Artist's impression of the Rosetta orbiter at comet
67P/Churyumov-Gerasimenko. The image is not to scale.
Image Credit:
ESA/ATG Medialab
A
NASA instrument aboard the European Space Agency’s (ESA's) Rosetta orbiter has
successfully made its first delivery of science data from comet
67P/Churyumov-Gerasimenko.
The instrument, named Alice, began mapping the comet’s surface last month,
recording the first far-ultraviolet light spectra of the comet’s surface. From
the data, the Alice team discovered the comet is unusually dark -- darker than
charcoal-black -- when viewed in ultraviolet wavelengths. Alice also detected
both hydrogen and oxygen in the comet’s coma, or atmosphere.
Rosetta scientists also discovered the comet’s surface so far shows no large
water-ice patches. The team expected to see ice patches on the comet’s surface
because it is too far away for the sun’s warmth to turn its water into
vapor.
"We’re a bit surprised at just how unreflective the comet’s surface is and
how little evidence of exposed water-ice it shows," said Alan Stern, Alice
principal investigator at the Southwest Research Institute in Boulder,
Colorado.
Alice is probing the origin, composition and workings of comet
67P/Churyumov-Gerasimenko, to gather sensitive, high-resolution insights that
cannot be obtained by either ground-based or Earth-orbiting observation. It has
more than 1,000 times the data-gathering capability of instruments flown a
generation ago, yet it weighs less than nine pounds (four kilograms) and draws
just four watts of power. The instrument is one of two full instruments on board
Rosetta that are funded by NASA. The agency also provided portions of two other
instrument suites.
Other U.S. contributions aboard the spacecraft are the Microwave Instrument
for Rosetta Orbiter (MIRO), the Ion and Electron Sensor (IES), part of the
Rosetta Plasma Consortium Suite, and the Double Focusing Mass Spectrometer
(DFMS) electronics package for the Rosetta Orbiter Spectrometer for Ion Neutral
Analysis (ROSINA). They are part of a suite of 11 total science instruments
aboard Rosetta.
MIRO is designed to provide data on how gas and dust leave the surface of the
nucleus to form the coma and tail that gives comets their intrinsic beauty. IES
is part of a suite of five instruments to analyze the plasma environment of the
comet, particularly the coma.
To obtain the orbital velocity necessary to reach its comet target, the
Rosetta spacecraft took advantage of four gravity assists (three from Earth, one
from Mars) and an almost three-year period of deep space hibernation, waking up
in January 2014 in time to prepare for its rendezvous with
67P/Churyumov-Gerasimenko.
Rosetta also carries a lander, Philae, which will drop to the comet’s surface
in November 2014.
The comet observations will help scientists learn more about the origin and
evolution of our solar system and the role comets may have played in providing
Earth with water, and perhaps even life.
Rosetta is an ESA mission with contributions from its member states and NASA.
Rosetta's Philae lander is provided by a consortium led by the German Aerospace
Center in Cologne; Max Planck Institute for Solar System Research in Göttingen;
French National Space Agency in Paris; and the Italian Space Agency in
Rome.
NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the
U.S. contribution to the Rosetta mission for the agency’s Science Mission
Directorate in Washington. JPL also built the MIRO instrument and hosts its
principal investigator, Samuel Gulkis. The Southwest Research Institute, located
in San Antonio and Boulder, developed Rosetta’s IES and Alice instruments and
hosts their principal investigators, James Burch (IES) and Alan Stern
(Alice).
For more information on the U.S. instruments aboard Rosetta, visit:
More information about Rosetta is available at:
NASA
Guillermo Gonzalo Sánchez Achutegui
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