Extraordinary performance and accuracy have marked the first hours of the Cassini spacecraft's long journey to Saturn. Cassini left Earth in a flawless launch at 4:43 a.m. EDT (1:43 a.m. PDT), rocketed into a moonlit sky above Cape Canaveral, FL. Performance of the launch vehicle, Centaur upper stage and the spacecraft itself were "right on the money," said Cassini program manager Richard J. Spehalski of JPL.
The energy provided to the spacecraft by its Titan IV/B Centaur launch vehicle was accurate to within one part in 5,000. The angular deviation in the trajectory was described as "insignificant" at better than .004 degrees. Mission plans called for an expected adjustment in Cassini's post-launch trajectory of about 26 meters per second, but flight data shows a mere one meter per second correction will be required in Cassini's first scheduled trajectory correction maneuver, Spehalski said. All systems on the spacecraft were operating normally, he reported.
Cassini's 4-meter (13-foot) diameter high-gain antenna is correctly pointed toward the Sun, serving as a parasol to shade the spacecraft during its travels through the inner solar system. The JPL-built orbiter will fly a circuitous route to reach Saturn, performing two gravity-assist swingbys of Venus, one of Earth and one of Jupiter to gain enough speed to reach Saturn, which is 1.4 billion kilometers (nearly 1 billion miles) from the Sun.
In the next couple of days, Cassini will perform various routine housekeeping activities to ensure that instrument optics are not contaminated by outgassing of vapors that occurs in a spacecraft's first hours in space. Cassini is also scheduled to play back telemetry it recorded on its solid state recorder during launch. The data will provide a detailed look at how all of the spacecraft subsystems performed during the launch phase. Cassini is traveling at a velocity of about 13,000 kilometers per hour (about 21,000 miles per hour) relative to Earth. Early activities included the deployment of the Langmuir probe. Scheduled activities include the release of several latches that secured instrument covers and other deployable devices through the launch phase. In two days, ground controllers at JPL will send to Cassini the sequence of computer commands to control the spacecraft for the following week.
European Space Agency
Press Release No. 32-97
Paris, France
ESA's latest and farthest venture into the Solar System began at 10:43 Paris time on 15 October. The American Titan IVB/Centaur launcher sent NASA's large Cassini spacecraft on its way to Saturn. Cassini carries ESA's probe Huygens, as well as the high-gain antenna provided by ASI, the Italian Space Agency. In 2004 ESA's Huygens probe will plunge into the thick atmosphere of Saturn's largest moon, Titan.
About 500 representatives of the scientific, engineering and industrial teams in Europe, which created the Huygens Probe, were present at Cape Canaveral for the Cassini Huygens launch. They saw the powerful boosters of the Titan launcher light up the pre-dawn sky.
The launch sequence concluded with the completion of the second firing and separation of the Centaur upper stage rocket. NASA's ground station at Canberra, Australia, obtained good signals from Cassini an hour after launch.
The European Space Operations Centre (ESOC) at Darmstadt will monitor the condition of the Huygens spacecraft. Their report is expected in 8-10 days' time.
The next major event will be the swingby of Cassini Huygens at Venus on 21 April 1998. This is the first of a sequence of "gravity-assist" operations at Venus, the Earth and Jupiter, to accelerate the spacecraft.