Titan -- Up Close and Personal -- UK scientists comment on flyby


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Cassini-Huygens, the joint NASA/ESA/ASI space mission has successfully made a close encounter with Saturn's moon, Titan. This was confirmed in the early hours of this morning as the first information and pictures were beamed back via NASA's Deep Space Network tracking station in Madrid, Spain. As anticipated, the spacecraft came within 1,200 kilometres (750 miles) of Titan's surface.

The first images

At the time, Cassini was about 1.3 billion kilometres (826 million miles) from Earth. Numerous images, perhaps as many as 500, were taken by the visible light camera and were being transmitted back to Earth. It takes 1 hour and 14 minutes for the images to travel from the spacecraft to Earth. The downlink of data will continue through the night into the early morning hours. Cassini project engineers will continue to keep a close watch on a rainstorm in Spain, which may interrupt the flow of data from the spacecraft.

Professor Carl Murray from Queen Mary, University of London, a member of the Cassini Imaging Science Subsystem team, has been taking a look at the first images,

"Titan's veil has been lifted yet again and we have been treated to a spectacular array of images from this bizarre moon. The return of this data from such a peculiar and distant world is another remarkable success for Cassini. When the images are combined with data from the other instruments on Cassini we will have a much more complete understanding of what the Huygens probe can expect when it lands in January."

The flyby was by far the closest any spacecraft has ever come to Titan, the largest moon of Saturn, perpetually drenched in a thick blanket of smog. Titan is a prime target of the Cassini-Huygens mission because it is the only moon in our solar system with an atmosphere. It is a cosmic time capsule that offers a look back in time to see what Earth might have been like before the appearance of life.

Mark Leese, is a member of the Huygens team at the Open University, who are involved in the Science Surface Package (SSP) and the Huygens Atmospheric Instrument (HASI).

"The Open University Huygens team are looking forward to what these images and other data may tell us about the surface of Titan, in anticipation of the Huygens mission on January 14th 2005. Then we hope that the UK built Surface Science Package will send back the first measurements from the surface of Titan."

He adds, "The combination of images, spectrometer measurements and RADAR data from this close flyby should help to prepare us for the mission ahead. In addition, Cassini's measurements of the atmosphere should confirm that the Titan atmosphere model used to design the probe entry system is correct."

The Huygens probe, built and operated by the European Space Agency, is attached to Cassini; its release is planned on Christmas Day. It will descend through Titan's opaque atmosphere on January 14, 2005, to collect data and touch down on the surface.

UK scientists are playing significant roles in the Cassini Huygens mission with involvement in 6 of the 12 instruments onboard the Cassini orbiter and 2 of the 6 instruments on the Huygens probe. The UK has the lead role in the magnetometer instrument on Cassini (Imperial College) and the Surface Science Package on Huygens (Open University).

Notes to Editors:

Further NASA briefings and coverage

Details of the NASA TV coverage of the flyby and results, http://www.nasa.gov/multimedia/nasatv/MM_NTV_Breaking.html

UK Science and Industrial Involvement

UK scientists are playing significant roles in the Cassini Huygens mission with involvement in 6 of the 12 instruments onboard the Cassini orbiter and 2 of the 6 instruments on the Huygens probe. The UK has the lead role in the magnetometer instrument on Cassini (Imperial College) and the Surface Science Package on Huygens (Open University).

UK industry had developed many of the key systems for the Huygens probe, including the flight software (LogicaCMG) and parachutes (Martin Baker). These mission critical systems need to perform reliably in some of the most challenging and remote environments ever attempted by a man made object. For examples, the Huygens probe will hit the atmosphere of Titan at 6 km/sec. LogicaCMG's software onboard the probe will be responsible for deploying the parachutes, separating the front and back shield with precise timings to achieve the required descent profile; reducing the velocity of Huygens before commencing the science experiments, and managing communications back to Cassini.

Titan Background

Titan is a highly complex world and is closer to a terrestrial planet than a moon typical of the outer planetary systems. Titan was first seen by Dutch astronomer Christiaan Huygens (after which the ESA probe is named) in 1655.

Not only is Titan the largest of Saturn's satellites, it is also larger than the planets Mercury and Pluto, and is the second largest satellite in the solar system (Jupiter's Ganymede being larger). It is the only satellite in the solar system with appreciable atmosphere, composed mostly of Nitrogen, but also contains aerosols and hydrocarbons, including methane and ethane. Titan's atmosphere was first confirmed in 1944 when Gerard Kuiper confirmed the presence of gaseous methane with spectroscopy.

Titan's peak surface temperature is about 95 K (-178 degrees C) and surface pressure is 1.6 Earth atmospheres. At this temperature and pressure, many simple chemicals that are present in abundance (methane, ethane, water, ammonia) provide materials in solid, liquid and gaseous form which may interact to create exotic features on the surface. Precipitation, flowing liquids, lakes and eruptions are all possible.

Titan orbits Saturn at a distance of just over 20 Saturn radii (1,222,000 km/759,000 miles) which is far enough to carry the moon in and out of Saturn's magnetosphere. Very little is known about Titan's interior structure, including whether it has its own magnetic field.

Titan's surface has been difficult to study, as it is veiled by a dense hydrocarbon haze that forms in the dense stratosphere as methane is destroyed by sunlight. From the data collected so far, dark features can be seen crossing the equatorial region of Titan, with a large bright region near longitude 90 degrees now named Xanadu, and possibly a large crater in the northern hemisphere.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.

The Particle Physics and Astronomy Research Council (PPARC) is the UK's strategic science investment agency. It funds research, education and public understanding in four broad areas of science -- particle physics, astronomy, cosmology and space science.

PPARC is government funded and provides research grants and studentships to scientists in British universities, gives researchers access to world-class facilities and funds the UK membership of international bodies such as the European Organisation for Nuclear Research, CERN, the European Space Agency and the European Southern Observatory. It also contributes money for the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, the UK Astronomy Technology Centre at the Royal Observatory, Edinburgh and the MERLIN/VLBI National Facility.

Crew Resumes Full Work Schedule

Expedition 10 Commander Leroy Chiao and Flight Engineer Salizhan Sharipov returned to a full workload Wednesday aboard the International Space Station. Chiao and Sharipov received three days of light duty after eight days of joint operations with Expedition 9 Commander Gennady Padalka and NASA ISS Science Officer Mike Fincke. Expedition 10 became the resident crew Saturday with the departure of Expedition 9.

Wednesday's activities included checkout of a gas analyzer system in the Station's Human Research Facility and the installation of new software onto the medical equipment computer.

Also, both crewmembers participated in a standard familiarization session that is conducted every day during the first two weeks of a new crew's stay on the ISS.

On the ground, Padalka and Fincke are in Star City, Russia, for several weeks of post-flight debriefings and medical exams before returning to Houston in mid-November.

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