Mankind's next small step (or giant leap) spaceward is NASA's Dawn Mission to the Asteroid Belt, planned for launch in late June or July.  On Sunday, April 22, 2:30 p.m. at the Altadena Public Library, Dr. Marc Rayman of JPL will describe the Dawn mission, including its use of ion propulsion and its two exotic destinations.
 
The Dawn spacecraft will orbit asteroids Ceres and Vesta, which are among the last unexplored worlds in the inner solar system.  They are the two most massive residents of the asteroid belt, a vast collection of bodies between Mars and Jupiter.  Ceres is so large that it is included in the new category of dwarf planets (along with Pluto). 
 
The alien landscapes the Dawn orbiter will reveal are expected to provide humankind with a new perspective on the solar system.  Remnants from the time when planets were formed, Ceres and Vesta may hold clues to help scientists understand the dawn of the solar system.  This will be the first spacecraft ever to orbit an object in the asteroid belt and the first ever to orbit two targets.  Such a mission would be impossible without the use of ion propulsion, a technology that has, until now, been mainly in the domain of science fiction.
 
The Altadena Public Library is located at 600 E. Mariposa Street in Altadena, two stop signs west of Lake Avenue at the corner of Mariposa and Santa Rosa Avenue ("Christmas Tree Lane").  Exit the 210 freeway at Lake Avenue in Pasadena and go approximately 2.5 miles north to Mariposa Street in Altadena.  Turn left on Mariposa, go to the second stop sign, turn left on Santa Rosa, and turn into the parking lot at the first driveway on your right.  The lecture is in the library's Community Room.
 
MWOA is a public-membership support group for the Mount Wilson Observatory, a major astronomical research facility located in the San Gabriel Mountains.  MWOA's goals include improving the public's awareness of this observatory's rich history and ongoing scientific and educational programs.  For information about MWOA membership, call Don Nicholson at (310) 476-4413, or see the MWOA web site, www.mwoa.org.