{"id":"1be3a97b-88a1-4c21-be57-acb3a3125805","arxiv_id":"2608.04596","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":7.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":2,"one_line_summary":"Sun-facing diffractive sails can generate H-reversal trajectories that hit Apophis with roughly 21% more impact velocity and 35% shorter flight time than reflective sails, with a two-stage control adding more speed.","lead":"This paper proposes using a Sun-facing diffractive sail, which redirects sunlight through microscopic gratings, to quickly reverse its orbit and smash into an asteroid. Simulations of an Apophis impact show impact speeds near 100 km/s in under a year, faster than traditional reflective-sail designs.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The headline performance claims depend on the ideal diffraction-grating model of Eq. (3), which assumes 100% single-order efficiency; real diffractive sails lose efficiency, especially near theta_d = -90 degrees, where the two-stage strategy's gain is largest.","rationale":"The paper's central claim is a quantitative performance comparison, not merely a proof that H-reversal trajectories exist for SFDS. That comparison is computed entirely from the ideal efficiency factors in Eq. (3). The reader's conditional verdict already identifies the ideal model as the weakest assumption, and I agree. I considered whether a more fundamental mathematical flaw exists, such as the hodograph singularity at h=0 or the 2D coplanar approximation. The h=0 treatment is consistent with prior H-reversal literature (Refs. [29,44]), and the 2D assumption is symmetric between SFDS and RS, so it does not threaten the relative claims. The lack of code and data is a reproducibility issue but not a correctness objection to the argument itself. Thermal safety is handled only through the r_p,target constraint, and setting r_p,target=0.3 AU without a thermal model is an engineering gap; however, the central theoretical claim is independent of a specific material temperature limit. The efficiency sensitivity is the single most load-bearing issue because it enters every headline number. The proposed test -- re-optimizing with a two-order loss model -- would directly show whether the SFDS advantage survives realistic optical performance. If the test shows the advantage disappears, the verdict should move toward rejection or unverified status; until then, the reader's CONDITIONAL verdict is appropriate and needs no change.","tokens_in":21020,"tokens_out":8858,"duration_ms":110561,"concrete_test":"Recompute the beta=0.70 one-stage and beta=0.62 two-stage Apophis trajectories (Figs. 13 and 17) using a two-order diffraction model: let a fraction gamma of the optical power go into the +1 order and (1-gamma) remain in the undiffracted order, with gamma=0.85 at theta_d=0 and gamma decreasing linearly to 0.5 at |theta_d|=90 degrees (or use measured LCPG efficiency data); recompute eta_n and eta_p from the vector sum of the two orders, re-optimize launch epoch using Algorithms 3 and 4, and compare velocity and TOF against the ideal-model results. If the SFDS advantage over RS falls below 10% in velocity or 15% in TOF, the headline performance claims are not robust to realistic optical losses.","verdict_should_be":"UNCHANGED","load_bearing_attack":"Section II.A adopts the ideal diffraction-grating model (Eq. 3) with eta_n = 1 +/- cos(theta_d) and eta_p = sin(theta_d), implying that all incident photons are redirected into a single diffraction order with no optical loss. This assumption is load-bearing because every quantitative result in the paper -- the 21% impact-velocity increase, the 35% mission-time reduction, and the 9-19 km/s two-stage gain -- is computed from these efficiency factors. Real diffractive sails, including the LCPG architectures cited in Refs. [46,47], have finite diffraction efficiency, Fresnel interface losses, and a residual zero-order component, with efficiency typically degrading as the diffraction angle approaches +/-90 degrees. The two-stage strategy explicitly drives theta_d2 toward -90 degrees (Section V.C), precisely the regime where the ideal model is most optimistic. If realized eta_p at large |theta_d| is substantially below sin(theta_d), the transverse acceleration during the SPA phase drops, reducing H-reversal efficiency and impact velocity. The SFDS advantage over RS could then narrow or vanish. The paper acknowledges the idealization ('for simplicity, we use ideal models', Section II.A) but presents the resulting numbers as mission performance rather than as an upper-bound sensitivity study.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper proposes using a Sun-facing diffractive sail (SFDS) to perform angular-momentum-reversal (H-reversal) trajectories for rapid, high-velocity asteroid kinetic impact missions. Two control strategies are studied: a one-stage strategy with constant diffraction angle \\theta_d and a two-stage strategy that switches \\theta_d once near the angular-momentum reversal. Using the hodograph method, the authors map feasibility regions in the (\\beta,\\theta_d) parameter space for R-type and T-type SFDS and for a conventional reflective sail, under an optional perihelion constraint. They then develop trajectory design algorithms: a Perihelion-Constrained Phase-Matching Algorithm for the one-stage strategy and a dimensionality-reduced SQP optimization for the two-stage strategy. The methods are applied to an Apophis impact scenario, reporting that at \\beta=0.70 and r_{p,target}=0.3 AU the one-stage SFDS increases impact velocity by 21% and reduces mission duration by 35% relative to a reflective sail, while the two-stage strategy provides an additional velocity gain (9 km/s in the abstract, up to 19 km/s at \\beta=0.62 in Section V.C). The paper concludes that SFDS H-reversal trajectories offer a feasible baseline for emergency planetary defense.","tokens_in":21232,"tokens_out":4009,"duration_ms":48090,"significance":"If the reported performance holds under realistic physics, this is a useful contribution to the solar-sail trajectory literature and to planetary-defense mission analysis. The paper's strengths include a systematic hodograph-based feasibility mapping, clearly specified algorithms (Algorithms 1-4), an explicit comparison with the earlier RS H-reversal result of Gong et al., and a transparent treatment of free parameters (\\beta and r_{p,target}). The two-stage \\theta_d strategy is a sensible way to combine a perihelion-constraint-compatible first stage with a high-transverse-thrust second stage, and the warm-start strategy using neighboring-\\beta solutions is well motivated. The paper does not fit any result to a pre-specified target: impact velocities are outputs of optimization under stated constraints. The main caveat is that all quantitative conclusions rest on the ideal diffraction-grating force model, so the headline numbers should be read as upper-bound performance estimates unless accompanied by a realistic-efficiency sensitivity analysis.","major_comments":[{"comment":"The ideal diffraction-grating model with \\eta_n=1\\pm\\cos\\theta_d and \\eta_p=\\sin\\theta_d assumes that all incident photons are redirected into a single diffraction order with no optical losses. This assumption is load-bearing: every quantitative headline claim—the 21% velocity increase, the 35% mission-time reduction, and the 9-19 km/s two-stage gain—is computed from these efficiency factors. Real diffractive sails, including the cascaded LCPG architectures cited in Refs. [46-48], have finite diffraction efficiency, Fresnel interface losses, and a residual zero-order component, with efficiency typically degrading as the diffraction angle approaches \\pm90°. The two-stage strategy explicitly drives \\theta_d2 toward -90° (Section V.C), which is precisely the regime where the ideal model is most optimistic. The paper should include a sensitivity study with realistic efficiency curves, or explicitly reframe the numerical results as an idealized upper-bound analysis rather than as mission performance predictions.","section":"§II.A, Eq. (3)"},{"comment":"The paper claims to establish 'sufficient and necessary conditions' for SFDS H-reversal trajectories, but the feasibility regions in Figs. 5 and 8 are obtained by numerical grid classification, not by proof. In particular, Algorithm 1 relies on the statement that 'numerical analysis confirms that r_p decreases monotonically as \\theta_d becomes more negative' for R-type SFDS; no proof or error bound is given for this monotonicity over the entire feasible domain. Similarly, the two-stage analysis in Section III.C uses a discrete grid of N=100 values and a region-membership test that is checked only at grid points. The authors should either provide analytical arguments for the topological classification and monotonicity, or soften the 'necessary and sufficient' claim to 'numerically verified feasible regions over the surveyed grid.'","section":"§III.B, §III.C"},{"comment":"There is a factual discrepancy in the reported two-stage performance gain. The abstract states that the two-stage strategy 'yields an additional 9 km/s gain in impact velocity,' while Section V.C states that at \\beta=0.62 'the two-stage strategy delivers a massive velocity increment of up to 19 km/s.' The conclusion also quotes a range of '100-106 km/s' for the two-stage strategy. This inconsistency must be resolved, and the final reported numbers should be consistent across the abstract, the main text, and the conclusion.","section":"Abstract and §V.C"},{"comment":"The analysis assumes a strict Sun-facing attitude with no attitude drift, negligible \\theta_d switching time, and 2D coplanar dynamics for the Earth-Apophis-SFDS system. These idealizations are acknowledged but not validated. In particular, the most severe thermal and attitude-control conditions occur exactly at the 0.3 AU perihelion where the SPA phase generates most of the reported energy gain. The paper would be strengthened by an engineering feasibility check for the 0.3 AU close approach (thermal limits, attitude stability under non-ideal torques) and by a quantitative estimate of how attitude errors or switching delays affect the terminal impact velocity. Without such an assessment, the claimed 'rapid-response, high-kinetic-energy architecture' remains a theoretical upper bound.","section":"§II.B, §V.A"}],"minor_comments":[{"comment":"The constraint g_1=v_t(t_f)\\le 0 uses the symbol v_t, but the state vector is defined with radial and transverse components v_r and v_\\theta. Please define v_t explicitly or use v_\\theta consistently.","section":"§IV, Eq. (11d)"},{"comment":"The parameter \\eta in Eq. (7) is a different quantity from the force efficiency \\eta_n used in Eq. (2). This reuse of the symbol \\eta may confuse readers; a distinct symbol such as \\kappa for the hodograph parameter would improve clarity.","section":"§III.A, Eqs. (7)-(9)"},{"comment":"The while-loop condition 'not optimal' is informal. Specify a concrete convergence criterion, such as a tolerance on the gradient of the Lagrangian or on the step size of the SQP iteration.","section":"§IV.B, Algorithm 4, line 6"},{"comment":"The condition '(v_sw,w_sw)\\in Region 3' should clarify that Region 3 refers to the v-w phase-space region defined in Section III.A, not the parameter-space regions labeled 1-6 in Fig. 5. This is likely clear to the authors but may mislead a reader.","section":"§III.C, Algorithm 2, line 7"},{"comment":"Reference [6] contains a corrupted character sequence ('VokrouhlickÃ1/2') that should be corrected to the proper spelling of the author's name.","section":"References"},{"comment":"The text says 'the flight time of the SFDS is shortened by a full 300 days compared to the RS at \\beta=0.66' and then 'still reduces the flight time by nearly 200 days at \\beta=0.70.' These two statements are in the same paragraph and would be easier to verify if the corresponding values were annotated directly on Fig. 13b.","section":"§V.B, Fig. 13"}],"recommendation":"major_revision","confidential_remarks":"The paper is within the scope of the journal and the hodograph-based methodology is sound in outline. The main risk is that the reported performance numbers are treated as mission-level predictions despite resting on the ideal diffraction model; the authors should be asked to add a sensitivity analysis or to clearly label the results as idealized upper bounds. The discrepancy between the abstract's 9 km/s and Section V.C's 19 km/s two-stage gain also needs to be fixed before publication. I see no issue with novelty or circularity: the SFDS-specific feasibility mapping and design algorithms are new relative to the cited RS work."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick take: this is a solid mission-design study that brings diffractive sails into the H-reversal trajectory family, with a genuine new control strategy (two-stage theta_d) and a clean feasibility mapping. The headline numbers—21% velocity gain, 35% time reduction, up to 19 km/s extra from the two-stage strategy—are computed under an ideal diffraction-grating model that the paper itself flags as ideal. That model is the load-bearing assumption, and the two-stage strategy pushes theta_d2 close to -90 degrees, exactly where real liquid-crystal polarization gratings lose efficiency. So the absolute performance numbers are upper bounds, not predictions. That said, the relative comparison to RS is still meaningful as a first-order estimate, and the paper does not hide the idealization; it just doesn't test how sensitive the results are to efficiency degradation. A sensitivity sweep with eta_p scaled by 0.8 or 0.9 would strengthen it a lot.\n\nWhat's genuinely new: first application of SFDS to H-reversal; the two-stage theta_d control law with a single switching event; the feasibility domain characterization under perihelion constraints; the Perihelion-Constrained Phase-Matching algorithm; and a Pareto front for the velocity/TOF trade-off. The hodograph reduction is standard, and the algorithms are well-specified enough to reproduce. No code or data, but the integration steps are clear.\n\nSoft spots, in order: (1) the ideal force model, as above; (2) the claim of 'necessary and sufficient' conditions is based on a high-resolution grid classification, not a proof—fine for design charts, but the language overreaches; (3) the 2D coplanar approximation for Earth and Apophis is a simplification but consistent with the cited RS baseline; (4) the abstract's 9 km/s two-stage gain is the beta=0.7 case, while the text reports 19 km/s at beta=0.62—worth a consistency check.\n\nOverall: the central argument holds under its stated assumptions. The paper deserves a serious referee and would benefit from a sensitivity analysis on the sail efficiency model before acceptance.","headline":"Bringing diffractive sails to H-reversal is a real step forward, but the headline gains are upper-bound numbers from an ideal efficiency model; worth refereeing with a sensitivity analysis required.","tokens_in":21813,"tokens_out":2307,"would_cite":true,"duration_ms":26383,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"A Sun-facing diffractive sail can reverse its orbit and hit Apophis harder and sooner than a reflective sail.","keywords":["Sun-facing diffractive sail","H-reversal trajectory","asteroid deflection","Apophis","hodograph method","diffraction angle control","solar radiation pressure","kinetic impact"],"falsifier":"Measure the actual normal and transverse force coefficients of an R-type diffractive sail film in vacuum under the solar flux at 0.3 AU (about 11 times Earth's), insert those measured coefficients into the paper's one-stage Apophis trajectory design at $\\beta=0.70$, and compare the optimized result with a reflective sail; if the impact-velocity gain over the reflective sail is no longer 21% or the mission-time saving is no longer 35%, the central quantitative claim fails.","tokens_in":20795,"feed_emoji":"☀️","tokens_out":9823,"duration_ms":103799,"temperature":0.7,"pith_summary":"The paper is trying to establish that a Sun-facing diffractive sail (SFDS) can carry out the angular-momentum-reversal (H-reversal) trajectory that flips a solar sail into a retrograde orbit, and that this makes it a better kinetic impactor for emergency asteroid deflection than a reflective sail. Because the sail never tilts, it solves the attitude-thrust coupling and solar-radiation-pressure losses that limit reflective sails at the high cone angles needed for transverse acceleration. In an Apophis impact scenario with lightness number $\\beta=0.70$ and a 0.3 AU perihelion, the one-stage diffraction-angle strategy raises the impact velocity by 21% and shortens the mission by 35% relative to a reflective sail, and a two-stage switch of the diffraction angle adds further speed (up to 9 km/s in the abstract scenario, up to 19 km/s at $\\beta=0.62$ in Section V.C). The authors map the feasible parameter space, give trajectory-design algorithms for both strategies, and provide Pareto fronts that trade flight time against impact velocity.","feed_headline":"Sun-facing sail boosts asteroid impact speed by 21%","feed_subtitle":"A diffractive sail also cuts Apophis mission time by 35% versus a reflective sail, simulations show.","key_machinery":"The load-bearing machinery is the ideal diffraction-grating force model for a Sun-facing diffractive sail, expressed in radial and transverse acceleration components $a_r = \\tfrac{\\beta}{2r^2}\\eta_n$ and $a_\\theta = \\tfrac{\\beta}{2r^2}\\eta_p$, with $\\eta_n=1+\\cos\\theta_d$ and $\\eta_p=\\sin\\theta_d$ for the reflection-type configuration; here $\\beta$ is the lightness number $1.53/\\sigma$ and $\\theta_d$ is the diffraction angle of the grating. The hodograph method maps the planar equations of motion into a dimensionless $(v,w)$ velocity space, where the existence of equilibrium points and the position of the Earth-departure state relative to their manifolds partition the space into direct-escape, spiral-inward, and H-reversal regions; this turns the feasibility question into a condition on $(\\beta,\\theta_d)$ and yields the plotted parameter domains. The two-stage strategy switches $\\theta_d$ once, from a milder angle that protects the perihelion constraint to a more negative angle during the solar photonic assist, and its feasibility is mapped in the $(\\theta_{d1},\\chi)$ plane with $\\chi$ the switching-time parameter. The Perihelion-Constrained Phase-Matching Algorithm and the two-stage optimization then select departure epochs and diffraction angles that satisfy terminal position, retrograde-impact, and perihelion constraints.","core_discovery":"The central discovery is that an ideal reflection-type diffractive sail held strictly Sun-facing can perform the whole H-reversal: a steady negative transverse diffractive force drains the sail's heliocentric angular momentum to zero, the sail drops into a retrograde orbit, and the deep solar pass at $r_{p,\\mathrm{target}}=0.3$ AU delivers a strong solar photonic assist that turns solar radiation pressure into orbital energy. The diffraction angle $\\theta_d$ sets the force efficiencies as $\\eta_n=1+\\cos\\theta_d$ and $\\eta_p=\\sin\\theta_d$, so transverse thrust is produced by the sail's microstructured grating rather than by tilting; this removes the $\\cos^3\\alpha$ radial loss and the $\\cos^2\\alpha\\sin\\alpha$ transverse loss of a reflective sail. A constant-$\\theta_d$ (one-stage) trajectory already beats the optimized piecewise reflective-sail H-reversal baseline [36], reaching 102.46 km/s at $\\beta=0.85$ in 0.62 years, and switching once to a more negative $\\theta_d$ near $-90^\\circ$ for the second stage adds more perihelion velocity, bringing terminal impacts to roughly 100$-$106 km/s across the tested lightness numbers.","pith_inferences":["The efficiency gains ride almost entirely on the solar photonic assist near 0.3 AU, so an immediate, cheap test is to measure $\\eta_n$ and $\\eta_p$ of an R-type diffractive film under concentrated sunlight at roughly 11 solar constants; if the ideal $\\eta_p=\\sin\\theta_d$ degrades with temperature, the 21% and 35% margins are the first numbers to shrink.","The same two-stage control logic: hold a safe orbit during the approach, then switch to a high-efficiency diffraction angle at perihelion, is transferable to other low-thrust deflection architectures and to fast Solar System transfers that need a retrograde final leg.","Because the paper works in 2D coplanar motion while Apophis has an inclination of about 3.3 degrees, the natural follow-up is a 3D version of the phase-matching algorithm; out-of-plane forces from the sail would likely shift the optimal launch epochs and could slightly alter the stated margins."],"forward_implications":["At $\\beta=0.70$ and $r_{p,\\mathrm{target}}=0.3$ AU, a one-stage SFDS reaches Apophis with 21% more impact velocity in 35% less time than a reflective sail, directly improving the kinetic energy of an emergency deflection attempt.","The two-stage strategy adds up to 9 km/s in the abstract scenario and up to 19 km/s at $\\beta=0.62$, while cutting transfer time by hundreds of days at low $\\beta$.","An R-type SFDS starts producing H-reversal trajectories at a lower lightness number than a reflective sail ($\\beta=0.43$ versus 0.49 in the unconstrained one-stage case), meaning the maneuver becomes reachable with a less demanding sail film.","The SFDS one-stage strategy outperforms an optimized nine-stage reflective-sail design [36] while requiring only a fixed diffraction angle, so the attitude-control problem is much simpler.","The two-stage optimization yields continuous Pareto curves of flight time versus impact velocity, so a mission designer can choose a $\\beta$ and a point on the curve to fit the urgency of the threat."],"supporting_citations":[{"why":"Supplies the Sun-facing diffractive sail concept and force model that the paper adapts to H-reversal.","marker":"[37]"},{"why":"Establishes the ideal diffraction-grating radiation-pressure model with $\\eta_n$ and $\\eta_p$ efficiency factors.","marker":"[38]"},{"why":"Gives the classification of two-dimensional fixed-attitude solar sail trajectories that the feasibility analysis extends.","marker":"[44]"},{"why":"Provides the hodograph-based feasibility procedure for angular-momentum-reversal trajectories that the paper builds on.","marker":"[45]"},{"why":"Supplies the optimized reflective-sail Apophis H-reversal baseline and the test scenario used for comparison.","marker":"[36]"},{"why":"Introduces the H-reversal trajectory concept for high-speed sailcraft that the paper applies to diffractive sails.","marker":"[29]"},{"why":"Sets the 60 km/s retrograde-impact benchmark that the paper's 100$-$106 km/s results exceed.","marker":"[24]"},{"why":"Supports the engineering feasibility of switching $\\theta_d$ on millisecond timescales with cascaded liquid-crystal polarization gratings for the two-stage strategy.","marker":"[46]"}],"fun_headline_variants":["Diffractive sail hits asteroids 21% faster than reflective sail","Two-stage diffractive sail adds 9 km/s to asteroid impact speed","Sun-facing diffractive sail trims 35% off asteroid mission time","H-reversal diffractive sail: 21% faster impacts, 35% shorter missions"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The argument stands on the assumption that the sail always points at the Sun and that its grating converts sunlight to transverse thrust with the ideal efficiencies $\\eta_n=1+\\cos\\theta_d$ and $\\eta_p=\\sin\\theta_d$, with no optical loss, thermal deformation, or attitude drift; the deep 0.3 AU perihelion pass is exactly where such an idealization is most likely to break down.","fun_headline_variants_meta":{"raw":{"variants":["Diffractive sail hits asteroids 21% faster than reflective sail","Two-stage diffractive sail adds 9 km/s to asteroid impact speed","Sun-facing diffractive sail trims 35% off asteroid mission time","H-reversal diffractive sail: 21% faster impacts, 35% shorter missions"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.001117,"raw_usage":{"total_tokens":4698,"prompt_tokens":1038,"completion_tokens":3660,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":654,"completion_tokens_details":{"reasoning_tokens":3579}},"tokens_in":654,"tokens_out":3660,"duration_ms":32250,"temperature":1.0,"reasoning_tokens":3579,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T21:07:13.725671+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Measure the actual normal and transverse force coefficients of an R-type diffractive sail film in vacuum under the solar flux at 0.3 AU (about 11 times Earth's), insert those measured coefficients into the paper's one-stage Apophis trajectory design at $\\beta=0.70$, and compare the optimized result with a reflective sail; if the impact-velocity gain over the reflective sail is no longer 21% or the mission-time saving is no longer 35%, the central quantitative claim fails.","supporting_citations":[{"cited_title":"Optimal interplanetary trajectories for Sun-facing ideal diffractive sails,","cited_arxiv_id":null,"evidence_quote":"Establishes the ideal diffraction-grating radiation-pressure model with $\\eta_n$ and $\\eta_p$ efficiency factors."},{"cited_title":"Classification of Two-Dimensional Fixed-Sun-Angle Solar Sail Trajectories,","cited_arxiv_id":null,"evidence_quote":"Gives the classification of two-dimensional fixed-attitude solar sail trajectories that the feasibility analysis extends."},{"cited_title":"Feasibility analysis of the angular momentum reversal trajectory via hodograph method for high performance solar sails,","cited_arxiv_id":null,"evidence_quote":"Provides the hodograph-based feasibility procedure for angular-momentum-reversal trajectories that the paper builds on."},{"cited_title":"Utilization of an H-reversal trajectory of a solar sail for asteroid deflection,","cited_arxiv_id":null,"evidence_quote":"Supplies the optimized reflective-sail Apophis H-reversal baseline and the test scenario used for comparison."},{"cited_title":"Sailcraft at high speed by orbital angular momentum reversal,","cited_arxiv_id":null,"evidence_quote":"Introduces the H-reversal trajectory concept for high-speed sailcraft that the paper applies to diffractive sails."},{"cited_title":"Deflection of near-earth asteroids by kinetic energy impacts from retrograde orbits,","cited_arxiv_id":null,"evidence_quote":"Sets the 60 km/s retrograde-impact benchmark that the paper's 100$-$106 km/s results exceed."},{"cited_title":"Dynamic optical beam steering characteristics based on cascaded liquid crystal polarization gratings,","cited_arxiv_id":null,"evidence_quote":"Supports the engineering feasibility of switching $\\theta_d$ on millisecond timescales with cascaded liquid-crystal polarization gratings for the two-stage strategy."}],"review_version":1}