ALMA starts the process of recovering the telescope array

Published: 01 Oct 2020
Chajnantor plateau

Dear colleagues,

The past several months have been an extraordinary period as a result of the global coronavirus pandemic. Everyone at ALMA hopes that you and your families are safe and healthy, and we extend our thoughts to those who have been directly affected by the pandemic.

For six months, almost the whole ALMA site has been shut down – power, water treatment, and running water - with only a single piece of key equipment (the hydrogen maser) still powered and checked daily as one of the tasks of the ALMA Caretaker Teams  - the teams who have ensured the safety and security of the ALMA Observatory through the shutdown.   

With the improving pandemic situation in Chile, ALMA is now scheduled to begin the long process of recovering the telescope array in the Atacama on October 1st, 2020, starting with preparation of the ALMA Operations Support Facility (OSF) at 2900 metres for the return of staff and contractors.

The road to recovery of operations, and ultimately science observations – a milestone that will not take place this year - has been carefully planned. It is difficult to predict the exact timeline since several aspects of the plan depend on prevailing conditions not under our control. However, the following describes the current plan of activities and schedule for the return of ALMA to science operations.

The ALMA Observatory has developed an extensive set of enhanced safety protocols related to managing the risk posed by the virus, covering all activities as the recovery of operations progresses. First, preparing the OSF for the return of staff and contractors, followed by moving back into the OSF and the use of the OSF facilities, before we begin the process of restarting the Array Operations Site (AOS) at 5000 metres. Without doubt, each of the phases will take time and patience, establishing and working within new safety protocols while stabilizing observatory systems that have been shut down for six months - a situation which is unprecedented in the history of the Observatory. 

The current restart plan requires about 80 days to reach the antenna power-up milestone, assuming there are no major repairs needed, or changes in the schedule due to impacts of the pandemic. The time needed to recover sufficient antennas for science observations is highly uncertain. Nevertheless, our ambition is to have antennas collecting data and verifying the observing systems after approximately 100 days - whether this is a handful, or many antennas, remains difficult to predict. This implies that January is the earliest there may be enough functional antennas and cooled receivers to attempt the first science observations.  In addition, we are anticipating regular February maintenance will go ahead as the weather is typically poor for science and critical power infrastructure maintenance must be done at a time of year that minimizes the impact on science operations.  

Status updates will continue to be provided at least monthly, as the recovery of operations progresses. Specific capabilities and potential science observing dates will be identified after the status of antennas and other critical systems is better understood. 

The plan described above assumes that the situation in Chile and worldwide continues to improve. Regular monitoring of the pandemic evolution is performed each week. These reviews could result in advancing to the next phase in the recovery plan, maintaining the current phase, or even taking a step backwards, if necessary.

As always, the ALMA Regional Centres continue to provide support to their respective communities. If you have any questions, comments or concerns related to the situation at ALMA, please contact the ALMA Helpdesk at

We wish you, your families and colleagues continued good health and safety.