U.S.-European Spacecraft Nears Goal of Saturn
June 30, 2004
After a nearly seven year journey, scientists in Europe and the United States are waiting with bated breath for the Cassini spacecraft to approach Saturn. The probe will have traveled 3.5 billion kilometers (2.2 billion miles), when it finally starts orbiting the ringed planet Thursday.
The critical moment, however, will come when Cassini is set to fire its engines after flying through a gap in Saturn's rings, starting at 2:36 UTC Thursday morning. That should use up 1.5 tons of fuel and slow the craft down enough for it to get caught in Saturn's gravity field and pulled into the planet's orbit.
But with a delay of more than an hour, scientists on the Earth will have no control over Cassini, which will have to manage the tricky maneuver without colliding with any potentially damaging space particles on its own. From there the probe will begin making 76 rounds of Saturn over a period of at least four years, collecting data and images of the planet, its rings and its moons.
"We're right on track," navigation team chief Jeremy Jones told a news conference Tuesday at NASA's Jet Propulsion Laboratory.
Cassini program manager Robert Mitchell and other officials expressed confidence that the craft would successfully enter Saturn's orbit, but he admitted that the procedure was a "hair-graying" event, AP reported.
Named after the French astronomer who in 1675 discovered Saturn's rings, Cassini is expected to start sending data and images from Saturn on Thursday.
Decades of work
The mission has been in the works for nearly 30 years and has cost NASA and the European Space Agency (ESA) $3.3 billion (€2.71 billion) and the energies of more than 5,000 scientists. Cassini, carrying the wok-shaped probe Huygens on its back, was sent into space from Cape Canaveral in Florida on October 1997.
Huygens, named after the Dutch astronomer who in 1659 first recognized the true shape of the ring around Saturn, is meant to explore Titan, the largest of the planet's 31 known moons. The craft is programmed to take leave of its host on Christmas and parachute into Titan's atmosphere.
The moon is particularly interesting to scientists because it's thought to have conditions similar to those on Earth before life emerged. Scientists estimate Huygens will have around one and a half hours to relay data from Titan's atmosphere before its battery runs out in the minus 180 degrees Celsius (minus 292 degrees Fahrenheit) weather.
"This is one of the most exciting projects we have going," David Southwood, ESA's director of science, told DW-WORLD."Huygens will be the first time Europe has landed in the outer solar system. And perhaps the most exciting thing of all is that we don't know whether it's going to land or splash down, because Titan is swathed in a thick, smoggy atmosphere and we can't see its surface. It may have methane oceans."