PASADENA, California Ė The National Aeronautics and Space Administrationís Cassini space probe completed its extraordinary journey of exploration on Friday and ended its mission almost 20 years after takeoff by taking a final, fiery plunge at high speed into Saturnís atmosphere, NASAís Jet Propulsion Laboratory in Pasadena, California said.
Cassini had spent the last 13 years circling around Saturní s ring and satellite system, busily transmitting data and images right to the last second prior to destruction in the gas giantís outer reaches.
ďAfter two decades in space, NASAís Cassini spacecraft is nearing the end of its remarkable journey,Ē NASA said. ďHaving expended almost every bit of the rocket propellant it carried to Saturn, operators are deliberately plunging Cassini into the planet to ensure Saturnís moons will remain pristine for future exploration,Ē the statement added.
Scientists had been eager to keep Saturnís moons, in particular Enceladus, as well as other space objects, uncontaminated.
Cassiniís last orbit came after a final 22 weeks of orbital dives, hurtling through a gap between Saturn and its rings, that began in April.
No spacecraft had ever ventured so close to the gas giant.
NASAís JPL Mission Controlís final calculations predicted the loss of contact with Cassini would take place Sept. 15 at 4:55 am local time.
Cassini would have entered Saturnís atmosphere one minute earlier, some 1,190 miles (1,915 kilometers) above the planetís cloud tops at around 70,000 mph (113,000 km/h).
When Cassini encountered Saturnís upper atmosphere, its control thrusters fired in short bursts attempting to keep its saucer-shaped high-gain antenna pointed towards Earth to relay the missionís final data.
As the atmosphere thickened, its thrusters went from 10 percent capacity to full power in around a minute.
At that point, the spacecraft was no longer capable of fighting Saturnís dense atmosphere and tumbled, spinning out of control.
As soon as the antenna swayed some fractions of a degree away from Earth, all communications were cut for good.
NASA predicted this would happen at some 930 miles (1,500 km) above Saturnís cloud tops and the spacecraft became a meteor.
It was calculated that Cassini began disintegrating 30 seconds later.
NASA scientists would only get confirmation of events 83 minutes after they occurred, given that is how long radio signals take to reach mission control.
Earl Maize, Cassini project manager previously explained the spacecraftís final signal would be its swan song: ďIt isnít truly over for us on Earth as long as weíre still receiving its signal.Ē
Cassiniís last data relays were picked up by NASAís Deep Space Network complex in Canberra, Australia.
Cassini was expected to provide groundbreaking scientific observations of Saturn, with eight of its 12 science instruments collecting pioneering data in the final plunge, sampling the planetís atmosphereís composition and structure.
Before Cassini, the only brief glimpses of Saturn were the Pioneer 11 and Voyagers 1 and 2 flybys decades ago. They briefly took pictures and data as they zoomed past.
These missions gave us insights on Saturnís complex ring system, discovering new moons and took sketchy measurements of Saturnís magnetosphere, but that was all.
Cassini changed all that when in 2004 it relayed new and surprising data, especially relating to Saturnís moons.
Cassiniís visit to Saturnís largest moon, Titan, gave scientists a glimpse of what Earth may have looked like before life evolved.
Also noteworthy was the data provided by the European Space Agencyís Huygens probe, which rode piggyback on Cassini all the way to Saturn before plunging in 2005 through Titanís dense atmosphere and landing on its surface.
Enceladus was another gem: A spray of icy particles from surface jets forming massive plumes extending way above Enceladus.
The spacecraft came as close as 15 miles (25 km) from its icy surface revealing the presence of a global subsurface ocean and conditions that may prove suitable for life.
Cassini cannot ďrustĒ in peace, after its incendiary demise but has earned a place of honor in NASAís hall of (robotic) fame, and changed the course of our future planetary exploration, the space agency said.