HARMONI is the first light integral field spectrograph for the ELT. It includes a core 'science instrument' -- the IFS -- supported by a range of other systems, in particular adaptive optics sensors for SCAO and LTAO. The latter was, for many years, treated as an entirely separate instrument with the ELT observatory architecture. A better understanding of the technical challenges, together with a changing political and funding environment, led to merger of the two projects in 2014. The project now rates over 400FTE with a commensurately large hardware budget.
The IFS part of the instrument, at least in function, remains largerly unchanged since 2009 when the consortium completed a Phase A study as part of the (then 42m) E-ELT instrument studies. The structure of the consortium was essentially fixed then, and many firm (and soft) contractual agreements and understandings limit the flexibility to match work to product. Over the years however, as the ELT project has evolved, the design and scope of HARMONI has changed and expanded. This has brought new partners into the consortium, changed the design concept of the instrument, introduced new interfaces, and updated requirements. To further complicate matters, as of PDR (late 2017) the final scope of the project is still open due to funding uncertainties.
All of these factors have made the development of a system architecture particularly challenging. The architecture of 2009 - whilst ultimately linked to the structure of the consortium - is no longer fit for the technical purpose. A revised system architecture, and the resulting product breakdown structure, have had to be carefully adapted to satisfy a wide range of constraints. It must be solid enough to allow the project to progress clearly, but flexible enough to deal with what changes may lie ahead.
We have applied systems engineering processes to develop and architecture which is clean and robust, whilst including some inevitable compromise driven by overall project considerations. The paper will describe the processes we have followed, how the architecture has evolved, and how we have dealt with constraints and compromises forced by the existing consortium structure. We will present the baseline architecture for HARMONI, and explain how this maps onto other areas of the project and the overall instrument development process. This is an example of system architecting in the real world of moving targets and immovable obstructions.
HARMONI is the E-ELT’s first light visible and near-infrared integral field spectrograph. It will provide four different spatial scales, ranging from coarse spaxels of 60 × 30 mas best suited for seeing limited observations, to 4 mas spaxels that Nyquist sample the diffraction limited point spread function of the E-ELT at near-infrared wavelengths. Each spaxel scale may be combined with eleven spectral settings, that provide a range of spectral resolving powers (R ~3500, 7500 and 20000) and instantaneous wavelength coverage spanning the 0.5 – 2.4 μm wavelength range of the instrument. In autumn 2015, the HARMONI project started the Preliminary Design Phase, following signature of the contract to design, build, test and commission the instrument, signed between the European Southern Observatory and the UK Science and Technology Facilities Council. Crucially, the contract also includes the preliminary design of the HARMONI Laser Tomographic Adaptive Optics system. The instrument’s technical specifications were finalized in the period leading up to contract signature. In this paper, we report on the first activity carried out during preliminary design, defining the baseline architecture for the system, and the trade-off studies leading up to the choice of baseline.
The Key Technology Network (KTN) within the OPTICON programme has been developing a roadmap for the
technology needed to meet the challenges of optical and infrared astronomy over the next few years, with particular
emphasis on the requirements of Extremely Large Telescopes. The process and methodology so far will be described,
along with the most recent roadmap.
The roadmap shows the expected progression of ground-based astronomy facilities and the technological developments
which will be required to realise these new facilities. The roadmap highlights the key stages in the development of these
In some areas, such as conventional optics, gradual developments in areas such as light-weighting of optics will slowly
be adopted into future instruments. In other areas, such as large area IR detectors, more rapid progress can be expected as
new processing techniques allow larger and faster arrays. Finally, other areas such as integrated photonics have the
potential to revolutionise astronomical instrumentation.
Future plans are outlined, in particular our intention to look at longer term development and disruptive technologies.