<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=windows-1252" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 8.00.6001.19088">
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#dbdbdb>
<DIV>On July 15, NASA's Dawn spacecraft will begin a <BR>prolonged encounter
with the asteroid Vesta, making the mission the <BR>first to enter orbit around
a main-belt asteroid. <BR><BR>The main asteroid belt lies between the orbits of
Mars and Jupiter. <BR>Dawn will study Vesta for one year, and observations will
help <BR>scientists understand the earliest chapter of our solar system's
<BR>history. <BR><BR>As the spacecraft approaches Vesta, surface details are
coming into <BR>focus, as seen in a recent image taken from a distance of about
<BR>41,000 kilometers. The image is at: <BR><BR><A
href="http://www.nasa.gov/mission_pages/dawn/multimedia/dawn-image-070911.html">http://www.nasa.gov/mission_pages/dawn/multimedia/dawn-image-070911.html</A>
<BR><BR>Engineers expect the spacecraft to be captured into orbit at
<BR>approximately 10 p.m. PDT Friday, July 15. They expect to hear from <BR>the
spacecraft and confirm that it performed as planned during a <BR>scheduled
communications pass that starts at approximately 11:30 p.m. <BR>PDT on Saturday,
July 16. When Vesta captures Dawn into its orbit, <BR>engineers estimate there
will be approximately 9,900 miles (16,000 <BR>kilometers) between them. At that
point, the spacecraft and asteroid <BR>will be approximately 117 million miles
(188 million kilometers) from <BR>Earth. <BR><BR>"It has taken nearly four years
to get to this point," said Robert <BR>Mase, Dawn project manager at NASA's Jet
Propulsion Laboratory in <BR>Pasadena, Calif. "Our latest tests and check-outs
show that Dawn is <BR>right on target and performing normally."
<BR><BR>Engineers have been subtly shaping Dawn's trajectory for years to
<BR>match Vesta's orbit around the sun. Unlike other missions, where
<BR>dramatic propulsive burns put spacecraft into orbit around a planet,
<BR>Dawn will ease up next to Vesta. Then the asteroid's gravity will
<BR>capture the spacecraft into orbit. However, until Dawn nears Vesta <BR>and
makes accurate measurements, the asteroid's mass and gravity will <BR>only be
estimates. The Dawn team will refine the exact moment of <BR>orbit capture over
the next few days. <BR><BR>Launched in September 2007, Dawn will depart for its
second <BR>destination, the dwarf planet Ceres, in July 2012. The spacecraft
<BR>will be the first to orbit two bodies in our solar system. </DIV>
<DIV> </DIV>
<DIV>For an image of Vesta and more information about the Dawn mission,
<BR>visit: <A
href="http://www.nasa.gov/dawn">http://www.nasa.gov/dawn</A> and <A
href="http://dawn.jpl.nasa.gov">http://dawn.jpl.nasa.gov</A> <BR>You also can
follow the mission on Twitter at: <A
href="http://www.twitter.com/NASA_Dawn">http://www.twitter.com/NASA_Dawn</A>
</DIV></BODY></HTML>