Dawn dips down to Vesta

By Phil Plait | December 21, 2011 10:43 am

Last July, the spacecraft Dawn slipped into orbit around Vesta, one of the largest asteroids in the solar system — the first time a probe had ever orbited a main-belt asteroid. From its height of 16,000 km (almost 10,000 miles), it started mapping the 500 km (300 mile) wide rock, returning the first close-up pictures in amazing detail.

Over time, the height of the spacecraft over the surface was lowered, and it has now attained its lowest altitude orbit: a mere 200 km (120 miles) over the asteroid’s cratered, battered terrain. I mean asteroidain. Whatever. Anyway, it’s now sending back higher-resolution images than ever before, including this very cool one:

[Click to asteroidenate.]

This shows a region of Vesta about 18 km (11 miles) on a side, dominated by a ginormous impact crater. You can see how the crater’s central floor is flat, and you get just a hint of a slightly raised rim around the edge of the crater. The shadow of the rim falling into the crater also suggests variations in the elevation of the rim top (though craters in the floor of the big crater distort the shadow’s edge a little too). I like all the small craters inside the big one; they come in a variety of shapes, some deep, some shallow, and one (near the rim at the bottom of the picture) appears to be sliced in half; I suspect material flowing down the crater wall in a landslide half buried it. Light colored streaks pointing down the crater wall indicate slides do occur. Triggered by other impacts, maybe?

We’ll be seeing lots of amazing images and science coming from this spacecraft over the next few months. Be sure to check the mission’s Image of the Day pages to stay on top of what we’re seeing on Vesta… but be quick, because time’s running out. In May, Dawn will leave Vesta and start a new journey for a new target: the largest asteroid in the solar system, Ceres. It arrives there in 2015.

Image credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA

Related posts:

Like asteroid, like moon
Dawn of a new Vesta
Vesta’s odd bottom
Vesta in breathtaking detail

CATEGORIZED UNDER: Astronomy, Pretty pictures
MORE ABOUT: Ceres, crater, Dawn, Vesta

Comments (15)

Links to this Post

  1. Dawn at Vesta | ***Dave Does the Blog | December 21, 2011
  1. amstrad

    How does one maintain a reasonably predicatable orbit around such a low mass and lumpy object?

  2. CR

    “Whatever,” indeed… can we just say “terrain” ragardless of which object we’re observing, and know we’re referring to the ‘ground’ of said object? That’s one thing I’ve always detested about astronomy pedantry… “gee” and “terr” refer to Earth, so you can’t use “apogee” or “terrain” for any other object except Earth. Worse, you have to come up with similarly started words suffixed with the name of the particular object being discussed. SHEESH, that’s dumb! It’s more dumb than the ‘what’s the definition of a planet?’ debate, and a lot more pointless, and I’m usually a stickler for grammatical correctness.
    Anyway, moving on…

    WOW! What a cool photo! Every asteroid mission has brought us new images of asteroids that I scarcely imagined as young child. As others have said in earlier posts, asteroids were (at best) points of light in a telescope, most of which were imagined to probably looked like Phobos & Deimos. Now that we’ve been to more than a few, we can see that there’s a lot more inviduality to the things. I know they’re still just chunks of rock–leftovers, if you will–but they are so interesting.
    I eagerly await the next stunning vistas of Vesta, but I feel 2015 can’t come soon enough… onward to Ceres!

  3. jason

    I keep getting turned around by the illusion that they are hills, not craters. I know our natural inclination it to assume light comes from above, and for me at least, to the left. Is there a particular reason that images I have seen of the moon and other non-terrestrial features seem to put the light source coming from the bottom or right? That seems to enhance the illusion andI would think make it harder to properly analyze the images. Is there a particular reason for this or is it just observation bias since those are the ones that stick in my mind?

  4. CR

    Meanwhile, going through the Dawn image gallery, check out this one… http://dawn.jpl.nasa.gov/multimedia/images/FC21A0014298_page.jpg The relatively fresh craters at upper right are partially filled in with slide material, and what looks like rilles are near them (and seem to actually cut across them). Very interesting topography there! (Cue the ‘it’s an alien mining operation’ crowd in three, two, one…)

  5. Chief

    Cool. Makes me look forward to 2015 much more.

    Do these robotic visits mean that we may have a mission objective for NASA with the new deep space manned rated rockets.

  6. QuietDesperation

    can we just say “terrain” ragardless of which object we’re observing, and know we’re referring to the ‘ground’ of said object?

    Yes. It’s generic. It’s really not something to OCD about.

  7. ceramicfundamentalist

    cool pic, almost fractal. craters in craters in craters…

  8. Like Jason says (above) and regardless of which direction the shadow comes from I always see craters as sticking out rather than in, like they should be. It wouldn’t surprise me if that was called something, just knowing would help. But the real issue is even if I download the pic and rotate it, it STILL looks wrong. Annoying, yes, and not your fault but was wondering if anyone knew what was going on with that?

  9. Bobby LaVesh

    What’s the black shape in the bottom right- looks bell-like (on its side) seems a rather unnatural looking shadow for the peak. Is that just how the image is rendered.

  10. Douglas Troy

    Phil, every time I read one of your write-ups on something like this, I feel like I’m reading the script for a TV show called CSI Astronomy.

    “Next Week, Phil tries to determine if the smallish craters on the outer rim of the larger crater were caused by the suspect T11192-A from the Kuiper belt … or if it was just Col Mustard with the candle stick in the library, as usual”.

  11. Tony Mach

    For me, how I think the form of this crater should be and how the shadow therefore should look like doesn’t add up to how it actually looks like. I wonder what I am missing.

  12. @1. amstrad asked : “How does one maintain a reasonably predicatable orbit around such a low mass and lumpy object?”

    By using good science and good rocketry that’s how! 😉

    Also getting in pretty very close and using the thrusters to adjust the orbit and match velocities effectively. It is pretty neat that they can do this – and remember that we’ve orbited much smaller asteroids than Vesta before already eg. asteroid Eros with the NEAR-Shoemaker spaceprobe and Japan’s Hayabusa around asteroid Itokawa which I think holds the record for smallest rock yet orbited. I think Hayabusa actually orbited it for a time anyhow.

    BTW. Click on my name for youtube clip on one instrument that may have helped at least with asteroid Eros. :-)

    Awesome image here – well done Dawn can’t wait to see Ceres in such detail too. :-)

  13. @ ^ ” I think Hayabusa actually orbited it for a time anyhow.”

    See :


    which suggests maybe not quite.

    Click on my name this comment for a great if silent Youtube clip showing an animation of what the Hayabusa mission did as well. Or cut’n’paste :

    HAYABUSA Probe Mission overview CG/ JAXA

    into the Youtube search box.

    See :


    For more NEAR Shoemaker~wise & note also the Rosetta mission :


    which will “accompany” (& land on) comet Churyumov-Gerasimenko around our Sun if all goes to plan as well.

    Hope this is useful / enjoyable for y’all. :-)

  14. Marc JX8P

    Absolutely amazing picture, really makes you feel like you’re there…


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