Gaia Mission by jojo

Satellite

Gaia will be launched on a Soyuz-FG rocket and will fly to the Lagrange point L2 located approximately 1.5 million kilometers from Earth. The L2 point will provide the spacecraft with a very stable thermal environment. There it will describe a Lissajous orbit which will avoid eclipses of the Sun by the Earth, which would otherwise limit the amount of solar energy the satellite can retrieve through its solar panels and also disturb the thermal equilibrium.

Measurement principles

Similarly to its predecessor Hipparcos, Gaia consists of two telescopes providing two observing directions with a fixed, wide angle between them. The spacecraft rotates continuously around an axis perpendicular to the two telescopes line of sight (LOS). The spin axis in turn has a slight precession across the sky, while maintaining the same angle to the Sun. By precisely measuring the relative positions of objects from both observing directions, a rigid system of reference is obtained.

Each celestial object will be observed on average about 70 times during the mission, which is expected to last 5 years. These measurements will help determine the astrometric parameters of stars: 2 corresponding to the angular position of a given star on the sky, 2 for the derivatives of the star's position over time (motion) and lastly, the stars parallax.

One measurement that is however lacking by the above telescopes is the radial velocity of the star. This is obtained separately using the Doppler Effect by a spectrometer that is also onboard Gaia.

Features

The Gaia payload consists of

a 1.4 x 0.5 square metre mirror for each telescope

A 1.0 x 0.5 m focal plane array on which light from both telescopes are projected. This in turn consists of 106 CCDs of 4500 x 1966 pixels. Some of these CCDs are equipped with filters.

Gaia contains 3 separate instruments:

The astrometry instrument (ASTRO), which is dedicated to measuring the angular position of the stars of magnitude 5.7 to 20.

The photometric instrument, which allows the acquisition of spectra of stars over the 320-1000nm spectral band, over the same magnitude 5.7-20.

The high-resolution spectrometer to measure the radial velocity of the stars by acquiring high-resolution spectra in the spectral band 847-874nm (field lines of calcium ion) for objects up to magnitude 17 ,

The telemetric link with the satellite is about 1 Mbit/s on average, while the total content of the focal plane represents several Gbit/s. Therefore only a few dozen pixels around each object can be downlinked. This means that detection and monitoring of objects on board mandatory, with such processing particularly complex when scanning dense stellar fields.

Mission

The mission was adopted by ESA as cornerstone mission number 6 on 13 October 2000 and the B2 phase of the project was authorized on February 9, 2006, with EADS Astrium taking responsibility for the hardware. The launch is planned for Spring 2012. The total cost of the mission is around 450 million euros, including the manufacture, launch and ground operations.

The overall data volume that will be retrieved from the spacecraft during the 5-year mission assuming a nominal compressed data rate of 1 Mbit/s is approximately 60 TB, amounting to about 200 TB of usable uncompressed data on the ground. The responsibility of the data processing, not funded by ESA, has been entrusted to the a European consortium (the Data Processing and Analysis Consortium, abridged in DPAC) which has successfully been selected after from its proposal to the ESA Announcement of Opportunity released in November 2006.

The DPAC is a collaboration of about 400 astronomers and IT engineers from 20 European countries, including a significant participation of an ESA group based at the the European Space Astronomy Centre (ESAC), one of the ESA centre in Europe located near Madrid. The funding is provided by the participating countries and has been secured until the production of the Gaia final Catalogue scheduled for 2020.

Objectives

The Gaia space mission has the following objectives:

To determine the intrinsic luminosity of a star requires knowledge of its distance. One of the only ways to achieve without physical assumptions is through the star's parallax. Ground-based observations would not measure such parallaxes with sufficient precision due to the effects of the atmosphere and instrumental biases.

Observations of the faintest objects will provide a more complete view of the stellar luminosity function. We must observe all the objects up to a certain magnitude in order to have unbiased samples.

You need a large amount of objects to examine the more rapid stages of stellar evolution. Observing a large number of objects in the galaxy is also important in order to understand the dynamics of our galaxy. Note that a billion stars represents only 1% of the content of our galaxy.

Measuring the astrometric and kinematic properties of star is necessary in order to understand the various stellar populations, especially the most distant.

Gaia is expected to:

Measure the astrometric properties of over a billion stars down to a magnitude of V = 20

Determine the positions of stars at a magnitude of V=10 down to a precision of 7 millionths of an arcsecond (as) (this is equivalent to measuring the diameter of a hair from 1000km away); between 12 and 25 as down to V = 15, and between 100 and 300 as to V = 20, depending on the color of the star

Measure the tangential speed of 40 million stars to a precision of better than 0.5km / s

References

^ ESA Portal - Mapping the Galaxy, and watching our backyard

Further reading

Thorsten Dambeck in Sky and Telescope, Gaia's Mission to the Milky Way, March 2008, p.36 - 39

External links

Wikimedia Commons has media related to: Gaia (satellite)

ESA Gaia mission

Gaia in Depth

Gaia page at ESA Spacecraft Operations

Gaia pages for the scientific community

Gaia Study Report Summary of the scientific goals of the mission, March 2000

Origins Billion Star Survey (OBSS) A similar project proposal as collaboration between NASA and U.S. Naval Observatory.

vde

Space observatories

Current

AGILE Suzaku COROT Chandra X-ray Observatory Fermi Gamma-ray Space Telescope GALEX Herschel Space Observatory HETE-2 Hubble Space Telescope INTEGRAL Kepler LEGRI MOST PAMELA Planck Solar Dynamics Observatory Rossi X-ray Timing Explorer Spitzer Space Telescope SWAS Swift Gamma-Ray Burst Mission TRACE Wide Field Infrared Explorer Wide-field Infrared Survey Explorer WMAP XMM-Newton

Planned

TAUVEX (2010) RadioAstron (2010) Astrosat (2010) NuSTAR (2011) Spectrum-X-Gamma (2012) Gaia mission (2012) Hard X-ray Modulation Telescope (HXMT) (2012) Transiting Exoplanet Survey Satellite (TESS) (2012) New Worlds Mission (2013) ASTRO-G (2013) James Webb Space Telescope (JWST) (2014) Darwin (2016) Space Interferometry Mission (2016) Laser Interferometer Space Antenna (LISA) (2020)

Proposed

Constellation-X Observatory XEUS Dark Energy Space Telescope Terrestrial Planet Finder Fresnel Imager SPICA THEIA PLATO ATLAST International X-ray Observatory

Completed

ABRAXIS AKARI Advanced Satellite for Cosmology and Astrophysics ALEXIS Aryabhata Astro 2 Astron Astronomical Netherlands Satellite BeppoSAX Broad Band X-ray Telescope Compton Gamma Ray Observatory Copernicus Observatory Cos-B Cosmic Background Explorer Einstein Observatory EXOSAT Extreme Ultraviolet Explorer Far Ultraviolet Spectroscopic Explorer Ginga Granat Hakucho HALCA HETE HEAO-1 HEAO-3 Hipparcos Infrared Space Observatory International Ultraviolet Explorer IRAS Midcourse Space Experiment Odin OAO-2 RELIKT-1 ROSAT SAS-B Tenma Uhuru Yohkoh

Canceled

Eddington mission

See also

Space observatory List of space telescopes Great Observatories program

Space observatories category

vde

European Space Agency

Spaceports

Guiana Space Centre Esrange

Programmes

Aurora Programme Living Planet (Earth Observation, Earth Watch) Programme Orfeo Programme Technology Transfer Programme

Related

EUMETSAT European Space Camp Arianespace Planetary Science Archive GEWEX

Projects

Cancelled

Eddington mission EADS Phoenix Hermes

Failed

CryoSat

Current

Active

Artemis ATV Cluster Columbus Corot Envisat ERS-2 GIOVE-A GIOVE-B Galileo positioning system GOCE Herschel Space Observatory Hubble Space Telescope Integral Mars Express MetOp-A Planck Proba-2 Rosetta SOHO SMOS XMM-Newton Venus Express

Queued

ADM-Aeolus BepiColombo CryoSat-2 Don Quijote ExoMars Galileo positioning system Gaia KEO James Webb Space Telescope LISA Pathfinder

Future

Advanced Re-entry Vehicle Cosmic Vision XEUS Darwin Mission FLPP IXV Mars sample return mission Proba-3 Solar Orbiter Laplace TandEM

Past

Cos-B Chandrayaan-1 Double Star ERS-1 EURECA Giotto mission Hipparcos Huygens probe ISO IUE SMART 1 Ulysses YES2

Portal

vde

This spacecraft or satellite related article is a stub. You can help Wikipedia by expanding it.

vde

vde

Categories: Space telescopes | European Space Agency probes | Proposed spacecraft | 2011 in spaceflight | Astronomical observatory stubs | Spacecraft stubs | Space program stubs

I am an expert from China Crafts Suppliers, usually analyzes all kind of industries situation, such as print drapery fabric , fleece fabric panels.

Article Source: http://www.earticlesonline.com/Article/Gaia-Mission/839181

Kinematic Mirror Videos

Free Keyword Spy Tool - See Keyword Directly From Google in Real-Time

Tired of searching for those high paying keywords?Any Internet marketer will tell you that using the right keywords will flood your site with traffic.Just think of the time you would save by knowing exactly what your competitors were bidding on and how much they were paying?Imagine being able to see their maximum bid for each keyword in their Adwords account?  Armed with this information you could literally dominate any niche you choose!

Well...your wait is over.  Brad Callen has created the next generation of keyword tools, PPC Web Spy is the ultimate in keyword research tools available today.  You can use it to literally steal each and every keyword your competitors are bidding on in Adwords.PPC Web Spy will not only show you the number of clicks they are getting per day but also show you the maximum price they are bidding for each one.The thing I like most about the software is that you never have to leave the Google search page to get all of this information.

PPC Web Spy is a Firefox add-on that lets you click a button under each Adwords ad to display all the keyword data for that particular marketer.The cost of development for the software alone was over $127,000!I can't believe he is doing this but the cost for you to get this product today is....are you ready for this?  NOTHING!That was not a misprint...Brad is actually giving this software away!

Don't waste another second.  You have got to check this out and see it in action with your own eyes.This tool will soon be outlawed by Google.  You will get more keywords than you've ever imagined and they will be precisely targeted for your exact niche that you are searching for.

See Screenshots and Download PPC Web Spy for FREE  Right Now

You will not be disappointed.

How To Make Schlieren Pictures.wmv