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The Rosetta Mission (Part 1): History and Mission Objectives

written by: Anurag Ghosh•edited by: RC Davison•updated: 5/23/2011

With the successful Giotto mission to Halley’s Comet it was necessary for follow-on missions, therefore, the Rosetta mission was intended to study more about comets and unlock the secrets of the solar system. This article explains the history of the Rosetta spacecraft mission.

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    Rosetta Space Mission: Information and Launch Date

    The European Space Agency’s (ESA’s) successful Giotto mission to Halley’s Comet placed them at the forefront in exploring comets. Among a number of international space probes sent to explore the Halley’s cometary system, the Giotto mission was the most successful. This successful mission opened the doors for more cometary missions and motivated ESA to launch another space probe for a more in-depth analysis of comets which would help them to understand the solar system better. The space probe was named ‘Rosetta’ after the ‘Rosetta stone’ which helped in unlocking the meaning of Egyptian hieroglyphics.

    The Rosetta spacecraft is built to help scientists decipher the meaning and role of comets in determining the history of the solar system. The Rosetta space mission is intended to study the nucleus of the comet, its exact composition, whether the comet disappears after dying, the building blocks of the comet and many other unanswered questions.

    When was Rosetta launched?

    The ESA launched the Rosetta spacecraft on 2 March 2004 at 7:17 UT from Kourou, French Guiana. The robotic spacecraft mission consists of a large orbiter and a Philae Lander carrying a set of instruments used for scientific experiments. The objective of the Rosetta mission is to drop a probe on the surface of Comet 67 P/ Churyumov-Gerasimenko, and study it from orbit. The principle goals are to analyze the connection between cometary and interstellar material and the origin of comets. It will approach Comet Churyumov-Gerasimenko in May 2014 after deep-space hibernation during May 2011-january 2014. The space probe will land on the comet’s surface in November 2014 and lead the comet around the sun. This will continue till December 2015.

    Rosetta was launched in March 2004 after two unsuccessful launch attempts; the first launch attempt was scheduled on January 12 2003 to approach a different comet 46P/Wirtanen, however, a technical failure of the planned launch vehicle Ariane 5 on December 11 2002 resulted in postponing the mission. The second launch attempt was scheduled on February 26, 2004 with a new plan to target the comet Churyumove-Gerasimenko, but it was necessary to modify the landing gear due to its larger mass and the resulting increased impact velocity.

    Rosetta spacecraft 

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    The Rosetta Space Mission Instruments for Scientific Experiments

    The Orbiter has eleven scientific instruments and the Philae Lander has nine scientific instruments.

    The scientific instruments of the Rosetta orbiter are: (in alphabetical order)>

    1. Comet Nucleus Sounding (CONSERT): CONSERT is the best instrument used for probing the interior of the comet. This instrument studies radio waves that are scattered and reflected by the nucleus of the comet.

    2. Cometary Secondary Ion Mass Analyzer (COSIMA): The Cometary Secondary Ion Mass Analyzer will scrutinize the composition of dust grains emitted by the comet to ascertain whether they are organic or inorganic.

    3. Grain Impact Analyzer and Dust Accumulator (GIADA): This instrument will analyze and measure the momentum, mass, number and velocity distribution of dust grains coming from the nucleus of a comet.

    4. Micro-Imaging Analysis System (MIDAS): MIDAS provides information on the population, volume, size and shape of particles by studying the dust environment around comets and asteroids.

    5. Microwave Instrument for the Rosetta Orbiter (MIRO): The main objective of MIRO is to study and calculate the subsurface temperature of the comet’s nucleus and the properties of major gases.

    6. Rosetta Orbiter Imaging System (OSIRIS): OSIRIS or Optical Spectroscopic and Infrared Remote Imaging System will capture high-resolution images of the comet’s nucleus and the asteroids with a wide-angled and narrow-angled camera. It is the finest imaging system that will also help to identify the best landing site of Comet 67P/ Churyumov-Gerasimenko.

    7. Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA): This scientific instrument contains two sensors which will help in ascertaining the composition of the comet’s ionosphere and atmosphere, as well as the velocities of electrified gas particles.

    8. Rosetta Plasma Consortium (RPC): RPC has five sensors which will monitor any activity of the comet, study its interactivity with the solar wind, measure the properties of the comet’s nucleus and analyze the structure of the inner coma.

    9. Radio Science Investigation (RSI): This instrument will study the solar corona during the period when the Rosetta spacecraft passes behind the sun (as seen from Earth). The RSI will also measure the density, gravity and mass of the comet’s nucleus. The RSI will define the comet’s orbit as well as analyze the comet’s inner coma.

    10. Ultraviolet Imaging Spectrometer (ALICE): The Ultraviolet Imaging Spectrometer will detect the abundance of noble gases in the comet’s core by using a range of caesium iodide and potassium bromide photo cathodes. It will also provide crucial information on the nucleus’ surface composition and measure the comet’s production rates of carbon monoxide/dioxide and h0.

    11. Visible and Infrared Mapping Spectrometer (VIRTIS): VIRTIS will classify the comet gases, and differentiate the physical conditions of the comet’s coma. It will also analyze the nucleus’ surface temperature.

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    The Scientific Instruments of the 100-kilogram Rosetta Lander

    1. Alpha Proton X-ray Spectrometer (APXS): This instrument detects X-rays and alpha particles which provide data on the fundamental composition of the comet’s surface. The APXS will be lowered within 40 mm of the ground.

    2. Rosetta Lander Imaging System (ÇIVA / ROLIS): The Lander imaging system of the Rosetta spacecraft has six micro-cameras that have similar characteristics. The identical cameras will capture panoramic images of the comet’s surface. The CIVA has a spectrometer which studies the texture, composition and the reflectivity of samples collected from the surface of the comet.

    3. Comet Nucleus Sounding (CONSERT): CONSERT analyzes the internal structure of the nucleus.

    4. Cometary Sampling and Composition experiment (COSAC): this instrument will perform EGA or evolved gas analysis. COSAC will analyze the elemental and molecular composition of gases and detects and analyzes the complex organic molecules from them.

    5. Evolved Gas Analyzer (MODULUS PTOLEMY): MODULUS PTOLEMY is the second gas analyzer which will acquire precise amounts of isotopic ratios of light elements.

    6. Multi-Purpose Sensor for Surface and Subsurface Science (MUPUS): It probes the surface of the comet and derives mechanical and thermal characteristics of the comet’s surface. It uses sensors on the Landers anchor to probe the surface.

    7. RoLand Magnetometer and Plasma Monitor (ROMAP): ROMAP will combine a plasma monitor and a magnetometer. It will study the interaction between comet and solar wind.

    8. Sample and Distribution Device (SD2): SD2 is a sample and distribution device collects samples and delivers them to for microscopic inspection. The SD2 will drill more than 200 mm into comet’s surface and collect samples.

    9. Surface Electric Sounding and Acoustic Monitoring Experimen (SESAME): This scientific instrument consists of three instruments viz. the Dust Impact Monitor, the Permittivity Probe and the Cometary Acoustic Sounding Experiment. The main goal of this instrument is to analyze the comet nucleus’ surface. The results will be of utmost importance to scientists as it will help them to develop a model to understand the formation of the comet and the solar system.

    Rosetta Flyby’s:

    The Rosetta spacecraft brushed the Earth’s orbit on the 4th of March, 2005 and again on the 13th of November, 2007. The Mars fly-by occurred on the 25th of February 2007, but the most important fly-by occurred on the 5th of September, 2008 when it passed close to asteroid Stein with the intention of taking accurate measurements of the asteroid’s size and also to take images and spectra for drawing conclusions about its composition. The second article in this series gives more in-depth information about the Steins Flyby.

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    Image reference:

The International Rosetta Mission History and Current Events

The Rosetta space probe was launched by the European Space Agency with the objective of rendezvousing with a comet and placing a lander on it in 2014. Recently it passed by a small asteroid, Steins, and provided some very useful data
  1. The Rosetta Mission (Part 1): History and Mission Objectives
  2. The Rosetta Mission (Part 2): Steins Flyby