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NASA's Dawn Spacecraft Becomes First To Orbit a Dwarf Planet
The Grim Reefer writes with news that at 7:39 AM EST (12:39 UTC) today, NASA's Dawn spacecraft was captured by the gravity of dwarf planet Ceres.
Mission controllers at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California received a signal from the spacecraft at 5:36 a.m. PST (8:36 a.m. EST) that Dawn was healthy and thrusting with its ion engine, the indicator Dawn had entered orbit as planned. "Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet," said Marc Rayman, Dawn chief engineer and mission director at JPL. "Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls Ceres home." In addition to being the first spacecraft to visit a dwarf planet, Dawn also has the distinction of being the first mission to orbit two extraterrestrial targets. From 2011 to 2012, the spacecraft explored the giant asteroid Vesta, delivering new insights and thousands of images from that distant world. Ceres and Vesta are the two most massive residents of our solar system's main asteroid belt between Mars and Jupiter.
Further details available from the Planetary Society.
Ceres gravity is 0.27 m/s2 (Earth's is 9.8, Luna is a hefty 1.6)
So 'going into orbit' of something so vanishingly weak is really an amazing accomplishment, discussed in their blog at http://www.planetary.org/blogs....
(Amusing point of reference, with 3 ion engines, Dawn's 0-60 speed is 11 days. Take that, Jeremy Clarkson!)
Congrats all.
-Styopa
"Has to have cleared orbit". Even if Earth or any other rocky planet put where Ceres or Pluto was, they couldn't clear that orbit.
They're planets. "Dwarf planet" is an invention of morons, 95 percent of the astronomers in the IAU didn't vote on it because of when the vote was done.