifted and rotated a bit but then stopped. You know, escape velocity is 1m/s (better not skiing there, in afterthought). Finger crossed!

  1. Naming the lander “Ishmael” instead of “Philae” could have done the trick. 😉
    In the same vein, I hope the next euro-russian probe to Mars doesn’t have the word “Phobos” in its name …

    1. Giorgio Rizzarelli

      Sorry second link is identical – In the page scroll up to the latest images, there are two surface closeups.

    2. astrobob

      Hi Giorgio,
      I didn’t see that one with the mountain. Nowhere in it does it say what took the picture. It doesn’t look like the right angle for Philae though. Thanks for the link!

    3. astrobob

      That mountain has to be taken by Rosetta the more I look at it. Still a cool shot! ESA has only released one descent photo of the comet taken by Philae as far as I can find.

      1. Richard Keen

        Thanks for the Daily Mail link, Giorgio. If you go to the link and scroll down to the twitter picture of the screen with the caption “Although no official images from the surface have been released…” you’ll see a pointy rock with a shadow. The same rock appears smaller in the next image captioned “Almost there!” So it looks like the screen image is from very close to the surface, if not on it.
        So… Why hasn’t ESA released any of these images? NASA would have had them out in milliseconds. There seems to have been very little info from ESA since the touchdown, considering that there may be images from the “ground” or just above it. The same caption says “ESA is expected to release the first official shots tomorrow.”
        Frankly, I don’t get it, considering the PR and sheer interest value of this remarkable event.

        1. astrobob

          I don’t see it. I see another closeup of the mountain but nothing that appears shot by Philae. It really surprises me that ESA hasn’t released at least a few more descent images.

          1. Richard Keen

            From Spaceflight Now http://spaceflightnow.com/2014/11/12/european-space-probe-makes-first-landing-on-a-comet/
            It sppears maybe Philae bounced on landing, perhaps rotating and landing again in an unknown orientation. Now it’s out of contact range with the orbiter, and “Officials said the next chance to contact Philae will be around 0600 GMT (1 a.m. EST) when Rosetta again flies in range of the lander.” Hopefully there will updates tonight when it’s midnight in Duluth.
            Perhaps it did not send back any pictures after landing. But it’s strange to get this from Spaceflight Now, the Daily Mail, and the like and not from ESA directly!

          2. astrobob

            I agree. It seems ESA was doing so well up till the landing. I heard that it may have landed twice and rotated, but let’s hope it didn’t land sideways. You’d think there would be a photo but maybe instruments were damaged. Thanks for the link!

        2. Giorgio Rizzarelli

          You’re welcome Richard and thanx for the DailyMail page. Yesterday I also found useful a BBCnews page which posted frequent updates. I too noticed that ESA tended to leave the news aspect, including exclusive pics, more to medias. Possibly a PR strategy, or they simply preferred to focus on work. The live broadcast however was well organized. Now let’s hope the lander is OK and look forward to see the data and images it collected so far.

          1. Giorgio Rizzarelli

            sorry I meant thanx for the SpaceFlight now link. The top 10 images, great. PS I noticed too the rock shadow

          2. Giorgio Rizzarelli

            Bob, if you didn’t notice, the “mountain” shot is simply the neck. It’s described in the caption in the Top10 shared by Richard. “[…] the smaller lobe on the left and the larger lobe on the right. Much of the comet’s activity originates from the neck. The scene also shows the contrast between the rugged material in the cliff walls rising up to the smaller lobe and the soft, more ‘textured’ material that characterises the neck and that is also coating the larger lobe in this region.”

  2. MJ

    Surprised to see such a small Rosetta Team (6?) in Europe…. when landing on the moon NASA had what seemed like hundreds in the control room. Budget cuts, geniues, or did they die off over the last ten years?

  3. MJ

    Yeah..all earthlings are the happy audience. Maybe technological advances. Think of how many folks were needed on an assembly line to build a car…

  4. Troy

    (I was thinking this before it had problems…)I think a better design would have been similar to the Mars Pathfinder without the airbags. Mars Pathfinder used a tetrahedral design and no matter which way it landed it could right itself.
    One thing all space agencies could learn from NASA get those images out, even if they are raw images, as soon as possible. You’re only going to have the limelight so long before it is yesterday’s news.

    1. Richard Keen

      Troy, that airbag design for Mars Pathfinder was superb, and the design fit in with NASA’s Mars policy of “find the water”. So it bounced around to a low point in the crater where it found evidence of water. But ESA did not want Philae to roll into a crater or crevice, and the legged design is much better. It appears it may have succeeded in keeping the lander out of a hole.

      1. Troy

        I’m not advocating the airbags, just the tetrahedral design. They’d still need to aim but orientation wouldn’t matter. Pathfinder actually landed in the correct orientation, but if it didn’t it could just open up and right itself.
        The ESA had a good system, but every system to land and secure failed, after 10 years in the cold of space it isn’t hard to see why but a slightly more innovative design might have made a difference.

  5. Giorgio Rizzarelli

    News of 1 hour ago with a pic from landed Philae (it’s sending more).
    It landed not two, but three times. It’s now clear that yesterday it bounced for two hours, hundreds of meters, maybe 1Km high while the comet was rotating below. There was a second smaller bounce.
    It is now stable, although no harpoons and no screws.
    No harpoons refire planned, and no drilling, for now, too risky.
    One leg is off. Sitting at an angle, possible on a slope, but getting data.
    One issue is that it’s in a shadowed position receiving few hours of sunlight on the panels (why didn’t they make it nuclear powered like Curiosity?).
    They’re trying to get a photo from the mothership to understand where it is.
    My personal guess would be in the neck, which would be interesting to monitor activity, but it can be everywhere.

        1. Giorgio Rizzarelli

          New Live BBC press conference now going visible also in play at the link I sent above (the one with the image)

          In the conference Ulamec revealed the data about the landing(s):
          – 1st jump 2hour rebound 38cm/s probably up1Km high, probably 1Km distance
          – 2nd jump 3cm/s for 7min

          Using the radar and the comet dielectric properties it’s estimated that the lander is the famous big crater/depression on the front of the small lobe, sitting on the rim, so not distant from the original planned site.

          It seems all the instruments are working, except that of course they don’t activate those with mechanical properties for it’s too risky with the non anchored lander.

          Various images were taken on the surface, I took some screenshots from the press conference, I’m sending them you by email

          1. Giorgio Rizzarelli

            Other info from the conference:

            – the surface image (the one with the leg shadow in corner we were talking about yesterday) was taken lenn than one minute before touchdown. It has resolution 4cm/pixel.

            – A journalist asked about when they will try drilling, if they do. That depends on battery. Due to the shadow position, the battery will probably last one day, critical the day after (I don’t know if comet day meant), so if drilling is done it will be in a couple of days. When the battery is low Philae is programmed to enter hybernation and to possibly wake up months after when getting more Sun

          2. astrobob

            Thank you Georgio. I went back and listened to most of the press conference and shot many a screen grab. Busy this morning with both Universe Today and my own blog. Still have details to add. I appreciate the information you shared. Thanks again!

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