Considering the nature of the Dawn spacecraft’s slow, spiraling entry into orbit around Vesta, it’s a little unclear precisely when orbital insertion was, but NASA is pegging an approximate time of 0447 UTC on July 16. The event is leading to closer and better imagery all the time, the example below being the first full-frame image, taken from the spacecraft’s framing camera on July 24. Here we’re looking at the asteroid from a distance of 5200 kilometers, seeing for the first time the kind of surface detail that has long been hidden from even the most powerful telescopes.
Image: NASA’s Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, 2011. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.
Dawn’s principal investigator Chris Russell (UCLA) likes what he sees:
“We have been calling Vesta the smallest terrestrial planet. The latest imagery provides much justification for our expectations. They show that a variety of processes were once at work on the surface of Vesta and provide extensive evidence for Vesta’s planetary aspirations.”
We’re going to be learning quite a lot about both Vesta and Ceres from coordinated work between the spacecraft’s radio transmitter and Earth-bound antennae, which will be used to monitor signals from Dawn to detect variations in the asteroids’ gravity fields. The intent is to learn more about the interior structure of the two objects. We’ll also use Dawn’s visible and infrared mapping spectrometer to measure the surface mineralogy of both asteroids. Dawn’s first of four intensive science orbits of Vesta will begin on August 11 at an altitude of 2700 kilometers.
A spectacular view of the rotating Vesta is offered in the following video:
Image: In this movie, strung together from a series of images provided by the framing camera on NASA’s Dawn spacecraft, we see a full rotation of Vesta, which occurs over the course of roughly five hours. These images were obtained on July 24, 2011, from a distance of about 3,200 miles (5,200 kilometers).
And let’s close with a closeup of craters in the southern equatorial region:
Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.