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Destination: SpaceThere's a lot of spaceflight action on tap this year. NASA's venerable Cassini Saturn mission will come to a dramatic end, a new exoplanet-hunting mission is scheduled to lift off and private spaceflight will likely take a number of exciting steps forward.
Here's Space.com's look at what we expect to be the 10 most important spaceflight stories of 2017. [Read about 2016's biggest spaceflight stories]
Cassini's grand finaleSlide 2 of 22
Cassini's grand finaleCassini, which has been orbiting Saturn since July 2004, will perform a dramatic death dive into the gas giant's thick atmosphere on Sept. 15. This suicidal plunge will wrap up the "Grand Finale" phase of Cassini's mission: a series of 22 orbits that will take the probe between Saturn and its innermost ring. The first such close flyby will take place on April 22.
The $3.2 billion Cassini-Huygens mission, a joint effort of NASA, the European Space Agency and the Italian Space Agency, launched in October 1997. The Cassini mothership carried a lander called Huygens, which touched down on Saturn's largest moon, Titan, in January 2005.
Cassini continued circling Saturn, studying the huge planet, its rings and many moons. Cassini has made many important discoveries over the years; for instance, the probe spotted liquid-hydrocarbon lakes on Titan and geysers of water ice blasting from the south polar region of the Saturn moon Enceladus. [Ocean on Saturn Moon Enceladus Suspected Beneath Ice (Video)]
Cassini's death plunge is designed to ensure that the spacecraft doesn't contaminate Titan or Enceladus, — both of which may be capable of supporting life — with microbes from Earth, NASA officials have said.Slide 3 of 22
Dawn's mission coming to a closeSlide 4 of 22
Dawn's mission coming to a closeNASA's Dawn spacecraft is also nearing the end of the road, though its final days won't be as dramatic as Cassini's.
The $467 million Dawn mission launched in September 2007 to study Vesta and Ceres, the two largest objects in the main asteroid belt between Mars and Jupiter. The spacecraft circled Vesta from July 2011 through September 2012 and reached the dwarf planet Ceres in March 2015, in the process becoming the first probe ever to orbit two bodies beyond the Earth-moon system.
Dawn's observations have revealed a great deal about dry, rocky Vesta and icy Ceres. The probe famously spotted mysterious bright spots within several Ceres craters, for example, and found evidence that water ice is common just beneath the dwarf planet's surface.
Dawn is currently operating on an extended mission, after wrapping up its primary mission in June 2016. But the spacecraft's fuel supplies are low and will likely run out sometime this year, mission team members have said. After Dawn is shut down, the spacecraft will continue orbiting Ceres as an artificial satellite of the dwarf planet indefinitely.Slide 5 of 22
Private moon race in home stretchSlide 6 of 22
Private moon race in home stretchIt's go time for the teams that are still trying to win the $30 million Google Lunar X Prize (GLXP).
GLXP's organizers are offering $20 million to the first privately funded team to land a spacecraft on the moon, have it travel at least 1,650 feet (500 meters) on the lunar surface and beam high-definition photos and video back to Earth. Another $5 million goes to the second team to achieve these tasks, and $5 million more is available for other accomplishments, such as finding water ice on the moon.
Teams have until Dec. 31, 2017, to claim the prize. Five teams remain in the running: Israel-based SpaceIL, Moon Express from the U.S., India-based Team Indus, Hakuto from Japan and the international team Synergy Moon.Slide 7 of 22
Falcon Heavy's maiden launchSlide 8 of 22