NASA News: NASA's Dawn Spacecraft Enters Orbit Around Asteroid Vesta

PASADENA, Calif. -- NASA's Dawn spacecraft on Saturday became the
first probe ever to enter orbit around an object in the main asteroid
belt between Mars and Jupiter.

Dawn will study the asteroid, named Vesta, for a year before departing
for a second destination, a dwarf planet named Ceres, in July 2012.
Observations will provide unprecedented data to help scientists
understand the earliest chapter of our solar system. The data also
will help pave the way for future human space missions.

"Today, we celebrate an incredible exploration milestone as a
spacecraft enters orbit around an object in the main asteroid belt
for the first time," NASA Administrator Charles Bolden said. "Dawn's
study of the asteroid Vesta marks a major scientific accomplishment
and also points the way to the future destinations where people will
travel in the coming years. President Obama has directed NASA to send
astronauts to an asteroid by 2025, and Dawn is gathering crucial data
that will inform that mission."

The spacecraft relayed information to confirm it entered Vesta's
orbit, but the precise time this milestone occurred is unknown at
this time. The time of Dawn's capture depended on Vesta's mass and
gravity, which only has been estimated until now. The asteroid's mass
determines the strength of its gravitational pull. If Vesta is more
massive, its gravity is stronger, meaning it pulled Dawn into orbit
sooner. If the asteroid is less massive, its gravity is weaker and it
would have taken the spacecraft longer to achieve orbit. With Dawn
now in orbit, the science team can take more accurate measurements of
Vesta's gravity and gather more accurate timeline information.

Dawn, which launched in September 2007, is on track to become the
first spacecraft to orbit two solar system destinations beyond Earth.
The mission to Vesta and Ceres is managed by NASA's Jet Propulsion
Laboratory in Pasadena, Calif., for the agency's Science Mission
Directorate in Washington. Dawn is a project of the directorate's
Discovery Program, which is managed by NASA's Marshall Space Flight
Center in Huntsville, Ala.

The University of California, Los Angeles, is responsible for the
overall Dawn mission science. Orbital Sciences Corp. of Dulles, Va.,
designed and built the spacecraft. The German Aerospace Center, the
Max Planck Institute for Solar System Research, the Italian Space
Agency and the Italian National Astrophysical Institute are part of
the mission's team.

For information about the Dawn mission, visit:

http://www.nasa.gov/dawn

To follow the mission on Twitter, visit:

http://www.twitter.com/NASA_Dawn

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NASA, United Launch Alliance Announce New Commercial Crew Agreement

DENVER -- NASA and United Launch Alliance (ULA) managers will hold a
news conference on Monday, July 18, at ULA headquarters in
Centennial, Colo., to announce a new Commercial Crew Development agreement.

The news conference will begin at 11 a.m. MDT in the first floor
conference center.

To participate, journalists must RSVP to ULA's Chris Chavez at
chris.s.chavez@ulalaunch.com by 9 a.m. MDT on Monday. Reporters also
may participate by calling 800-951-1214. Media representatives must
call by 11:15 a.m. to join the news conference.

The briefing participants are:

-- Ed Mango, NASA Commercial Crew Development program manager
-- Dan Collins, chief operating officer, ULA
-- Dr. George Sowers, vice president, ULA business development

For information about United Launch Alliance, visit:

http://www.ulalaunch.com

For information on NASA's Commercial Crew Development Program, visit:

http://www.nasa.gov/exploration/commercial/

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