Solar Sail Research Articles

Optimal guidance laws for diffractive solar sails with Littrow transmission grating

The use of advanced and highly engineered membrane films in solar sail design enables the thrust vector to achieve some specific characteristics that are capable of affecting the performance of a sail-based spacecraft trajectory in a transfer mission scenario. In this field, the recently proposed diffractive sail uses metamaterial films to coat the very thin sail membrane as a potential and effective (in some mission scenarios) alternative to the more common metallic reflective coating. The purpose of this work is to study the optimal guidance law, as a function of sail pitch angle, of a diffractive sailcraft with a Littrow transmission grating film in a typical two-dimensional heliocentric transfer. In particular, the optimal steering law is obtained through a classical indirect approach, depending on the characteristics of Lawden's primer vector, either in exact (by numerical simulation) or approximate (by analytical means) form. The performance of a diffractive sailcraft with a Littrow transmission grating film is then analyzed in a number of potential mission scenarios such as, for example, a phasing in a circular orbit, an interplanetary transfer between coplanar Keplerian trajectories, a circular orbit flip maneuver, and an escape from the Solar System. Simulation results indicate that this specific diffractive sailcraft is potentially capable of executing a typical solar sail-based mission scenario with a simple steering law.

Design, modeling and experimental investigation of a novel solar sail with high area-to-mass ratios for efficient solar sailing

Solar sailing is a promising propellant-free approach to propelling spacecraft in space. However, the propelling efficiency of conventional solar sail spacecraft is limited by their area-to-mass ratios. This paper proposes a novel design of micro solar sails with area-to-mass ratios above 100 m2/kg for next-generation chip-scale spacecraft. Bilayer thin films developed by Microelectromechanical Systems (MEMS) technologies were patterned into grid microstructures, and theoretical analysis of a sail prototype was conducted. The electro-thermal and thermo-mechanical models of the solar sail in geospace were established by taking effects of Joule heating, solar radiation, and thermal re-emission into consideration, enabling rapid prediction of its three-dimensional (3-D) reconfiguration from the as-released two-dimensional (2-D) microstructure. Adjustment of the ChipSail’s acceleration arising from the sail’s morphing was also analytically modeled. Fabrication and characterization of the sail prototype made of multiple Al/Ni50Ti50 bilayer beams were accomplished. In-situ SEM imaging of the sail prototype in vacuum chamber witnessed an active and continuous 3-D reconfiguration under Joule heating, and over 90° deformation was detected by applying a DC voltage of 0.078 V. Theoretical and experimental work on the solar sail with at least 10 times higher area-to-mass ratios than conventional ones will lay a solid foundation for efficient solar sailing.

Superluminal Spaceflight, Negative Mass, Closed Time Like Curves, Manipulation of Inertia by Advanced Electromagnetic Fields and Speculations on Time and Energy

It is known that light photons in a laser can accelerate a spacecraft imparting momentum upon a light sail, here one considers the properties of superluminal nature of light as shown in many experiments, where the momentum of superluminal laser theoretically might accelerate a spacecraft faster than light. Next one considers a patent on time travel creating negative mass, one speculates upon this, with references to experiments that have created negative mass. Then one considers post-selection in relation to set up an experiment that uses 3 quantum states, entangled particles to create a loop in time of a closed time like curve. Then there is presented experiments done, where manipulation of inertia by advanced electromagnetic fields produces thrust, I suggest with this, by feeding advanced energy into such a device to produce thrust through time not space. And lastly there are speculations of time and energy, where energy is considered as a dimension.

Solar Sail Trajectory Design with Pulsed Radial Thrust

Solar Sail Trajectory Design with Pulsed Radial Thrust

Controlling the orbital motion of the spacecraft near the libration point by changing the solar sail reflectivity

Controlling the orbital motion of the spacecraft near the libration point by changing the solar sail reflectivity

On the Deformation of a Round Three-layer Plate under the Action of a Surface Charge

In this work there are the charging model and the results of calculations of electric charge density on the surface of the solar sail in the space. These results are used to estimate change of a sail form as a result of its electrifying in space plasma of solar system.

Eco-friendly synthesis of high-performance polyimide materials using bio-based greener solvents: Towards sustainable technologies in space environment

Polyimide-based materials offer high thermal stability, mechanical strength, and resistance to UV and solar radiation, making them ideal candidates for use in demanding space missions. In particular, polyimide membranes find practical application in large deployable and inflatable structures, as well as in solar propulsion sails for deep space missions. In this work, thermally stable polyimides with fully aromatic structure and trifluoromethyl functional groups were synthesized by a two-step method using bio-based alternative solvents, namely dimethyl isosorbide (DMI) and dihydrolevoglucosenone (Cyrene). These solvents are considered environmentally friendly and greener alternatives compared to conventional dipolar aprotic solvents like dimethylacetamide (DMAc). Using the in-house-made aromatic polyimides, membranes were fabricated and their properties were compared to those made of PI synthesized using conventional routes in DMAc. Different routes for solvent removal were investigated during membrane fabrication. Several key characteristics were considered to assess the effect of using greener solvents on the final properties of the polyimide materials, including hydrophobicity degree from water contact angle (WCA), thermal behavior from differential scanning calorimetry (DSC), and viscoelastic properties from dynamic-mechanical analysis (DMA). These analyses provide insights into the thermal and mechanical response of the PI materials under varying temperatures and loads, which is essential for designing structures that can withstand the harsh conditions of space, such as in solar sail propulsion systems.

Shape recovery simulation of viscoelastic thin-ply composite coilable booms

Coilable booms made of thin-ply composites provide mass and volume efficiency for deploying large structures in space. The recovered shape of the booms after being stowed in the coiled configuration is critical to the deployed stiffness and shape precision of the spacecraft, but is heavily influenced by the viscoelasticity of the polymer composites. A numerical study of coiling, stowing, uncoiling and shape recovery of a viscoelastic thin-ply composite coilable boom is presented in this paper. The formulation of two micromechanics-based viscoelastic shell models and their numerical implementation in structural simulations are presented. The shape recovery of a composite boom coiled for two years, replicating the typical timeline for deployable structures used in solar sail missions, has been simulated. The demonstrated modeling and simulation capability is useful for designing deployable spacecraft structures.

Reflection from Inclined, Relativistic Light Sails

We present a new formula for relativistic reflection of solar radiation from a light sail moving at a velocity v inclined at an arbitrary angle θ, using an elementary two-body analysis. The formula is shown to reduce to the formulas of Euclid, Einstein, and Gjurchinovski in the relevant limits. Our results are of relevance for computing optimal geometries for relativistic light sails.

Different effects of perturbations (solar sail) on The motion of the test particles in cr3bp

"The idea of solar sail is used to investigate the motion properties of the test particle which is varying its mass according to the Jeans law and moving under the gravitational forces of the primaries, the Coriolis and centrifugal forces in the circular restricted three-body system (CRTBS). The equations of motion of the test particle are determined under the above said perturbations. And hence, the dynamical properties like the locations of equilibrium points, their stability, periodic orbits, Poincare surfaces of section and basins of attracting domain are investigated. This problem will help those researchers who are interested in studying the problem related to solar sail for space Missions."

Study on Displaced Orbits Below the Moon’s South Pole Near L2 Point Based on Solar Sail

This work explores displaced orbits of solar sails below the Moon’s south pole, near the L2 libration point in the Earth-Moon system. Light pressure provides acceleration for displaced orbits. These orbits enable continuous communication and observation of the Moon’s south polar region, where a lunar base is planned. Linearized dynamic equations yield analytical solutions of displaced orbits, which are either quasi-periodic or periodic. Quasi-periodic orbits have varying altitudes of hundreds of kilometers and a period of about a year, while periodic orbits have fixed altitudes аnd the same period. A sliding mode controller maintains the orbits using sail attitude angles and reflectivity as control variables. With a reflective area to mass ratio of 18 m2/kg, the displaced heights of quasiperiodic and periodic orbits near L2 are 2010.38 km and 2210.06 km, respectively. Numerical simulations confirm the controller’s effectiveness for both orbit types

Diffractive Sail-Based Displaced Orbits for High-Latitude Environment Monitoring

This paper analyzes the possibility of maintaining a circular displaced non-Keplerian orbit around the Sun by means of a Sun-facing diffractive sail. With the goal of monitoring the Earth’s high-latitude regions, the spacecraft is required to track its displaced orbit at an angular velocity equal to the mean motion of the planet. In doing so, the spacecraft keeps a constant average phase shift with respect to Earth’s angular position along its orbit, allowing the objectives of the scientific mission to be achieved. The diffractive sail, recently proposed by Swartzlander and chosen in this paper as the spacecraft’s primary propulsion system, is a special photonic solar sail in which the membrane film is covered by an advanced diffractive metamaterial. In particular, a Sun-facing diffractive sail with a grating at normal incidence generates radial and transverse thrust components of equal magnitude; that is, the thrust vector is tilted 45 degrees from the Sun-spacecraft line. This peculiarity enables the diffractive sail to maintain a family of circular displaced non-Keplerian orbits, each of which is characterized by unique values of radius and a lightness number for an assigned value of spacecraft displacement relative to the Ecliptic. A comparison with the ideal reflecting sail shows that the diffractive sail performs better because for the same overall spacecraft mass, the latter needs about 30% less surface area exposed to the Sun. Finally, this paper discusses the classical stability problem, assuming an error in orbit insertion of the diffractive sail-based spacecraft. In this context, extensive numerical simulations show that such displaced orbits are marginally stable.

Low-cost Mars transfer from the Earth using solar sails and lunar swing-bys

Low-cost Mars transfer from the Earth using solar sails and lunar swing-bys

Optimal geometry for lunar swing-by maneuvers aided by solar sails in the restricted four-body problem

Optimal geometry for lunar swing-by maneuvers aided by solar sails in the restricted four-body problem

Study of orbital relocation of objects in GEO via orbital perturbations and solar sail

Study of orbital relocation of objects in GEO via orbital perturbations and solar sail

Solar sail dynamics in the Sun–Earth system: effects of SRP in the Earth Hill’s region

Solar sail dynamics in the Sun–Earth system: effects of SRP in the Earth Hill’s region

Smart Composite Booms for Solar Sails

Composite booms for solar sails have been prototyped by using innovative smart materials. Shape memory polymer composites (SMPCs) have been manufactured by interposing SMP layers between carbon-fiber-reinforced (CFR) plies. A polyimide membrane has been embedded into the CFR-SMPC frame of the sail during lamination. The sail’s size has been limited to 250 × 250 mm2 to allow its testing on Earth. The feasibility of large sail deployments has been shown by prototyping small CFR-SMPC elements to insert only in the folding zones. Numerical simulation by finite element modeling allowed for predicting the presence of wrinkles close to the frame’s vertexes in the cases of large sails under solar radiation pressures. Nevertheless, the frame’s configuration, with SMPC booms at all the edges of the sail membrane, seems to be suitable for drag sails instead of propulsion. On-Earth recovery tests have been performed on 180° folded sails by using flexible heaters. After an initial induction time, the maximum rate was reached with a following drop. In the case of two heaters per folding zone, the angular recovery rate reached the maximum value of about 30 deg/s at the power of 34 W, and full recovery was made in 20 s.

BLISS: Interplanetary exploration with swarms of low-cost spacecraft

Leveraging advancements in micro-scale technology, we propose a fleet of autonomous, low-cost, small solar sails for interplanetary exploration. The Berkeley Low-cost Interplanetary Solar Sail (BLISS) project aims to utilize small-scale technologies to create a fleet of tiny interplanetary spacecraft for rapid, low-cost exploration of the inner solar system. This paper describes the hardware required to build a ∼10 g spacecraft using a 1 m2 solar sail steered by micro-electromechanical systems (MEMS) inchworm actuators. The trajectory control to a NEO, here 101955 Bennu, is detailed along with the low-level actuation control of the solar sail and the specifications of proposed onboard communication and computation. Two other applications are also shortly considered: sample return from dozens of Jupiter-family comets and cometary nuclei imaging. The paper concludes by discussing the fundamental scaling limits and future directions for steerable autonomous miniature solar sails with onboard custom computers and sensors.

Acquisition and integration of differential pressure measurements on sails for boat performances improvement

In this paper, we integrated within a specifically developed acquisition system, denoted as Oceanus, the measurements from a differential pressure sensor between the two sides of a sail (windward and leeward sides); experiments have been performed using a light jib sail of a 35 feet cruising-racing yacht. We analyzed the correlation between such a signal and other standard signals usually present on board such as boat speed, intensity and direction of apparent or real wind; moreover, data from Inertial Measurement Units are handled. We also considered the Target Data, which depend on the actual point of sail, and the discrepancy between measured data and the predicted Targets is monitored as an error in terms of the true wind angle and boat velocity. In this way, the trimmer/helmsman can monitor the differential sail pressure together with Target data and decide to reduce the error with a correction in how sails are trimmed, rather than in how the boat is steered to achieve an improvement of boat performances. The resulting telemetry system represents an effective low cost solution, which is affordable even for amateur yachtsmen.

An Initial Investigation of Students’ Understanding of Space Exploration

The topic of space exploration receives little attention in most introductory astronomy courses. However, students come to such courses with both an interest and ideas informed by popular media–ideas that may or may not be consistent with scientific and engineering outlooks. This study explored what students recall about space exploration ideas after engaging with two short, in-class activities on the possibility of travel to Mars and the use of solar sails for exploration. We asked four open-ended questions for extra credit and coded students’ responses ($N$ = 106 to 150) for themes. Coding demonstrated that students had reasonable, if limited, understanding of factors influencing both crewed and uncrewed mission types as well as risks to crews after completing these activities.