Australian telescopes to
take part in Huygens
9 Dec 2004
On 14 January, radio telescopes of CSIRO and other Australian institutions will help pinpoint the location of the European Space Agency's Huygens probe as it plunges through the clouds of Titan, Saturn's largest moon.
The goal is to measure the speed of the winds in Titan's atmosphere.
This experiment is being coordinated by JIVE, the Joint Institute for VLBI in Europe. It is separate from the tracking of the probe's parent Cassini spacecraft, which will be done by NASA’s Deep Space Communication Network, including the Canberra Deep Space Communications Complex at Tidbinbilla, ACT.
Shortly after 9 pm AEDT the probe will start its descent through the clouds of Titan, 1.2 billion kilometres from Earth. Using a special technique, a network of 17 radio telescopes in Australia, the USA, China and Japan will attempt to determine its entry point to within a kilometre.
The radio telescopes taking part in Australia are the CSIRO telescopes near Parkes, Narrabri and Coonabarabran (all in NSW) and telescopes of the University of Tasmania near Hobart and Ceduna (South Australia).
As it parachutes through Titan's clouds the Huygens probe will transmit data to the Cassini orbiter. The ground-based telescopes will eavesdrop on this transmission.
"The signal will be extremely weak - about as weak as a signal from a mobile phone on Venus would be," says CSIRO's Dr Chris Phillips, who is coordinating the Australian observations.
The Parkes telescope will be particularly important in the network because of its large size, which makes it ideal for collecting weak signals.
Parkes will also be used for a separate, extra experiment, to determine the position of the probe by measuring the Doppler shift of its signal.
Information on the probe's position from these experiments will be combined with data from the Cassini orbiter and used to calculate the speed of the winds in Titan's atmosphere.
Titan is the second-largest moon in our Solar System, with a diameter about one-and-a-half times that of our Moon. It has a thick atmosphere, and is thought to harbour organic compounds that might be important in the formation of life.
Seventeen countries are contributing to the Cassini-Huygens mission. The Huygens probe is supplied by the European Space Agency (ESA) and the Cassini orbiter by NASA. Huygens operations will be controlled by ESA from its operations centre in Darmstadt, Germany. NASA is providing the mission operations and telecommunications through its Deep Space Network of antennas, which includes the Canberra Deep Space Communications Complex at Tidbinbilla.
The US-based telescopes taking part in the experiment belong to the Very Long Baseline Array (VLBA) operated by the National Radio Astronomy Observatory (NRAO). NRAO is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
Dr Chris Phillips, Bolton Fellow, CSIRO Australia Telescope National Facility
Dr John Reynolds, Officer-in-Charge, CSIRO Parkes Observatory
Professor John Dickey, University of Tasmania
Dr Leonid Gurvits, Project Manager, Huygens VLBI tracking experiment
Joint Institute for VLBI in Europe, Dwingeloo, The Netherlands
Office: +31 (0)521 596514
Dr Rosemary Mardling, Centre for Stellar and Planetary Astrophysics, Monash University
(Dr Mardling's interest in Titan is related to how the Solar System was formed, and in particular whether or not Titan is a captured satellite of Saturn.)
Office 03 9905-4506
Mobile 0409 808 218
ESA’s Cassini-Huygens website
NASA’s Cassini-Huygens website
ESA-TV will broadcast Huygen's descent into Titan live on 14/15 January.
Details of the broadcast will be posted at http://television.esa.int in early January.