  The concept of a stare-mode astrometric space mission is introduced. The
traditionally accepted mode of operation for a mapping astrometric space
mission is that of a continuously scanning satellite, like the successful
Hipparcos and planned Gaia missions. With the advent of astrometry missions
mapping out stars to 20th magnitude, the stare-mode becomes competitive. A
stare-mode of operation has several advantages over a scanning missions if
absolute parallax and throughput issues can be successfully addressed.
Requirements for a stare-mode operation are outlined. The mission precision for
a stare-mode astrometric mission is derived as a function of instrumental
parameters with examples given. The stare-mode concept has been accepted as
baseline for the NASA roadmap study of the Origins Billions Star Survey (OBSS)
mission and the Milli-arcsecond Pathfinder Survey (MAPS) micro-satellite
proposed project.
