GeminiFocus 2014 Year in Review | Page 43

ing Tool has GPI skeletons implemented. These skeletons allow a one-click approach to have fully-defined observations. A total of 12 GPI science programs now exist; requiring 72 hours of telescope time. For many involved in the Gemini Planet Imager (GPI), recent efforts have concentrated on preparation for the SPIE 2014 conference in Montréal in which GPI had a huge presence. The extended GPI team delivered almost 20 presentations on various aspects of the instrument. See all Gemini-related SPIE abstracts here. See updates in October 2014 (p. 37) and January 2015 (p. 35). Gemini North Dome Repairs In late May, the discovery that the second dome shutter drive unit had failed at Gemini North prompted an unscheduled shutdown in order to make necessary repairs (Figure 11). Because this is the second of these drive units to fail at Gemini North, the repairs went relatively quickly and downtime was kept to a minimum (in the earlier instance the weather was also an issue; see article in the previous issue of GeminiFocus for details on repairs to the identical unit on the opposite side of the dome top shutter). Work is ongoing to better understand why these units both failed at Gemini North and to minimize the possibility that they will do so unexpectedly at Gemini South. April 2014 Shutter Work Completed at Gemini North In late December 2013, Gemini North joined the significant group of telescopes that have suffered major failures in their dome systems. A top shutter drive unit had a critical failure with one of its spherical bearings. These drive boxes are designed to last 50 years under normal operating conditions, so clearly it was a faulty mechanism and had to be replaced. Because this failure rendered the dome unusable, repairing the unit became a highpriority project — one that needed to be completed before science operations could recommence at Gemini North. Removing this system proved extremely challenging. The Gemini North engineering team (Figure 12) worked with external consultants to develop an entirely new set of procedures to pin the shutters in place and extract the broken drive box (which weighs more than two tons and is not amenable to in-situ repair). Bad weather hampered an already difficult situation — winds well over 100 miles per hour were encountered in January, and there was significant snowfall during the period. The team finally extracted the unit from the dome at the end of January. Work then progressed very quickly as the unit was inspected, potential Figure 12. The dome repair team, just before lifting the repaired gearbox back into position. For more details on this work, see the blog that features highlights from the shutdown (including a video illustrating the difficulties of accessing the drive unit) available here. January 2015 2014 Year in Review GeminiFocus 41