The goal of the division is to address the scientific issues that were developed at the 2009 IAU General Assembly in Rio de Janeiro. These are:

• • Astronomical constants

• —Gaussian gravitational constant, Astronomical Unit, GMSun, geodesic precession-nutation

• • Astronomical software

• • Solar System Ephemerides

• —Pulsar research

• —Comparison of dynamical reference frames

• • Future Optical Reference Frame

• • Future Radio Reference Frame

• • Exoplanets

• —Detection

• —Dynamics

• • Predictions of Earth orientation

• • Units of measurements for astronomical quantities in relativistic context

• • Astronomical units in the relativistic framework

• • Time-dependent ecliptic in the GCRS

• • Asteroid masses

• • Review of space missions

• • Detection of gravitational waves

• • VLBI on the Moon

• • Real time electronic access to UT1-UTC

In pursuit of these goals Division I members have made significant scientific and organizational progress, and are organizing a Joint Discussion on Space-Time Reference Systems for Future Research at the 2012 IAU General Assembly. The details of Division activities and references are provided in the individual Commission and Working Group reports in this volume. A comprehensive list of references related to the work of the Division is available at the IAU Division I website at http://maia.usno.navy.mil/iaudiv1/.