October 6, 1997. Copyright, 1997, Graphic News. All rights 
reserved 

CASSINI Ð LAST OF THE GRAND SPACECRAFT
By Lis Ribbans

CASSINI, the largest and most sophisticated interplanetary 
spacecraft ever built, is scheduled to blast off from Cape 
Canaveral on October 13, at 4.55 EDT, on a 2.1 billion-mile 
(3.5bn km) journey to the ringed planet, Saturn.

The 6-ton (5,650kg) robotic probe Ð developed by Nasa, ESA and 
the Italian Space Agency Ð cannot be launched with sufficient 
speed to head straight for Saturn. Instead, it is set on a 
trajectory that involves two flypasts of Venus, then Earth and 
Jupiter, allowing it to ÔstealÕ enough speed from their 
gravitational fields to reach Saturn by June 2004.

It will then spend four years gathering data on the solar 
systemÕs second largest planet, its rings, magnetic environment 
and icy satellites. A sub-probe, Huygens, will be dropped by 
parachute on to the largest moon, Titan, which with a diameter of 
3,200 miles (5,150km) is slightly larger than Mercury.

It is hoped the information Cassini sends home, enough to fill 
300 CD-Roms, will provide clues to the creation of the solar 
system and pre-life conditions on Earth.

Environmentalists have been lobbying President Clinton to cancel 
the mission amid fears that the 72lbs (32.6kg) of plutonium on 
board Ð the largest amount of the radioactive energy source ever 
carried by a U.S. spacecraft Ð could contaminate Earth in the 
event of a launch-pad accident. The Titan IV rocket that will 
launch the probe has a five percent failure rate but scientists 
estimate that when the chances of a leak are taken into account, 
the risk factor is one percent. Because Saturn is 886 million 
miles (1.4bn km) from the sun, solar energy is impractical.

The mission, which at a cost of around U.S.$3.4bn is expected to 
be NasaÕs last large-scale interplanetary project, is named after 
the 17th-century Italian-born French astronomer Giovanni Domenico 
Cassini, who discovered the gap that divides SaturnÕs rings into 
two parts.

/ENDS  
Sources: ESA, Aviation Week and Space Technology, Associated Press