  Future dark energy space missions such as JDEM and EUCLID are being designed
to survey the galaxy population to trace the geometry of the universe and the
growth of structure, which both depend on the cosmological model. To reach the
goal of high precision cosmology they need to evaluate the capabilities of
different instrument designs based on realistic mock catalog. The aim of this
paper is to construct realistic and flexible mock catalogs based on our
knowledge of galaxy population from current deep surveys. We explore two
categories of mock catalog : (i) based on luminosity functions fit of
observations (GOODS, UDF,COSMOS,VVDS) using the Le Phare software (ii) based on
the observed COSMOS galaxy distribution which benefits from all the properties
of the data-rich COSMOS survey. For these two catalogs, we have produced
simulated number counts in several bands, color diagrams and redshift
distribution for validation against real observational data. We also derive
some basic requirements to help designing future Dark Energy mission in terms
of number of galaxies available for the weak-lensing analysis as a function of
the PSF size and depth of the survey. We also compute the spectroscopic success
rate for future spectroscopic redshift surveys (i) aiming at measuring BAO in
the case of the wide field spectroscopic redshift survey, and (ii) for the
photometric redshift calibration survey which is required to achieve weak
lensing tomography with great accuracy. They will be publicly accessible at
http://lamwws.oamp.fr/cosmowiki/RealisticSpectroPhotCat, or by request to the
first author of this paper.
