[Paper Review] Flying on a Rainbow: A Solar-Driven Diffractive Sailcraft

Grover A. Swartzlander|arXiv (Cornell University)|May 15, 2018

Aerospace Engineering and Energy SystemsEngineering17 citations

TL;DR

This paper proposes a solar-driven diffractive sailcraft that uses a transmissive subwavelength grating to harness radiation pressure from broadband sunlight, achieving 83% conversion of the solar spectrum into momentum. Theoretical and numerical analysis shows it can enable efficient orbit-raising with potential advantages over reflective sails in efficiency and spectral utilization.

ABSTRACT

Radiation pressure afforded by natural broadband sunlight upon a transmissive diffractive sail is theoretically and numerically investigated. A grating period of one micrometer is found to convert 83% of the solar black body spectrum into sailcraft momentum. Non-optimized orbit-raising trajectories for diffractive and reflective sails are compared. Potential advantages of diffractive sails are also described.

Motivation & Objective

• To investigate the feasibility of using transmissive diffractive sails to harness radiation pressure from natural sunlight.
• To analyze how a subwavelength grating structure can efficiently couple broadband solar radiation into momentum transfer for spacecraft propulsion.
• To compare the performance of diffractive sails with traditional reflective sails in orbit-raising trajectories.
• To identify potential advantages of diffractive sails in spectral response, material efficiency, and mission design.

Proposed method

• The study employs theoretical and numerical modeling of a transmissive diffractive sail with a grating period of 1 micrometer.
• Radiation pressure is calculated using electromagnetic theory applied to a broadband solar blackbody spectrum.
• The momentum transfer efficiency is evaluated by analyzing the diffraction efficiency of the grating across the solar spectrum.
• Orbit-raising trajectories are simulated and compared between diffractive and reflective sail configurations.
• The analysis focuses on the spectral response of the grating to maximize momentum transfer across the visible and near-infrared spectrum.
• The model assumes idealized optical properties and neglects thermal and structural effects for initial performance assessment.

Experimental results

Research questions

• RQ1 Can a transmissive diffractive sail efficiently convert broadband solar radiation into directed momentum for spacecraft propulsion?
• RQ2 What is the maximum momentum transfer efficiency achievable with a subwavelength grating under natural sunlight?
• RQ3 How does the performance of a diffractive sail compare to a reflective sail in terms of orbit-raising capability?
• RQ4 What spectral and geometric parameters optimize momentum transfer in a diffractive sail?
• RQ5 What are the potential mission advantages of using diffractive sails over conventional solar sails?

Key findings

• A subwavelength grating with a period of 1 micrometer achieves 83% efficiency in converting the solar blackbody spectrum into sailcraft momentum.
• The diffractive sail design demonstrates superior spectral utilization compared to reflective sails, particularly in the visible and near-infrared regions.
• Numerical simulations show that non-optimized orbit-raising trajectories for the diffractive sail are competitive with those of reflective sails.
• Theoretical analysis confirms that radiation pressure can be harnessed effectively through engineered diffraction rather than reflection.
• The study identifies potential advantages in material efficiency, reduced mass, and enhanced spectral response for diffractive sailcraft.