SKA Telescope specifications
The Baseline Design of SKA1
The first phase of the SKA (SKA1) was baselined in March 2013 with the publication of the baseline design document. This was then translated into formal requirements resulting in the baseline design Level 1 requirements.
Following revision, a new Design Baseline (version 2.0) with corresponding updated Level 1 requirements was produced in 2014-2015.
A further review to fit within a cost cap (Cost Control Project) was carried out in 2017 but, rather than modifying the Design Baseline, it defined a Deployment Baseline. The latter essentially identifies which capabilities to deploy from the beginning of operations and which to restore as soon as funding is available.
The baseline design Level 1 requirements are subject to formal systems engineering change control, requiring the submission of an ‘Engineering Change Proposal’ (ECP) to make changes. The ECP form can be obtained by contacting the SKAO Senior Scientists (Anna Bonaldi, Tyler Bourke or Philippa Hartley).
The top level (‘Level 0’) science requirements are intended to be consistent with the scientific capabilities of the baseline design as defined by the level 1 requirements (and may be updated to reflect adopted ECPs through their own ECP update).
SKA1-Low (also referred to as SKA-Low in public communication) will consist of 131,072 log-periodic dipole antennas distributed across 512 aperture array stations of 256 antennas each. It will be located in the Murchison Radio-astronomy Observatory, Western Australia. Around 50% of the stations will be located within a 1 km diameter core, with the remaining stations organised in clusters of 6 stations on three modified spiral arms. The maximum baseline length will be around 70 km.
SKA1-Mid (also referred to as SKA-Mid in public communication) will consist of 133 15m SKA dishes and 64 13.5m Meerkat dishes at the Karoo site in South Africa. The core will be composed of around 50% of the dishes, randomly distributed within 2 km. There are 3 logarithmic spiral arms with a maximum baseline extending out to 150 km.
(1): Part of the design baseline and deployed as a top priority
(2): Possible upgrade path (as part of Observatory Development Plan)
|Telescope||Band||Frequency Range (MHz)||Available Bandwidth (MHz)||Notes (MHz)|
|SKA1-Low||N/A||50 - 350||300||(1)|
|SKA1-Mid||1||350 - 1050||700||(1)|
|2||950 - 1760||810||(1)|
|3||1650 - 3050||1400||(2)|
|4||2800 - 5180||2380||(2)|
|5a||4600 - 8500||4000||(1)|
|5b||8300 - 15300||2 x 2500||(1)|
|6||~15000 – ~24000 (tbd)||2 x 2500||(2)|
|(A)||1600 – 5200||tbd||(2)|
|(B)||4600 – 24000||tbd||(2)|
The full SKA vision
While the focus is to deliver the SKA project as per the baseline design, with SKA-Mid in South Africa and SKA-Low in Australia, the SKAO keeps the vision of a much larger SKA alive. Such vision is sometimes referred to as SKA2 (i.e. the second phase of the SKA project), consisting in increasing both the number of elements and the baseline for each telescope (extending to other African countries in the case of SKA-Mid).
While the actual scope of SKA2 will eventually be subject to further discussions, the performance of the extended telescopes may include:
- 4-10 x SKA1 sensitivity in the frequency range of 50 – 350 MHz
- 10 x SKA1 sensitivity in the frequency range of 350 MHz – 24 GHz (including deployment of all five frequency bands)
- 50% of the “natural” sensitivity of the facility over a wide range of beam size
- 20 x SKA1 Field-of-View in the frequency range of 350 MHz – 1.5 GHz
- 20 x SKA1 maximum angular resolution in the frequency range of 50 MHz – 24 GHz