A Mission to Nature's Telescope for High-Resolution Imaging of an Exoplanet (2107.11473v1)

Abstract: The solar gravitational lens (SGL) provides a factor of $10^{11}$ amplification for viewing distant point sources beyond our solar system. As such, it may be used for resolved imaging of extended sources, such as exoplanets, not possible otherwise. To use the SGL, a spacecraft carrying a modest telescope and a coronagraph must reach the SGLs focal region, that begins at $\sim$550 astronomical units (AU) from the Sun and is oriented outward along the line connecting the distant object and the Sun. No spacecraft has ever reached even a half of that distance; and to do so within a reasonable mission lifetime (e.g., less than 25 years) and affordable cost requires a new type of mission design, using solar sails and microsats ($<100$~kg). The payoff is high -- using the SGL is the only practical way we can ever get a high-resolution, multi-pixel image of an Earth-like exoplanet, one that we identify as potentially habitable. This paper describes a novel mission design starting with a rideshare launch from the Earth, spiraling in toward the Sun, and then flying around it to achieve solar system exit speeds of over $20$ AU/year. A new sailcraft design is used to make possible high area to mass ratio for the sailcraft. The mission design enables other fast solar system missions, starting with a proposed very low cost technology demonstration mission (TDM) to prove the functionality and operation of the microsat-solar sail design and then, building on the TDM, missions to explore distant regions of the solar system, and those to study Kuiper Belt objects (KBOs) and the recently discovered interstellar objects (ISOs) are also possible.

• The paper demonstrates a novel mission design leveraging the solar gravitational lens to capture detailed, kilometer-level images of Earth-like exoplanets.
• It outlines a high-velocity propulsion strategy using solar sails and microsatellites to reach the SGL focal region within 25 years.
• The research redefines observational limits, paving the way for direct exoplanet imaging and future deep-space exploration.

High-Resolution Imaging of Exoplanets Using the Solar Gravitational Lens

The paper thoroughly examines the mission design to utilize the Solar Gravitational Lens (SGL) for resolving Earth-like exoplanets. By leveraging the immense amplification factor provided by the SGL, estimated around $10^{11}$, the mission aims to unlock imaging capabilities that dramatically surpass current technological limitations.

Mission Overview

Achieving high-resolution imaging of exoplanets using the SGL revolves around sending a spacecraft equipped with a modest telescope and a coronagraph to a focal region beginning at approximately 547 AU from the Sun. This ambitious endeavor seeks to exploit the solar lensing effect predicted by general relativity to observe detailed features of distant exoplanets—an achievement not feasible with any current ground- or space-based telescopes. The mission is framed around a novel design and propulsion strategy, emphasizing solar sails to propel a lightweight microsatellite to incredible solar system exit velocities exceeding 20 AU/year.

Technical Findings and Numerical Results

The realization of this project pivots on several key technical achievements:

• High-Velocity Mission Design: The strategy employs solar sails and microsatellites to achieve solar system escape velocities greater than the 3.5 AU/year record set by Voyager, effectively enabling traversal to the SGL focal region within 25 years.
• Imaging Potential: Once stationed, the mission proposes to collect spatially resolved data of exoplanets at resolutions estimated to reach the order of kilometers, allowing the detection of continental or oceanic-like features.
• Advanced Propulsion: By initiating a rideshare launch followed by a solar perihelion pass, the use of high area-to-mass ratio sailcraft designs facilitates the necessary velocity change without conventional propulsion.

Implications of the Research

From a theoretical standpoint, the mission could redefine our understanding of exoplanetary systems, providing the first direct imaging data for exoplanets residing tens to hundreds of light-years away. The practical implications signify a leap in our observational capabilities, potentially leading to the identification of habitability markers on distant worlds. Furthermore, the technology and methodologies explored may influence future endeavors in solar system exploration—extending to the paper of Kuiper Belt Objects (KBOs) and other interstellar phenomena.

Prospects and Future Developments

The completion of such a mission would not only advance exoplanetary science but also lay the groundwork for interstellar exploration. In preparation, incremental demonstration missions could standardize the necessary technologies, including solar sail performance and deep-space communication strategies. Moreover, extending this approach to multi-spacecraft missions may foster a new era of detail-enhanced solar and interstellar astronomy.

This research, among others, highlights the feasibility of utilizing natural gravitational phenomena to extend human observation capabilities without the need for exorbitantly large artificial structures, potentially becoming a cornerstone for future astrophysical exploration. The rigorous methodology proposed represents a calculated and feasible step for humanity towards understanding the broader universe.