( CNN ) NASA 's tractor-trailer sized Dawn spacecraft will snuggle up to Ceres on Friday , getting close enough to be pulled into orbit and to complete the first mission to a dwarf planet . `` I 'm just delighted that Dawn is now on the doorstep of Ceres , '' Jim Green , director of NASA 's planetary science division said in a news conference on Monday . Dawn is expected to begin orbiting Ceres around 7:20 a.m . ET , but NASA says it may take an hour or two to confirm it . Ceres was discovered in 1801 ( Pluto was n't found until 1930 ) and was the first object found in our solar system 's main asteroid belt between Mars and Jupiter . It 's about 310 million miles from Earth and was initially classified as planet , then later demoted to an asteroid , only to be reclassified again as a dwarf planet . The early images from Dawn already have mission scientists excited . `` Ceres has really surprised us , '' said Carol Raymond , Dawn 's deputy principal investigator . `` The first images have produced some really puzzling features . '' One of the puzzles -- two bright white spots that showed up in photographs taken by Dawn in February . `` These spots were extremely surprising to the team , and they have been puzzling to the team and to everybody who 's seen them . '' The spots are in a 57-mile wide ( 92 kilometer ) crater . The spot in the center of the crater is about twice as bright as the spot on the side of the crater . `` This extreme brightness was really unexpected , '' Raymond said . The Dawn team is `` really , really excited about this feature because it is unique in the solar system . '' Raymond says the brightness is consistent with highly reflective materials such as ice or salts . This might help add more credence to a discovery made in 2014 by ESA 's Herschel infrared space observatory . The telescope detected water vapor around Ceres coming from the same area where the spots are located . `` It might be related to that water vapor emission , '' Raymond said . Herschel 's scientists also said their research showed Ceres has an atmosphere . Raymond said her team is keen to confirm that . Scientists expect to learn more as Dawn is gradually lowered to about 235 miles above the surface of Ceres in December . `` The mystery will be solved , '' she said . But Ceres seems to have lots of oddities . `` We see many strange features , '' Raymond said . `` We see smooth areas , some areas that are chaotically fractured and we see craters of all sizes . '' One of the other things scientists noticed is how round Ceres is . Being round is very important because it is the main characteristic of a planet -- a title that Ceres had -- then lost . Ceres was demoted to an asteroid because 19th century astronomers could n't be sure it was round . But it was bumped up to a dwarf planet when that category was created in 2006 . According to the International Astronomical Union -- the group that came up with the definition -- a dwarf planet is similar to the eight main planets ( Mercury , Venus , Earth , Mars , Jupiter , Saturn , Uranus and Neptune ) except it has a lot of other stuff orbiting with it around the sun . The IAU recognizes five dwarf planets : Eris , Pluto , Ceres , Makemake and Haumea . Scientists say there could be many more of these small worlds that have n't been discovered . Dawn was launched on September 27 , 2007 , from Cape Canaveral , Florida . Its journey has taken it past Mars and on a short layover at the asteroid Vesta . On Friday , Dawn will make its closest approach yet to Ceres , flying about 25,000 miles from it , according to Robert Mase , project manager for the Dawn mission at NASA 's Jet Propulsion Laboratory in Pasadena , California . `` That 's about 10 times closer than the moon is to the Earth , '' he said . But the beautiful images coming in from Dawn will stop for awhile . `` We 're now on the dark side , so we 're going to have a blackout for about the next month until we get back over toward the lit side of the body , '' he said . But he says the `` floodgates will open '' when its main science mission starts in April . Dawn will stay in orbit around Ceres for years , even after its primary mission ends in June 2016 . But at some point , it will run out of hydrazine , the fuel used to guide the spacecraft . Between now and then -- mission managers hope Dawn will help solve the mysteries of Ceres and add to our knowledge of how our solar system formed .
NASA 's Dawn spacecraft arrives the next month at Ceres . The spacecraft is the first to visit a dwarf planet .