Gaia will detect all Jupiters within couple of hundred of light years (IIRC) which have orbital periods less than ten years. Gaia mission lasts for five years and it can detect planets that have made at least half of their orbital revolutions. Astrometric detection allows the measurement of planet's absolute mass.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
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Take multiple measurements, say at three points in Earth's orbit for two years. Three points should solve tranverse motion and doubling allows for transient lensing effects, as well as a measurement quality assessment.

Wow that's awesome.

Better for DM 61 366-esp. if a mistake was made and the earlier measurement proves correct.

Young Graduate Trainee position
http://www.rssd.esa.int/index.php?pr...AIA&page=index

Its billion-pixel camera will be in fact composed of 170 separate cameras, tiled together in a mosaic to register every object that passes through the field of view. Each individual camera or 'charge-coupled device' (CCD) will have a resolution of almost nine million pixels. Gaia will take images for five years.
http://radio.weblogs.com/0105910/2004/09/13.html

Although an astrometric spacecraft sent out of the Solar System will get a much larger parallax than a near-Earth astrometric spacecraft ever will, it will also have the serious problem of sending its data back to Earth, simply because of its large distance.

GAIA will be at 0.01 AU or 1.5 million km, while to significantly improve on the Earth's orbit requires a distance of at least 10 AU, or 1.5 billion km. If one assumes that both satellites transmit their data with the same transmitter power, then the outer-Solar-System one will have a received intensity a millionth that of the near-Earth one. This means that the OSS one must transmit at a millionth of the bitrate of the NE one in order to have the same signal/noise margins. So the OSS spacecraft is likely to make GAIA-quality measurements of only a thousand stars, or else lower-quality measurements of many more stars.

That problem could be resolved by using a more powerful transmitter, but beyond a certain point, that will require powering the transmitter with a nuclear reactor.

That said, GAIA will do lots of Nice Things. What Hipparcos did for the Hyades, GAIA will do for more distant star clusters, and also for Cepheid variables -- find distances directly, without going through such intermediate steps as moving-cluster or main-sequence fitting. For more, see this diagram of how distance-measurement techniques overlap (with this parent page).

GAIA will also record the deflection of starlight by the Sun's gravity as it travels into the Solar System; it will provide a test of a prediction of General Relativity with an accuracy of 10^-3, comparable to that of VLBI position measurements.

For more on this sort of test, see The Confrontation between General Relativity and Experiment (rather technical!).

... success of Venus Express can be attributed to Andenes. Similarly, the present much reduced demand on the programme foreseen originally for GAIA is another solid benefit in circumstances where the budget has more than 20% less spending power than when GAIA was selected
http://www.spaceref.com/news/viewsr.html?pid=19140
...The innovations referred to in the previous paragraph involve and even empower the SPC in critical managerial choices early on (in phase B) and allow applying sanctions with much less risk of the wasted expenditure that is inevitable if such actions were to be taken during phase C/D. At present, the SPC is due to make critical decisions on proceeding with GAIA and BepiColombo. Both are now predicted to exceed the Andenes targets. Moreover, at the time of writing, a formal agreement for the BepiColombo payload is yet to be agreed. It is expected that the SPC will make its critical decisions in February 2006.

Launches in December 2011

2006-02-09 Unanimous approval for Gaia from the SPC
ESA's Science Programme Committee today unanimously approved the Gaia mission and the requested Cost at Completion. The mission now proceeds to Phase B2 with a kick-off meeting with the prime contractor EADS Astrium next week.
http://www.rssd.esa.int/index.php?pr...AIA&page=index
2006-01-26 Postdoc position on eclipsing binaries at ULB
The Institute of Astronomy and Astrophysics at the Université Libre de Bruxelles is offering a postdoctoral position to participate in the development of algorithms and software - related to eclipsing binaries (and potentially transiting planets) - for the Gaia data processing. The position is funded for two years with the possibility of extensions until the end of the Gaia data processing phase (around 2019). A starting date of 1 May 2006 is envisaged, but is flexible. Evaluation of candidates will begin 1 March 2006; later applications will be considered until a suitable candidate is identified. Further details are available online.

a billion stars for 5 years?

Thats a star every 0.15 seconds!

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P.S. This is what part of the alphabet would look like if Q and R were eliminated.

-- Mitch Hedberg

Sweet!

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http://www.ryanmercer.com

more on the mission here

http://staff.imsa.edu/science/astro/...ry/rung2a.html
http://www.strw.leidenuniv.nl/nova/i...ents/Gaia.html

Thread moved from Astronomy to Space Exploration

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Everything I need to know I learned through Googling.

very good space telescope and an important astrometry mission - 3d map of billions of stars, it will give us distances, and annual proper motions of stars, find new asteroids and discover extra solar worlds.

2006-03-20 Change in Project Scientist
After the successful selection of the industrial contractor for Phase B2/C/D of Gaia, and confirmation of the implementation and launch schedule by the Science Programme Committee, Michael Perryman stands down as ESA's project scientist for Gaia. Taking his place is Dr Fred Jansen, formerly project scientist for XMM-Newton and currently mission manager for XMM-Newton and Mars Express. He will transfer his responsibilities as XMM-Newton mission manager while maintaining his role on Mars Express. The change in project scientist is effective as of 20 March 2006.

images and media
http://www.rssd.esa.int/index.php?pr...ge=IG_overview
http://www.rssd.esa.int/index.php?pr...imedia_gallery

Thanks MT. Gaia is a very important upcoming mission, and I'd mised the news about the personnel change.

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Gaia really does sound like a very, very good mission. It's one of them low-cost, low-risk but scientifically wealthy robotic missions at which ESA has been so good.

http://www.wikipedia.com/wiki/Gaia_probe
From the Wikipedia article on Gaia:

Gaia will compile a catalogue of approximately one billion stars to magnitude 20. Its objectives comprise (a) astrometric (or positional) measurements, determining the positions, distances, and annual proper motions of stars with an accuracy of about 20 micro-arcsec at 15 mag, and 200 micro-arcsec at 20 mag; (b) photometric measurements, providing multi-colour multi-epoch observations of each detected object; and (c) radial velocity measurements. Gaia will create an extremely precise three-dimensional map of stars throughout our Galaxy and beyond, and map their motions which encode the origin and subsequent evolution of the Galaxy. The photometric measurements will provide the detailed physical properties of each star observed, characterising their luminosity, temperature, gravity, and elemental composition. This massive stellar census will provide the basic observational data to tackle a wide range of important problems related to the origin, structure, and evolutionary history of our Galaxy. Large numbers of quasars, extra-solar planets, and solar system bodies will be measured at the same time.

This really does sound like an achivement. The first stellar census? We could very well end up finding hundreds of not thousands of earthlike planets as a result of this mission. I really hope this programme continues to fruition and is at successful as possible.

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If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.
-- Bertrand Russell (1872-1970)

I wouldn't call it low cost... but it will be worth it.

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Forming opinions as we speak

$260m USD and made mostly from spare parts is pretty cheap in my book when compared to even the cheapest of manned missions. And much better scientific value pound-for-pund than, say, the ISS - at least in my opinion.

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If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.
-- Bertrand Russell (1872-1970)

I had the impression that the total mission cost was about a billion euros. This is a big difference, now I have to look it up. More later.

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Forming opinions as we speak

Adjusted for time the whole mission works out at about 450-600 Million Euro, still not much ( just one euro per person in each ESA nation )