APEX beyond 2016: the evolution of an experiment into an efficient and productive Submillimeter Wavelength Observatory

The Atacama Pathfinder EXperiment (APEX) operates a 12m submillimeter wavelength telescope in the high Andes in Chile at 5107 m above sea level since 20061. Several steps have been taken to improve the operation efficiency of the facility in the given harsh environmental conditions2. The developments in remote control and -sensing allowed in 2017 for the transition to a remote science operations scheme, observing 24/7 from the basecamp control center in San Pedro de Atacama. Also engineering and maintenance is in the transition phase to a similar scheme to minimize presence and activities at the very high site. Instrument control servers allowing remote operation even of heterodyne THz instrumentation, with no compromise on instrument performance, had been developed and proven to reliably work3. The transition to full remote science operations required major hardware upgrades on the antenna drive system and a failsafe remote-control system to ensure the safety of the antenna, the Sun Avoidance System (SAS). We report on the layout, the implementation and on the experience of the first year of this new operations model started in April 2017. The engineering tasks also are in a transition phase to a scheme that minimizes the presence at the antenna. Daily engineering work at the high site for preventive and corrective maintenance can be reduced when all critical hardware systems are integrated in a remote monitoring and control system. We have started with this in 2015 and have stepwise introduced this new scheme. This required the introduction of redundancies of systems as well as the extension of sensing points and remote-control interfaces, throughout all levels in the project breakdown structure of the telescope and its auxiliary systems. We present examples of theses implemented systems and discuss the concept of redundancies. The APEX observatory is the smallest ESO site in Chile, incorporated as a department of LPO, the ESO La Silla – Paranal Observatory, within the directorate of Operations (DoO). The work presented will attempt an outline of approaches that can be applied to telescopes exposed to similar environmental conditions as well as to larger and distributed operations such as envisaged for the Paranal Observatory extended by the ELT on Cerro Armazones.