Goals: The 318 kg (852 pound) probe was designed to study the smog-like atmosphere of Saturn's largest moon Titan as it parachuted to the surface. It also carried cameras to photograph the moon's surface. Huygen's traveled to Saturn aboard NASA's Cassini orbiter.
Accomplishments: The Huygens probe successfully touched down on Titan in January 2005 -- the first spacecraft landing in the outer solar system and the farthest from Earth. The probe provided a detailed study Titan's atmosphere during a 2 hour and 27 minute descent and relayed data and images from Titan's muddy surface for another hour and 10 minutes.
15 Oct 1997: Launch
14 Jan 2005: Titan Landing
Mission Type: Lander
Launch Vehicle: Titan IVB/ Centaur
Launch Site: Cape Canaveral Air Force Station, Fla., USA
Spacecraft Mass: 318 kg
Spacecraft Instruments: 1) Aerosol Collector and Pyrolyser; 2) Descent Imager and Spectral Radiometer; 3) Doppler Wind Experiment; 4) Gas Chromograph and Mass Spectrometer; 5) Huygens Atmospheric Structure Instrument; and 6) Surface Science Package.
- European Space Agency, Cassini-Huygens Mission Profile, http://sci.esa.int/science-e/www/area/index.cfm?fareaid=12
- Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi
- National Space Science Data Center, http://nssdc.gsfc.nasa.gov/
- Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.
ESA's Huygens Probe was delivered to Titan by the Cassini Orbiter in January 2005 after a dormant interplanetary journey of 6.7 years.
The probe started its descent through Titan's hazy cloud layers from an altitude of about 1,270 km. Huygens had to decelerate from 18,000 to 1,400 km per hour. A sequence of parachutes then slowed it down to less than 300 km per hour. At a height of about 160 km the probe's scientific instruments were exposed to Titan's atmosphere and at about 120 km the main parachute was replaced by a smaller one to complete the 2.25 hour descent.
The probe descended through haze until an altitude of about 30 km above the surface. This was around half the altitude suggested by pre-mission estimates of between 70 to 50 km above the surface.
At an altitude of 700 meters above the surface the descent lamp was activated. The purpose of this lamp was to not to illuminate the landing site, the light levels on the surface of Titan are roughly 1,000 times less than sunlight and 1,000 times stronger than a full moon, but to provide a monochromatic light source and enable scientists to accurately determine the reflectivity of the surface.
The surface phase of the mission lasted 1 hour and 10 minutes - considerably longer than had been anticipated. The landing on the surface was soft meaning no damage was done to the probe.