Liftoff of the Cassini Spacecraft
October 15, 1997
6 a.m. EDT
The international Cassini spacecraft mission left Earth bound for Saturn this morning atop an Air Force Titan IV/B Centaur rocket in a picture-perfect launch at 4:43 a.m. EDT (1:43 a.m. PDT) from Cape Canaveral, FL.
On time and on schedule for today's launch opportunity, the Titan solid rocket boosters ignited at the opening of today's launch window, setting the Cassini spacecraft on its nearly seven-year journey to the ringed planet. All milestones during the rocket's ascent occurred as planned, culminating with a successful separation of the Centaur upper stage from the Cassini spacecraft at 42 minutes and 40 seconds into flight. Flying on its own for the first time, the Cassini spacecraft opened its communications link with the NASA Deep Space Network communications complex near Canberra, Australia, about 10 minutes later, or about 52 minutes post launch.
With the European Space Agency's Huygens probe onboard and communicating through a high-gain antenna provided by the Italian Space Agency, Cassini will arrive at Saturn July 1, 2004. The JPL-built Cassini orbiter flies a circuitous but necessary route to reach Saturn. The spacecraft will perform 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.
9 a.m. EDT
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 5.05 kilometers per second (about 11,310 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.
Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.
Cassini will begin orbiting Saturn on July 1, 2004, and release its piggybacked Huygens probe about six months later for descent through the thick atmosphere of the moon Titan. Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Office of Space Science, Washington, D.C.