NASA’s Dawn spacecraft obtained this image with its framing camera on July 17, 2011. It was taken from a distance of about 9,500 miles (15,000 kilometers) away from the protoplanet (aka asteroid) Vesta. Each pixel in the image corresponds to roughly 0.88 miles (1.4 kilometers).
When Vesta captured Dawn into its orbit, there were approximately 9,900 miles (16,000 kilometers) between the spacecraft and asteroid. Engineers estimate the orbit capture took place at 10 p.m. PDT Friday, July 15 (1 a.m. EDT Saturday, July 16).
Vesta is 330 miles (530 kilometers) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes have obtained images of Vesta for about two centuries, but they have not been able to see much detail on its surface.
Proximity does make a difference. For example, here’s an earlier image from the Dawn spacecraft of asteroid Vesta.
This image was taken from a distance of about 26,000 miles (41,000 kilometers), as Dawn approached Vesta last week.
Dawn principal investigator Christopher Russell from the University of California, Los Angeles said:
We are beginning the study of arguably the oldest extant primordial surface in the solar system. This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta’s history, as well as logging the onslaught that Vesta has suffered in the intervening eons.
Bottom line: NASA’s Dawn spacecraft is now safely in orbit around a main-belt asteroid Vesta, and it is returning images.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.