Direct Multipixel Imaging and Spectroscopy of an Exoplanet with a Solar Gravity Lens Mission (2002.11871v2)

Abstract: We examined the solar gravitational lens (SGL) as the means to produce direct high-resolution, multipixel images of exoplanets. The properties of the SGL are remarkable: it offers maximum light amplification of ~1e11 and angular resolution of ~1e-10 arcsec. A probe with a 1-m telescope in the SGL focal region can image an exoplanet at 30 pc with 10-kilometer resolution on its surface, sufficient to observe seasonal changes, oceans, continents, surface topography. We reached and exceeded all objectives set for our study: We developed a new wave-optical approach to study the imaging of exoplanets while treating them as extended, resolved, faint sources at large but finite distances. We properly accounted for the solar corona brightness. We developed deconvolution algorithms and demonstrated the feasibility of high-quality image reconstruction under realistic conditions. We have proven that multipixel imaging and spectroscopy of exoplanets with the SGL are feasible. We have developed a new mission concept that delivers an array of optical telescopes to the SGL focal region relying on three innovations: i) a new way to enable direct exoplanet imaging, ii) use of smallsats solar sails fast transit through the solar system and beyond, iii) an open architecture to take advantage of swarm technology. This approach enables entirely new missions, providing a great leap in capabilities for NASA and the greater aerospace community. Our results are encouraging as they lead to a realistic design for a mission that will be able to make direct resolved images of exoplanets in our stellar neighborhood. It could allow exploration of exoplanets relying on the SGL capabilities decades, if not centuries, earlier than possible with other extant technologies. The architecture and mission concepts for a mission to the strong interference region of the SGL are promising and should be explored further.

• The paper demonstrates that leveraging the solar gravitational lens achieves light amplification up to 10^11 and an angular resolution of ~10^-10 arcseconds, enabling detailed exoplanet surface mapping.
• It outlines a mission concept deploying a 1-meter class telescope with a coronagraph beyond 548 AU, using a 'string-of-pearls' architecture for enhanced reliability and incremental technological advances.
• Numerical simulations confirm successful image deconvolution despite solar corona noise, paving the way for high-resolution spectroscopy of exoplanetary atmospheres and potential biosignature detection.

Direct Multipixel Imaging and Spectroscopy of Exoplanets Using the Solar Gravity Lens

The paper explores the innovative concept of using the Solar Gravitational Lens (SGL) to directly image and spectroscopically paper exoplanets within 30 parsecs. By exploiting the unique optical properties of the SGL, the proposed mission aims to overcome the current limitations of classical optical instruments, which are constrained by the diffraction limit and the need for exceedingly large apertures or interferometric baselines to resolve exoplanetary features.

Key Findings and Approach

The research demonstrates that leveraging the SGL yields significant advantages, such as light amplification up to a factor of ~10^11 and an ultra-fine angular resolution of ~10^-10 arcseconds for the specified wavelength, λ = 1 µm. This capability enables the construction of high-resolution images of exoplanetary surfaces, potentially up to 10 km in scale resolution from distances as far as 30 parsecs.

The mission concept involves sending a probe, equipped with a 1-meter class telescope and a coronagraph, to the SGL's focal region (>548 AU from the Sun) to obtain highly detailed images of distant exoplanets. The analysis within the paper also extends to spectrographic studies, facilitating an understanding of exoplanetary atmospheres, including potential biomarkers.

Numerical Exploration and Instrumentation

A detailed exploration of the mission architecture and design trades presents a feasible path for implementation, facilitated by advancements in solar sail technology and smallsat developments. The flexible "string-of-pearls" architecture is highlighted, enabling multiple small spacecraft to fly in formation towards and along the gravitational lens, significantly enhancing mission reliability through redundancy and allowing for successive technological advancements in each consecutive launch.

The paper presents numerical simulations demonstrating successful image deconvolution, even in the presence of solar corona-induced noise, thereby confirming the feasibility of the proposed imaging technique using the SGL.

Implications and Future Developments

The potential impact of such a mission on exoplanetary science is substantial. It could vastly improve our understanding of exoplanets by providing surface imaging and high-resolution spectroscopy that are currently beyond our technological reach with conventional methods. These advancements could lead to breakthroughs in identifying and characterizing habitable exoplanets and possibly detecting extraterrestrial life through atmospheric biosignatures.

Further technological developments foreseen in the paper, such as enhanced propulsion via solar sails, onboard AI-driven autonomy, and distributed mission architectures, position this concept within the field of feasibly ambitious NASA and international missions aimed at exploring the solar and interstellar frontiers.

Overall, the research propounds a daring yet technically grounded proposition, aligning significant advancements in theoretical optics and space technology innovation to push the boundaries of current exoplanetary imaging capabilities. The mission's conceptual design and execution plan reflect a calculated path, potentially achievable within the coming decades, advancing not only exoplanetary sciences but also the broader field of astrophysics and space exploration. As the technological foundation firms up, this approach could redefine our capabilities and strategies for distant planetary exploration.