Great news from the Hubble Space Telescope: Our observing proposal “Andromeda and the Seven Dwarfs: M31 Mass, Satellite Orbits, and the Nature of the Satellite Plane”, was awarded observing time. The proposal is lead by Tony Sohn and is part of the HSTPROMO collaboration. For a whopping 48 orbits, the Space Telescope will observe our targets (green stars in my figure on the right). These measurements will reveal the proper motions (i.e. motions on the sky) of seven M31 satellite galaxies. This will be the first time that we will be able to study the full 3D motions (and thus 6D phase-space coordinates) of a sample of satellite galaxies outside of our Milky Way. And it will be a first step in determining how dynamically stable (or rotationally supported) the plane of satellite galaxies around Andromeda is.