Dawn is on the threshold of a new world. After more than three and a half years of interplanetary travel covering in excess of 2.6 billion kilometers (1.6 billion miles), we are closing in on our first destination. Dawn is starting its approach to Vesta.
Three and a half years after launch, Dawn continues its travels around the Sun, maneuvering to take the same orbital path as Vesta. The spacecraft has spent most of the past month gently thrusting with its ion propulsion system. Some of the thrusting this month, however, was not designed to propel Dawn to Vesta.
Regular readers of this blog will find the content of today's 365 Days of Astronomy Podcast familiar, because it's an update on what the solar system exploration spacecraft are up to, based on my monthly "what's up" updates.
April 2011 will see MESSENGER begin the science phase of its orbital mission at Mercury, and should, I think, also see the start of Dawn's approach observations of Vesta. At Mars, Opportunity is back on the road again, rolling inexorably toward Endeavour. At Saturn, Cassini will continue its focus on Saturn and Titan science.
Today the Dawn imaging team released a photo from the main camera, the Framing Camera, symbolizing that they're preparing to start Dawn approach science; the other two science instruments, a spectrometer and a neutron detector, are also being turned on and checked out.
Deep in the asteroid belt, Dawn continues thrusting with its ion propulsion system. The spacecraft is making excellent progress in reshaping its orbit around the sun to match that of its destination, the unexplored world Vesta, with arrival now less than five months away.
Dawn continues its flight through the asteroid belt, steadily heading toward its July rendezvous with Vesta, where it will take up residence for a year. On January 10, Dawn performed some of the activities that it will execute in its low altitude mapping orbit (LAMO) at Vesta.
Dawn is now so far from the sun that even with its tremendous solar arrays, it does not receive enough sunlight to generate sufficient electrical power to operate all systems and still achieve maximum thrust.