NASA instruments aboard Rosetta begin science as comet comes alive
Since its launch in 2004, Rosetta has been traveling through space, patiently awaiting its mission – a rendezvous and landing on a comet. Composed of an orbiter and lander, the Rosetta spacecraft was awakened from a 957 day hibernation back in January and is slated to be the first vehicle to both orbit and land on a comet.
Even though this is a European Space Agency (ESA) project, NASA has three instruments aboard the spacecraft and is in the process of turning them on, making observations, and relaying data back to Earth. Rosetta’s main objective is to rendezvous with comet 67P/Churyumov-Gerasimenko this August, observe the comet up close and in great detail before preparing to land its probe, named Philae, on the comet’s surface in November. The lander will then observe and analyze the comet’s nucleus in hopes to shed new light on how these celestial bodies evolve.
The Philae lander will be the first spacecraft to ever photograph a comet’s surface as well as provide essential compositional analysis by actually drilling into the comet’s surface. Rosetta will also be the first to witness up-close the changes a comet goes through when exposed to the Sun’s increasing radiation. All data collected will be beneficial to scientists hoping to better understand the formation and evolution of the early solar system as well as any potential role comets play in distributing water and potentially life throughout the solar system.
“We are happy to be seeing some real zeroes and ones coming down from our instruments, and cannot wait to figure out what they are telling us,” said Claudia Alexander, Rosetta’s U.S. project scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “Never before has a spacecraft pulled up and parked next to a comet. That is what Rosetta will do, and we are delighted to play a part in such a historic mission of exploration.”
Currently, Rosetta is approaching the asteroid belt (that separates in inner solar system from outer) and still has approximately 300,000 miles (500,000 kilometers) to go before it reaches comet 67P in August. Three of the 11 instruments aboard the orbiter are designed by NASA and include the Microwave Instrument for Rosetta Orbiter (MIRO), Alice (a UV spectrometer) and the Ion and Electron sensor (IES).
MIRO’s objective is to analyze how dust and gas from the comet’s nucleus come together to form the coma and the comet’s tail. It will also record surface temperatures and observe how the coma and tail evolve as the comet approaches and leaves the region around our Sun.
A comet’s coma is developed just as the comet approaches the Sun, and appears as a bright shroud of gas surrounding the nucleus. A ultraviolet spectrometer, Alice, will measure and record the gases present in the coma as well as record how much water, carbon monoxide and carbon dioxide are produced. These measurements, along with the amount of argon, will give scientists insight into the composition of the nucleus as well as important clues as to the solar system’s temperature when the nucleus formed (thought to be more than 4.6 billion years ago).
The IES is one of five instruments designed to study the plasma surrounding the comet and in particular the coma. IES will be responsible for recording the amount of charged particles in the solar wind (Sun’s outer atmosphere) and measure how they interact with gases from the comet.
In addition to these three instruments, NASA also contributed a portion of the electronics package for the Double Focusing Mass Spectrometer – part of the orbiter’s Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument. ROSINA is the first space-based instrument with the resolution needed to differentiate between molecular nitrogen and carbon monoxide. The Atacama Large Millimeter/Submillimeter Array (ALMA) at the European Southern Observatory’s (ESO) Paranal Observatory has the only ground-based instrument with this capability. Since these molecules have almost the same mass, this is a huge accomplishment and the clear identification of molecular nitrogen will enable scientists to understand conditions present in the early solar system.
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