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 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 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 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 cometary 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.
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