Posted: Sat, Jun 30, 2001, 10:30 AM ET (1430 GMT)
The Cassini mission to Saturn will be altered slightly to handle problems with the Huygens drop probe, NASA and ESA officials confirmed Friday. The deployment of Huygens into the atmosphere of the moon Titan will be delayed seven weeks from November 2004 to January 14, 2005, and the flyby distance of Cassini to Titan will be moved to 65,000 kilometers, compared to 1,200 km previously planned. The changes were required when engineers discovered last year that the antenna on the European-built Huygens did not properly compensate for changes in its transmission frequency caused by Doppler shift. Without the changes to the mission Cassini would have been unable to receive most of the data transmitted by Huygens during its several-hour descent through Titan's atmosphere. The changes will allow the mission to meet its scientific objectives but will cost Cassini one-fourth to one-third of its reserve propellant, designed to be used both for contingencies like this as well as an extended mission when Cassini's primary mission ends in 2008. News of the change was first reported a week and a half earlier by the Associated Press, who at the time reported that Huygens' deployment would be delayed until March 2005.

Related Links:

•  NASA press release
•  Cassini
•  Huygens