Because Huygens will stay dormant until it arrives at Titan, how do we know it separated successfully and is on course?
Fortunately, the mission’s engineers do have some data to go on. Telemetry from Cassini confirmed that the pyrotechnic devices were fired to release Huygens, and that the orbiter’s attitude had indeed varied as expected in response to the probe’s release.

Cassini’s cameras also checked out Huygens’ release velocity and direction, and data confirmed that it was spinning correctly. The spin imparted to Huygens is vitally important to ensure it remains in a stable attitude and on course when it enters Titan’s atmosphere. The spin rate was determined by measuring changes in the probe’s magnetic field.

^{Left, artist’s view of Huygens moving away from Cassini. Credits: ESA-D. Ducros
Right, Huygens seen by Cassini’s cameras. Credits: NASA/JPL}

Huygens will reach its destination on Friday 14 January 2005. Its instruments will be switched on a few hours before entering Titan’s atmosphere, where they will acquire data for more than 2 hours. Huygens will be the first explorer spacecraft to conduct in-situ measurements of Saturn’s largest moon, relaying a wealth of data back to Earth via the Cassini orbiter.

The 1st pictures will reach us after 68 minutes and are expected in the afternoon. You can watch events unfold live from the Collège de la Cité des Sciences in Paris at a special evening co-organized with CNES, the Société Astronomique de France and the European Space Agency (ESA), in the company of scientists in Paris and at ESA’s control centre in Darmstadt, Germany.

Entry to the Auditorium at the Cité des Sciences et de l'Industrie is free, with seating on a first-come-first-served basis.