Shortly after sunrise [
http://www.nasa.gov…dawn-20070927a.html ] on Thursday at Cape Canaveral [
http://www.nps.gov/…] Air Force Station, the Dawn spacecraft [
http://www.nasa.gov…] began its journey to the asteroid belt, arcing eastward into a blue and cloudy sky. Dawn's voyage began on a conventional, chemically fueled [
http://exploration.…combst1.html ] Delta II rocket [
http://exploration.…bgmr.html ], but will continue with an innovative ion propulsion system [
http://dawn.jpl.nas…index.html ]. The spacecraft's extremely efficient ion engines [
http://science.nasa…] will use electricity derived from solar power to ionize xenon atoms and generate a gentle but continuous thrust. After a four year interplanetary cruise, Dawn will orbit two small worlds [
http://antwrp.gsfc.…], first Vesta and then Ceres. Vesta is one of the largest main belt asteroids, while nomenclature introduced by the International Astronomical Union in 2006 classifies nearly spherical Ceres as a dwarf planet [
http://solarsystem.…profile.cfm?Object=D warf&Display=Overvie wLong ].
Explanation
Shortly after sunrise [
http://www.nasa.gov…dawn-20070927a.html ] on Thursday at Cape Canaveral [
http://www.nps.gov/…] Air Force Station, the Dawn spacecraft [
http://www.nasa.gov…] began its journey to the asteroid belt, arcing eastward into a blue and cloudy sky. Dawn's voyage began on a conventional, chemically fueled [
http://exploration.…combst1.html ] Delta II rocket [
http://exploration.…bgmr.html ], but will continue with an innovative ion propulsion system [
http://dawn.jpl.nas…index.html ]. The spacecraft's extremely efficient ion engines [
http://science.nasa…] will use electricity derived from solar power to ionize xenon atoms and generate a gentle but continuous thrust. After a four year interplanetary cruise, Dawn will orbit two small worlds [
http://antwrp.gsfc.…], first Vesta and then Ceres. Vesta is one of the largest main belt asteroids, while nomenclature introduced by the International Astronomical Union in 2006 classifies nearly spherical Ceres as a dwarf planet [
http://solarsystem.…profile.cfm?Object=D warf&Display=Overvie wLong ].
Explanation
