Artist’s impression of the Rosetta orbiter at comet
67P/Churyumov–Gerasimenko. (Not to scale.)
Image Credit: NASA/ESA/JPL
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Three NASA science instruments are being prepared for check-out operations
aboard the European Space Agency's Rosetta spacecraft, which is set to become
the first to orbit a comet and land a probe on its nucleus in November.
Rosetta was reactivated Jan. 20 after a record 957 days in hibernation. U.S.
mission managers are scheduled to activate their instruments on the spacecraft
in early March and begin science operations with them in August. The instruments
are an ultraviolet imaging spectrograph, a microwave thermometer and a plasma
analyzer.
"U.S. scientists are delighted the Rosetta mission gives us a chance to
examine a comet in a way we've never seen one before -- in orbit around it and
as it kicks up in activity," said Claudia Alexander, Rosetta's U.S. project
scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "The
NASA suite of instruments will provide puzzle pieces the Rosetta science team
as a whole will put together with the other pieces to paint a portrait of how a
comet works and what it's made of."
Rosetta’s objective is to observe the comet 67P/Churyumov-Gerasimenko up
close. By examining the full composition of the comet's nucleus, and the ways in
which a comet changes, Rosetta will help scientists learn more about the origin
and evolution of our solar system and the role comets may have played in seeding
Earth with water, and perhaps even life.
The ultraviolet imaging spectrograph, called Alice, will analyze gases in the
tail of the comet, as well as the coma, the fuzzy envelope around the nucleus of
the comet. The coma develops as a comet approaches the sun. Alice also will
measure the rate at which the comet produces water, carbon monoxide and carbon
dioxide. These measurements will provide valuable information about the surface
composition of the nucleus. The instrument also will measure the amount of argon
present, an important clue about the temperature of the solar system at the time
the comet's nucleus originally formed more than 4.6 billion years ago.
The Microwave Instrument for Rosetta Orbiter will identify chemicals on or
near the comet's surface and measure the temperature of the chemicals and the
dust and ice jetting out from the comet. The instrument also will see the
gaseous activity in the tail through coma.
The Ion and Electron Sensor is part of a suite of five instruments to analyze
the plasma environment of the comet, particularly the coma. The instrument will
measure the charged particles in the sun’s outer atmosphere, or solar wind, as
they interact with the gas flowing out from the comet while Rosetta is drawing
nearer to the comet's nucleus.
NASA also provided part of the electronics package the Double Focusing Mass
Spectrometer, which is part of the Swiss-built Rosetta Orbiter Spectrometer for
Ion and Neutral Analysis (ROSINA) instrument. ROSINA will be the first
instrument with sufficient resolution to separate two molecules with
approximately the same mass: molecular nitrogen and carbon monoxide. Clear
identification of nitrogen will help scientists understand conditions at the
time the solar system was born.
U.S. science investigators are partnering on several non-U.S. instruments and
are involved in seven of the mission's 21 instrument collaborations. NASA has an
American interdisciplinary scientist involved in the research. NASA's Deep Space
Network (DSN) is supporting the European Space Agency's (ESA's) Ground Station
Network for spacecraft tracking and navigation.
Rosetta, composed of an orbiter and lander, is flying beyond the main
asteroid belt. Its lander will obtain the first images taken from the surface of
a comet, and it will provide the first analysis of a comet's composition by
drilling into the surface. Rosetta also will be the first spacecraft to witness,
at close proximity, how a comet changes as it is subjected to the increasing
intensity of the sun’s radiation.
The potential research and data from the Rosetta mission could help inform
NASA's asteroid initiative -- a mission to identify, capture and relocate an
asteroid for astronauts to explore. The initiative represents an unprecedented
technological feat that will lead to new scientific discoveries and
technological capabilities that will help protect our home planet and achieve
the goal of sending humans to an asteroid by 2025.
"Future robotic and human exploration missions to Mars, an asteroid and
beyond will be accomplished via international partnerships combining worldwide
scientific and engineering expertise," said Jim Green, director of NASA's
Planetary Science Division in Washington. “Rosetta will provide an opportunity
to study a small new world that could inform us on the best ways to approach,
orbit, and capture our target asteroid for a future human mission.”
The solar-powered spacecraft was placed into a deep sleep in June 2011, to
conserve energy during the portion of its trajectory that carried it past the
orbit of Jupiter. During Rosetta's hibernation, all instruments and subsystems
were shut off, except for the main computer including a spacecraft clock and a
few heaters. ESA mission managers are beginning to commission the spacecraft and
its instruments.
"The successful wake-up of Rosetta from its long, lonely slumber is a
testament to the teams that built and operate the spacecraft, and the
international cooperation between ESA and NASA ensured that we had some of the
world's largest deep space dishes available to relay the first signal back to
Earth," said Mark McCaughrean, senior scientific advisor in ESA's Directorate of
Science and Robotic Exploration. "There is still a lot of work ahead of us
before the exciting comet rendezvous, escort, and landing phase, but it's great
to be back online."
ESA member states and NASA contributed to the Rosetta mission. Airbus Defense
and Space built the Rosetta spacecraft. JPL manages the US contribution of the
Rosetta mission for NASA's Science Mission Directorate in Washington. JPL also
built the Microwave Instrument for the Rosetta Orbiter and hosts its principal
investigator, Samuel Gulkis. The Southwest Research Institute in San Antonio
developed the Rosetta orbiter's Ion and Electron Sensor (IES) and hosts its
principal investigator, James Burch. The Southwest Research Institute in
Boulder, Colo., developed the Alice instrument and hosts its principal
investigator, Alan Stern.
An audio replay of a media teleconference held Friday with NASA and ESA
officials discussing the mission is available until Jan. 31. The call in number
is 800-839-2235.
For information on the U.S. instruments, visit:
More information about Rosetta is available online at:
For more information on the DSN, visit:
For more information on NASA's asteroid initiative, visit:
Guillermo Gonzalo Sánchez Achutegui
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