LI Optical Lensing (LOL): Using the Earth as an Atmospheric Lens

The Terrascope concept was first introduced by D. Kipping in 2019, and it has increasingly gained scientific attention. This concept uses a satellite at Lagrange point 1 and involves using Earth's atmosphere as a lens to amplify light from distant astronomical bodies. If successful, the Terrascope could revolutionise deep space observation by enhancing angular resolution and amplification. Indeed, in previous studies, D. Kipping determined an estimated amplification of order 22,500: the computed amplification decreased after accounting for the effects of turbulence, absorption, transmission, and scattering of Earth's atmosphere, and the estimated image reconstruction was performed taking into account Earth's oblateness. On these premises, 'LI Optical Lensing (LOL)' mission is carried out and aims to characterise the amplification and the resolution of the Terrascope concept by using a satellite placed at a Hill radius distance from Earth, serving both as a technological and scientific demonstration. This study was initially conducted during ESA's CubeSat Summer School 2024 in ESEC using a Model-Based Systems Engineering approach with the COMET tool and ESA expert support. The proposed satellite would be launched as a secondary payload on the Ariane 62 rocket in 2030, alongside ESA's NEOMIR mission. The first presented system analysis resulted in a 12U CubeSat design at both system and subsystem levels, including system budgets and subsystem analyses. The optical payload consisted of visible and infrared detectors aiming to observe distant celestial objects in the anti-sun direction, such as high-redshift objects, active galactic nuclei, radio galaxies and exoplanets. In the subsequent iterations, the scale-up to a micro-satellite has emerged as the optimal solution due to payload constraints. In particular, a tailored payload ray-tracing design combined with AOCS fine guidance logic has been investigated. Additionally, from a cost perspective, the main benefit of this concept is that it tackles the crisis in astronomy of making ever-larger space and ground-based telescopes. For instance, the upcoming Extremely Large Telescope (ELT) has an aperture diameter of 39 m and comes at a cost of 1.4B. Studies from D. Kipping predicted that a Terrascope of 1 m aperture diameter, placed at a Hill radius distance from Earth, could achieve the same amplification as a 150 m telescope on Earth, which would cost 50-100B. Therefore, using natural lensing instead of building ever-growing apertures could lead to comparable results in deep-space observation, at a fraction of the cost.