  The expected accurate astrometric data from Gaia offer the opportunity and
the obligation to exploitation by a second all-sky mission. Therefore a
proposal was submitted to ESA in May 2013 for a Gaia-like mission in about
twenty years. Two new designs are here considered with NIR sensors in addition
to the visual CCDs as in Gaia. This has been suggested by several colleagues in
order to get better astrometry in obscured regions. A first design with CMOS
sensors was quickly abandoned for technical reasons. The second design with
specially developed CCDs for NIR looked more promising. But a deeper study
showed that the longer wavelength in the near infrared at two microns
deteriorates astrometry so much that only heavily obscured stars of extremely
red types as M5III would obtain a better accuracy. Thus, an option with NIR
sensors does not seem promissing.
