ALICE arrives in Italy
20 July 2001A miniaturised experiment that will help to unveil the mysteries of a comet is the latest of the instruments that will fly on ESA's Rosetta Orbiter to be delivered to Italy. The ALICE ultraviolet (UV) spectrometer, which arrived at the Turin plant of Alenia Spazio earlier this week, has already been tested and integrated on the Rosetta spacecraft.
ALICE is scheduled to be the first ultraviolet spectrometer to study a comet up close. It was designed and built by Southwest Research Institute (SwRI) in Boulder, Colorado, with optics contributed by France, and is the first in a new generation of UV spectrometers that weigh less and require far less power than previous instruments of their kind. Its development was triggered in the mid-1990s by NASA's push to miniaturise scientific instruments for future planetary missions.
The shoebox-sized ALICE is one-third to one-half the mass of comparable UV spectrometers. After advanced laboratory development in support of Pluto mission concept studies, ALICE was proposed and selected for development on Rosetta by NASA and ESA in 1996. A more sophisticated version of ALICE has been proposed for NASA's hoped-for Pluto-Kuiper Belt mission.
"ALICE is a revolutionary instrument," said Dr. S. Alan Stern, director of the SwRI Space Studies Department and principal investigator for the ALICE instrument. "It will reveal new insights into the origin, composition, and workings of comets - insights that cannot be obtained by either ground-based or Earth-orbital observations."
"Although UV spectrometers in Earth orbit have studied comets for many years, ALICE will offer both unprecedented spatial resolution and unrivalled spectral sensitivity," said Stern.
The instrument features an advanced 'micro-channel plate' detector, sophisticated optics, a miniaturised 6,000-volt power supply, and operates on just 3 watts.
"The Rosetta mission has to operate out to 5 AU where the Sun is only 4 percent as bright as it is here on Earth. That means that each instrument must do their part to be very efficient," said ALICE Project Manager John Scherrer, also of SwRI. (One AU or astronomical unit is the average distance from the Sun to the Earth - approximately 150 million km.)
"Although ALICE is the first interplanetary UV spectrometer developed at SwRI, its development went smoothly, and its performance meets and even exceeds its original design specifications. It's going to be very exciting to see it returning data in flight," said Dr. James Burch, vice president of the SwRI Space Science and Engineering Division.
The ALICE science team includes prominent comet scientists from France, the University of Maryland, and Johns Hopkins University.
For further information contact:
SwRI press office
Tel: +1 210-522-3305
Dr. Alan Stern
ALICE Project Scientist
Tel.: +1 303-546-9670