Absolute astrometry in the next 50 years

Understand

With Gaia in orbit since December 2013 it is time to look at the future of fundamental astrometry and a time frame of 50 years is needed in this matter.

• A space mission with Gaia-like astrometric performance is required, but not necessarily a Gaia-like satellite.
• It should be studied whether this can be obtained within the budget of a medium-size ESA mission.
• A dozen science issues for a Gaia successor mission in twenty years, with launch about 2033, are presented and in this context also other possibilities for absolute astrometry with milliarcsecond (mas) or sub-mas accuracies are discussed.