Press Release

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

By SpaceRef Editor
October 28, 2004
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Titan — Up Close and Personal — UK scientists comment on flyby

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,

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.

SpaceRef staff editor.