Dawn: Up close and personal with Vesta

As I may have mentioned, early tomorrow morning, 9am [BST] 16 July, Nasa’s Dawn spacecraft is expected to be captured into orbit by the 530km-wide giant asteroid Vesta.  They won’t know for sure until a scheduled communications pass at 8.30am [BST] on Sunday 17 July.  Here’s the latest image of Vesta taken by Dawn on 9 July at a distance of about 26,000 miles (41,000 km). 


NASA’s Dawn spacecraft obtained this image with its framing camera on July 9, 2011. It was taken from a distance of about 26,000 miles (41,000 kilometers) away from the protoplanet Vesta. Each pixel in the image corresponds to roughly 2.4 miles (3.8 kilometers) Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

And from the JPL press release

When Vesta captures Dawn into its orbit, engineers estimate there will be approximately 9,900 miles (16,000 kilometers) between them. At that point, the spacecraft and asteroid will be approximately 117 million miles (188 million kilometers) from Earth.

“It has taken nearly four years to get to this point,” said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Our latest tests and check-outs show that Dawn is right on target and performing normally.”

Engineers have been subtly shaping Dawn’s trajectory for years to match Vesta’s orbit around the sun. Unlike other missions, where dramatic propulsive burns put spacecraft into orbit around a planet, Dawn will ease up next to Vesta. Then the asteroid’s gravity will capture the spacecraft into orbit. However, until Dawn nears Vesta and makes accurate measurements, the asteroid’s mass and gravity will only be estimates. So the Dawn team will need a few days to refine the exact moment of orbit capture.

The BBC report has a great quote

Initially, Dawn will be about 16,000km (9,900 miles) from the asteroid, but this distance will be reduced over time.

Mission scientists hope to get within 200km of the surface but the team do not intend to take any unnecessary risks.

“We would like to get as low as possible but if we crash Dawn, Nasa would understandably be very angry at us,” Principal Investigator Chris Russell told BBC News.

Indeed.  Dawn has a date with the dwarf planet Ceres, after all.  [That’s a dwarf planet like Pluto, right? – Ed]  Sort of…   Here’s an animated overview of the mission. [Video Credit: NASA/JPL-Caltech]

There’s an August 2010 Nasa preview of the Dawn Mission here – with a video presentation narrated by Leonard Nimoy – as opposed to the previously noted video narrated by William Shatner. 

More Dawn related  videos and interviews here.

Update  Dawn has confirmed that it has entered orbit around Vesta, the first probe ever to enter orbit around an object in the main asteroid belt between Mars and Jupiter.

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  • earther

    As I understand it, there’s no special manoeuver to enter orbit this time because the robot is using purely ion propulsion and it’s won’t be in a stable orbit for weeks. Apparently it’s been manoeuvering for a long time to get on the right trajectory and it’s already in a position to enter orbit with no more push than it’s been pushing for years.

    For people in the US and who know people in the US: it’s time to flex your political muscles because an insane cut on the exploration budget (and on another more politically charged but even more important budget) has been voted in a Parliamentary committee in favor of a new launch system. If this goes through, what was left of humanity’s main space exploration program (NASA’s) will be left in shambles and no one’s ready to pick up the ball yet as far as the outer Solar system is concerned.
    My guess is that means no Europa or Uranus mission for decades and probably no Neptune/Triton in our lifetimes. I hope I’m not being overly dramatic here but NASA’s already was already concentrating its exploration budget on Mars before the cut…

  • Unfortunately, earther, the band of once intrepid daredevil explorers have, as is usually the case, been taken over by the beancounting bureaucrats. We will have to constrain our excitement for projects such as Dawn.

  • earther

    Well, they are planning to spend a lot of money on that launch system…

    There are more ambitious projects than Dawn already under way. They won’t be cancelled, except for the new space telescope (which is not really exploration). So excitement in the next few years is guaranteed.
    My concern is mainly for the future. I count only three robots in or bound for the outer system (Cassini, New Horizons and one due for launch next month). So far as I know, there’s nothing in the pipeline and with that cut, I’m afraid we aren’t going to see anything there for a long, long time after about 2018.

  • Not quite relevant, but adjacent …

    Full page review (by Arthur H.Knoll of Harvard — cf: Life on a Small Planet, 2003) of Ted Nield’s Incoming! in the current issue of The Times Literary Supplement.

    Mainly concerned with the Yucatán meteorite strike of the Cretaceous period, which may, or may not the cause of the dinosaur extinction. Either way, it certainly screwed up the belief-system of the likes of Alderman Edwin Poots, MLA.

  • Pete Baker

    Update Dawn has confirmed that it has entered orbit around Vesta, the first probe ever to enter orbit around an object in the main asteroid belt between Mars and Jupiter.