Refinement of STARE for the ESA mini-F program

At the top of scientific priorities for large missions at both ESA and NASA is direct imaging and spectroscopy of Earth-like planets in the habitable zones of Sun-like stars, for the purpose of investigations of habitability and life in the universe.

Such missions will operate most efficiently if they can investigate planets that have already been detected by previous missions. The by far most valuable pre-dicoveries in this context are planets in the most nearby stellar systems.

However, the very most nearby planets are not suitable for detection with the most commonly applied planet-finding techniques, such as transits.

The STARE mission is a concept for a small satellite with the capacity to detect planets in nearby binary systems, and in particular, to detect Earth-like planets in the habitable zones around the nearest Sun-like neighbours alpha Centauri A and B. STARE was developed and is being led by Swedish researchers.

The satellite would fit neatly into the envisioned mini-F satellite program being investigated through an exploratory call by ESA. A central component of STARE is a Wollaston-like prism with a very high thermal stability.

In preparation for the ESA mini-F call, we here propose to conduct an investigation to show that the Wollaston-like prism, which has excellent performance and feasibility on paper, can be implemented also in reality, based on products that are available in the commercial market.

The key outputs of the investagation will be a cost estimation corresponding to a precisely defined set of specifications for a deliverable prism, and a uniform model for the full optical system including the prism.

The study would be performed in advance of the ESA call deadline in May, and would greatly aid in demonstrating the feasibility and commercial availability of the satellite concept to ESA.

With the ability to pre-screen the best possible science targets for planets, STARE has the potential to greatly enhance the efficiency and corresponding scientific output of future envisioned large-scale exoplanet missions of ESA and NASA, at a miniscule fraction of their mission costs. STARE would also provide planet masses, which are not attainable by the aforementioned large-scale missions.