Scientific Timeline

The scientific timeline for the SKA telescopes is linked to the construction schedule. The deployment is staged into four Array Assemblies (AA) as described below. Science Verification is planned once AA2 is ready, after which the first data will be publicly available to the community.

Construction Schedule - Array Assemblies

Array Assemblies (AAs) are milestones in the construction, providing an end-to-end telescope system with pre-defined functionality.  The roll-out of dishes and antennas continues after each AA release, so that construction is continuous.  As full funding for AA4 is not yet committed, we are following the Staged Delivery program below with a planned pause at AA*.  If full funding is secured before then, the roll-out will continue after AA*.

Below is the schedule of AAs; the expected functionality of each AA is given further down this page.  

Milestone Event
Mid Dishes 
Mid Date
Low Stations
Low Date
AA0.54 (4 SKA + 0 MeeKAT) 2025 Q442024 Q4
AA18 (8+0)2026 Q2182025 Q4


Science Verification begins 2027

68 (64+4)2027 Q3642026 Q4
AA*144 (80+64)2028 Q13072028 Q1
Operations Readiness Review 2028 Q2 2028 Q2

End of Staged Delivery 

Early Operations begin 2029 (shared risk)

 2029 Q1 2029 Q1
AA4 (Full Design Baseline SKA1)197 (133+64)TBD512TBD

Updated June 2024Note that the construction schedule is updated each month at present, and the dates in this table reflect that schedule If the "updated" date is significantly different from today's date (i.e., > 3 months), then you may wish to request an updated schedule from us.   Q1=Jan-Mar; Q2=Apr-Jun; Q3=Jul-Sep; Q4=Oct-Dec.  

Science commissioning will start as soon as the first dish/station is available on site.  

AA0.5 is the first test array for interferometry, using prototype dishes and receivers for Mid.  This is an engineering array, used to discover system level issues early and develop procedures (e.g., pointing, tracking, holography).

AA2 is the start of science verification.  The performance of SKA at AA2 is at least as good as existing facilities in many aspects, and usually better (primarily in sensitivity).   Observations with AA2 will be used to ensure the system meets the needs of science users (verification of science requirements, testing of observing modes).  The observatory will undertake some observations of known objects, and make the data available to the community (similar to the model for ALMA science verification)

The planning for scientific observations involving the science community consists of four science milestones, with dates linked to the AAs.

  1. Science Verification will start once a sufficiently capable array of dishes or stations has been deployed and tested, with “Call for Suggestions” from the community.   First data will be released to the community in 2027 following (and using) AA2.  
  2. As a transition between Science verification and normal PI observing, it’s foreseen that there could be at least one Cycle of “shared risk” PI science, which means that, should a scheduled observation be unsuccessful, there would be no guarantee that the proposal would be rescheduled. This is anticipated to happen just after testing of the AA* components and the readiness review is complete.
  3. Once the specific observation modes being offered in each time allocation cycle are fully commissioned, PI science will commence. This is anticipated to happen some months after testing of the AA* components is complete.
  4. Key Science Projects (KSP) observations are the most ambitious SKA proposals. They will typically require significantly more observing time than PI proposals, and be carried out over more than one observing cycle. This mode of observation requires a very good understanding of the telescope and maturity of the data analysis pipeline, which should be achieved two years after AA* (and then AA4) testing is complete. The process to apply for telescope time in this mode will happen however much earlier, to ensure the KSP teams are notified well in advance of their observations, and can secure the necessary resources.

With these assumptions, the broad science timeline is as follows:

Summary Timeline

Science Timeline


The increase in sensitivity of the SKA telescopes over time is illustrated in the following figure (updated March 2024).    The curves for Band 2, 5, 1 for Mid, and 200 MHz and 70 MHz for Low, shows the increase in sensitivity (A/Tsys) of these bands/frequencies as dishes/antennas are added to the arrays.  The sensitivities of some current radio telescopes is also indicated, and well as some indicative timelines (grey shades) for Commissioning, Science Verification, and Observing (PI and KSP).   (Thanks to Mark Sargent for the inspiration for this figure).  (Note the dates for the AAs on this plot are indicative and may not agree with those in the table above.  The dates on the table take precedent over dates on the plot below if they don't agree).

sensitivity over time during construction of SKA

Functionality of each Array Assembly

Below is listed the functionality expected for AA2 (science verification - first public data to the community) and AA* (shared-risk observations).  Note that while the functionality will be scientifically verified, the modes available for science observations may be limited.   Please see the "Observing with SKA" page for details as they become available.

Functionality of AA2

AA2 Functionality

Functionality of AA*

AAstar Functionality
Last modified on 09 July 2024