Context : The ESA Gaia mission , to be launched during 2013 , will observe billions of objects , among which many galaxies , during its 5 yr scanning of the sky .
This will provide a large space-based dataset with unprecedented spatial resolution .

Aims : Because of its natural Galactic and astrometric priority , Gaia ’ s observational strategy was optimized for point sources .
Nonetheless , it is expected that \sim 10 ^ { 6 } sources will be extragalactic , and a large portion of them will be angularly small galaxies .
Although the mission was designed for point sources , an analysis of the raw data will allow the recovery of morphology of those objects at a \sim 0.2 " level .
This may constitute a unique all-sky survey of such galaxies .
We describe the conceptual design of the method adopted for the morphological analysis of these objects as well as first results obtained from data simulations of low-resolution highly binned data .

Methods : First , the raw Gaia 1D observations are used to reconstruct a 2D image of the object – this image is known to contain artifacts and reconstruction signatures .
Then , parameters characteristic of the reconstructed image are measured , and used for a purely morphological classification .
Finally , based on the classification , a light profile is selected ( pure-disk , disk+bulge , pure bulge , point source+disk , etc . )
and fitted to all Gaia 1D observations simultaneously in a global process using forward modeling .

Results : Using simulations of Gaia observations from official Gaia Data Processing and Analysis Consortium tools , we were able to obtain the preliminary classification of the simulated objects at the \sim 83 \% level for two classes ( ellipticals , spirals/irregulars ) or at the \sim 79 \% , \sim 56 \% , and \sim 74 \% levels for three classes ( E , S and I ) .
The morphological parameters of simulated object light profiles are recovered with errors at the following levels : -9 \pm 36 \% for the bulge radius , 11 \pm 53 \% for the bulge intensity , 1 \pm 4 \% for the disk radius , and -1 \pm± 7 \% for the disk intensity .
From these results , we conclude that it is possible to push the limits of the Gaia space mission by analysing galaxy morphology .

Conclusions :