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Slava G. Turyshev

Publications and source records attributed to Slava G. Turyshev.

At least 37 records · Page 2Linked to original sources
arXiv2026

Orbital Debris in Earth Orbit: Operations, Stability, Control, and Market Formation

Orbital debris is a nonlinear control problem in a stratified orbital environment, not a static inventory. This paper develops a reduced-order shell-and-size framework that connects collision-rate scaling, fragment-production gain, natural and controlled sinks, and orbital residence time to intervention ranking and procurement design. The formulation identifies three dominant control levers for near-term orbital sustainability: high-confidence disposal and short post-failure residence time for new spacecraft; reduced encounter-plane covariance for the high-risk conjunction tail; and retirement or deflection of the residual hazard stock of long-lived inactive bodies. A source-gain/sink stability margin separates shells that are operationally crowded but dynamically damped from shells that are dynamically amplifying. The analysis distinguishes the traffic-driven workload peak near 500--600 km from the persistence-driven hazard peak near $\sim$850 km, where inactive mass and long lifetime dominate future fragment production. Current public statistics report $\sim$44,870 tracked objects and more than 16,200 tonnes of material in Earth orbit, with model populations far larger below routine-catalog thresholds. The resulting intervention stack is rapid post-mission disposal, targeted covariance improvement for high-risk encounters, selective just-in-time collision avoidance or active removal of high-hazard derelicts. The appropriate procurement metric is not the number of objects removed, but verified reduction in time-integrated environmental hazard: verified disposal, verified reduction in ambiguous high-risk conjunctions, verified reduction in residual hazard stock.

astro-ph.IM↗
arXiv2026

High-Precision Amplitude-Modulated Continuous-Wave Lunar Laser Ranging

Lunar laser ranging (LLR) currently delivers mm-class tests of relativistic gravity and the lunar interior, but further gains are limited by photon-starved pulsed systems, array-induced pulse broadening, and atmospheric variability. This paper develops the metrology and covariance layer for high-power amplitude-modulated continuous-wave (AM-CW) LLR. The optical link budget and kW-class CW architecture are taken from the companion high-power CW LLR analysis; here the focus is on RF-envelope phase observables, multi-tone ambiguity removal, range and range-rate estimators, detector requirements, Doppler derotation, and observation-level covariances. For a GHz-class precision tone, \(c/(4πf_m)\) =2.38567 cm/rad, so 0.10 mm photon-limited range precision requires SNR ~ 240. With detected photon rates appropriate to a 1 kW, 1064 nm transmitter on a 1-2 m class telescope ranging to 10 cm corner-cube retroreflectors, the T ~ 100 s photon-statistical range floor is 0.08-0.14 mm in a generic high-power case, 30-60 um in a dedicated AM-CW case, and <30 um in a photon-rich case. With representative residual atmosphere and instrument allocations, a dedicated station can plausibly reach 0.08 mm absolute range precision under favorable conditions. Range-rate precision below 1 um/s requires several-hundred-second windows, or shorter windows only in photon-rich operation. Differential LLR between nearby lunar reflectors suppresses common-mode station and atmospheric terms, but it cannot suppress independent photon noise. Robust design bands are ~45-90 um for the dedicated AM-CW case and ~35-60 um in photon-rich excellent-seeing operation. The resulting requirements on link SNR, Doppler derotation, detector mode, instrument PSD/Allan stability, oscillator slew, multi-tone nonlinearity, and differential CONOPS are presented.

astro-ph.IM↗
arXiv2026

Orbital Data Centers: Spacecraft Constraints and Economic Viability

Orbital data centers are being evaluated as solar-powered compute constellations and relay-integrated processing platforms. Their feasibility is not set by orbital solar flux alone, but by simultaneous closure of photovoltaic generation, eclipse recharge, radiative heat rejection, sustained space-to-ground communications, utilization, replacement cadence, and delivered compute-years over finite mission life. This paper derives necessary cluster-level competitiveness conditions using delivered information-technology (IT) electrical power $P_{\rm IT}$, deployed mass per delivered IT power $m_{\rm kW}$ in kg/kW, communication intensity $Γ=D_{\rm sg}/E_{\rm IT}$, sustained communication ceiling $Γ_{\max}$, effective utilization $U_{\rm eff}$, and lifetime penalty $Π_{\rm life}$. For a representative $P_{\rm IT}$=1 MW high-sunlight anchor, the base case gives beginning-of-life photovoltaic area $A^{\rm BOL}_{\rm PV}=5.64 \times 10^3 {\rm m}^2$, radiator area $A_{\rm rad}=2.50 \times 10^3 {\rm m^2}$, and 29.4 kg/kW for photovoltaic, storage, and radiator mass; fixed spacecraft mass raises the total to 34-59 kg/kW. At m_kW ~ 40 kg/kW, a terrestrial infrastructure benchmark of 10-40 k\$/kW allows only 250-1000 \$/kg for the combined launch and spacecraft-build cost before space-to-ground communications, operations, utilization, and lifetime terms are included. That allowance is 3.4-13.5 times below the current public Falcon 9 dedicated low-Earth-orbit launch-price benchmark alone, before spacecraft build is included. Space-native preprocessing and communications-integrated edge compute are credible early regimes; terrestrial-user general compute closes only for low Earth-coupled communication intensity, high effective utilization, long delivered lifetime, and very low combined launch-plus-build cost.

physics.gen-ph↗
arXiv2026

Natural Lithopanspermia to Earth: Transport, Shielding, and Survival Limits for Solar-System and Extrasolar Donor Classes

Natural panspermia is a transport-and-establishment hypothesis, not a theory of abiogenesis. The Earth-specific question is whether any nonterrestrial donor remains competitive with terrestrial origin once launch, planetary-system escape, transit, Earth interception, atmospheric entry, terminal loading, and post-delivery establishment are imposed. We formulate this problem as a donor-class dependent Earth-directed transport-survival kernel, supplemented by a minimum protected-depth envelope d_{min}(t_{flight}) and a survival-weighted buried-volume fraction F_{bur} for the low-shock spall population. The resulting hierarchy is strongly ordered under current transport and survival constraints. Hard panspermia is physically credible only on Solar-System scales: early Mars combines demonstrated lithic exchange with Earth, low escape speed, early aqueous habitability, and a rare 10^2-10^4 yr transfer tail, whereas the more common 10^5-10^7 yr martian transfer regime requires lightly shocked meter-class carriers. Beyond the Solar System, low-v_{inf} capture and long-duration survival fail simultaneously; even the Solar birth-cluster channel yields only ~3 x 10^{-5} f_{seed} expected Earth-seeding events, where f_{seed} is the conditional probability that a viable arrival establishes life on Earth. Indigenous terrestrial origin therefore remains the default inference, early Mars is the only quantitatively serious external hard-panspermia alternative, and extrasolar or intergalactic hard panspermia is not competitive for Earth's actual origin history. Soft panspermia is much more plausible as chemical enrichment of early terrestrial abiogenesis.

physics.gen-ph↗
arXiv2026

Science from the In Situ Exploration of the Proxima Centauri System

In the future interstellar exploration at near-relativistic speeds will be possible using beamed energy laser propulsion. With this, spacecraft as small as gm mass picospacecraft become candidates for the exploration of deep space, with a trade space of velocity and mission duration versus mass. Here, we examine the potential science return from interstellar expeditions with Coracle laser-sail picospacecraft swarms and show how even with fast flybys at near relativistic velocities, a picospacecraft swarm could deliver gigapixel resolution of the target exoplanets. Our mission target is the planet Proxima b in the habitable zone (HZ) of the red dwarf Proxima Centauri, the tertiary (and nearest) component of the nearest star system, α Centauri. We explore science returns from such an expedition, both en route to Proxima and at the Proxima system, and conclude that initial small spacecraft expeditions would provide a substantial science return, including the ability to detect surface biology or a technological civilization, should either or both be established on the target planet.

astro-ph.IM↗
arXiv2026

Terraforming Mars: Mass, Forcing, and Industrial Throughput Constraints

Terraforming Mars can be evaluated with a set of system-level constraints linking (i) target pressures & compositions to required atmospheric inventories, (ii) target surface temperatures to the required radiative control, (iii) inventories & climate agents to sustained industrial throughput & power over a build time, (iv) persistence against collapse, escape, geochemical sinks. We use order-of-magnitude scalings to compare endogenous CO2 release, synthetic super-greenhouse gases, CO2-H2 collision-induced absorption, engineered aerosols/nanoparticles, orbital mirrors, regional paraterraforming. We find: (1) human-relevant pressures imply exaton-class inventories, because Mars requires 3.89 x 10^15 kg of atmosphere per mbar of global mean surface pressure; (2) accessible endogenous CO2 is best treated as ~10s of mbar resource, with a 20 mbar case yielding <10 K warming under present insolation; (3) mean surface temperatures of 250-273 K require either effective IR opacity of ~2-4 or direct absorbed-solar forcing of ~100 W/m^2, implying reflector areas of ~10^{13}-10^{14} m^2 together with large deployment, control, durability, replacement burdens; (4) breathable open-surface endpoints are dominated by O2 and N2 inventories and by a minimum oxygenation work exceeding 10^{25} J, implying average build rates of 10^7-10^8 kg/s and average power from multi-100 TW to PW for century-to-millennial build times before inefficiencies and sink filling. We conclude that regional habitability via paraterraforming/covered-area strategies are plausible on near-term industrial scales, whereas no credible open-atmosphere pathway is identified to a Mars permitting pressure-unassisted human exposure or a breathable surface atmosphere without exaton-class volatile supply, multi-century planetary industry, + sustained climate actuation, retention, durability management, replacement against sinks and loss.

astro-ph.EP↗
arXiv2026

Dark Energy After DESI DR2: Observational Status, Reconstructions, and Physical Models

We review late-time cosmic acceleration after DESI Data Release 2 (DR2), emphasizing the interplay between Type Ia supernovae (SNe Ia), anisotropic BAO, CMB calibration, and perturbation-sensitive probes (RSD and weak lensing). DESI DR2 delivers percent-level BAO distance ratios over $0\lesssim z\lesssim2.5$, including a Ly$α$-forest anchor at $z_{\rm eff}=2.33$. In CMB-calibrated combinations, flat $Λ$CDM exhibits a mild parameter mismatch, while allowing evolving dark energy (e.g.\ CPL $w_0$--$w_a$) can improve the fit; the preference is dataset-dependent and is particularly sensitive to redshift-dependent SN calibration/selection residuals at the few$\times10^{-2}$\,mag level. To sharpen likelihood-level interpretation, we provide two diagnostics: (i) an $r_d$-independent BAO-shape observable, $F_{\rm AP}(z)\equiv D_{\rm M}(z)/D_{\rm H}(z)$, constructed directly from published $(D_{\rm M}/r_d,\,D_{\rm H}/r_d)$ with covariance propagation; and (ii) a linear-response map from SN Hubble-diagram systematics $δμ(z)$ to induced biases in $(w_0,w_a)$, yielding an explicit calibration requirement for DESI-era claims of evolving $w(z)$. We synthesize parametric and non-parametric reconstructions of $w(z)$ and $ρ_{\rm DE}(z)$ and map the resulting phenomenology to microphysical dark-energy and modified-gravity models subject to perturbation stability and gravitational-wave propagation constraints.

astro-ph.CO↗
arXiv2026

Production of Jets before Neutron Star Mergers

We demonstrate that magnetospheric interactions between merging neutron stars (NSs) generate dual-jetted current outflows, analogous to the Alfvén wings observed during planetary interactions in the Solar System. Using 3D relativistic MHD simulations, we model the interaction as a conducting sphere moving through a highly magnetized plasma of the companion's magnetosphere. Unusually, the interaction operates in a regime that is relativistic yet sub-Alfvénic. Electromagnetic draping amplifies magnetic fields in a narrow layer near the stellar surface, leading to the generation of electric currents along the local magnetic field. The generation of beamed outflows enhances the instantaneous power of the pulsar-like radio and high-energy emission, produces spin/orbital modulations, and is likely to lead to observable precursor emission preceding the main gravitational wave event.

astro-ph.HE↗
arXiv2026

Phased-Array Laser Power Beaming from Cislunar Space to the Lunar Surface

We present a time-dependent, end-to-end framework for laser power beaming from cislunar orbits to the lunar surface. The model links on-orbit generation (solar arrays and wall-plug to optical), terrain-masked visibility and range, beam propagation with realistic divergence and jitter, and surface conversion with thermal and dust limits, returning delivered daily energy. Baseline loads for early polar activities (habitat survival, mobility, comm/nav, pilot ISRU) set target W h/day and are used consistently in scaling laws and design maps. A near-rectilinear halo orbit (NRHO) to a Shackleton-rim site provides a worked example: for a 2 m-class phased array at 1064 nm the reference geometry yields ~0.6-0.8 kW h/day to a 1m$^2$ receiver (about 28 W averaged over the day). We place this result in context by comparing on the same daily-energy metric to surface photovoltaics (PV) with storage and to compact fission, and by showing how delivered energy scales nearly linearly with transmit power and as $D_{\rm eff}^2$ via encircled-energy capture, with a multiplicative gain from visibility (constellations). The same framework indicates practical regimes already within reach: e.g., a 10 m effective-aperture optical phased array at $P_{\rm tx}=100$ kW delivers ~30-50 kW h/day at polar sites with typical single-orbiter visibility, as quantified by the delivered-energy and sizing maps. Thus, laser beaming is mass-competitive where darkness or permanent shadow forces deep storage for PV, or where distributed and duty-cycled users can amortize a shared transmitter; compact fission retains advantage for continuous multi-kW baseload at fixed sites.

physics.optics↗
arXiv2025

Fundamental Physics in 2025: Status, Decisive Targets, and Path Forward

Fundamental physics today is best defined operationally: it is the program of identifying the microscopic degrees of freedom, symmetries, and dynamical laws that (i) reproduce the Standard Model (SM) of particle physics, General Relativity (GR), and the $Λ$CDM cosmological model in their regimes of validity, and (ii) explain the observed phenomena that these baseline theories do not account for (dark matter, neutrino masses, baryogenesis, dark energy), while resolving conceptual inconsistencies (quantum gravity, naturalness, the cosmological constant problem, the measurement problem in quantum theory, information in black holes) and providing predictive unification. This review first lays out the SM+GR+$Λ$CDM baseline, the best current evidence for its parameters, and the concrete anomalies and missing ingredients. It then surveys the most relevant theoretical directions (effective field theories; amplitude/positivity programs; lattice and many-body methods; symmetry-based model building; cosmological EFTs; quantum information approaches to QFT/gravitation) and the experimental/observational landscape, including ground and space platforms, astronomical messengers, and in-situ tests. Throughout we emphasize: (a) how each observable maps to energy scales and couplings; (b) the dominant statistical and systematic limitations; (c) the sensitivity required for decisive progress. A staged roadmap is given only after the technical review, organized by decision points and cross-checks rather than by specific projects.

gr-qc↗
arXiv2025

Lunar Dust: Formation, Microphysics, and Transport

Lunar dust -- the sub-millimeter fraction of the regolith -- controls the optical, thermophysical, electrical, mechanical, and environmental behavior of the Moon's surface. These properties set the performance envelopes of remote-sensing retrievals, regolith geotechnics, volatile cycles, and exploration systems, while also posing operational and biomedical risks. We synthesize Apollo sample analyses and in-situ observations (Surveyor, Lunokhod, Apollo) with contemporary datasets from the LRO Diviner Lunar Radiometer, the LADEE/LDEX exospheric dust measurements, and Chang'e-4 Lunar Penetrating Radar (LPR). We also incorporate 2024-2025 results: Chandrayaan-3 ChaSTE thermophysics at the Vikram lander's site, SCALPSS plume-surface diagnostics from Intuitive Machines Mission 1 (IM-1), and Negative Ions at the Lunar Surface (NILS) detections of a dayside near-surface H$^{-}$ population on Chang'e-6. The review links (i) production and modification processes to (ii) grain-scale physical/chemical/electrical/optical/mechanical properties, then to (iii) mobilization pathways (meteoroid ejecta, electrostatic hopping, rocket-plume entrainment), and finally to (iv) region-specific design ranges across maria, highlands, pyroclastic units, magnetic swirls, and permanently shadowed regions (PSRs). We quantify temperature-illumination dependence across day/night and PSR-equator regimes through a two-channel $k(T,ρ)$ model and charge-relaxation scaling. We provide closed-form expressions for adhesion-aware lift thresholds and for near-surface (0-3~m) dust transport at apex/hover heights as functions of sheath structure. The result is a design-ready set of relations, figures, and tables that propagate microphysics and composition into engineering parameters for upcoming landed and rover operations.

astro-ph.EP↗
arXiv2025

Information-Thermodynamic Bounds on Planetary Biosphere Productivity and Their Observational Tests

The productivity of a planetary biosphere is limited by how its free-energy budget is partitioned between maintaining a habitable environment, driving metabolism, and processing heritable information. We derive an upper bound on net primary productivity (NPP) from non-equilibrium thermodynamics and information theory, given a planet's usable free-energy flux and a few coarse-grained biological parameters. The bound subtracts an irreducible power cost of heritable information processing -- set by global template-copying rates, copying fidelity, alphabet size, and proofreading work -- from the planetary power budget before converting the remainder into biomass. This yields an ``information-productivity trade-off'': at fixed planetary power, higher copying rates, lower error rates, larger alphabets, or more intensive proofreading all lower the ceiling on biomass production. Using conservative parameter choices, we show that Earth lies well below this ceiling, whereas low-flux environments such as M-dwarf habitable zones and subsurface ocean worlds can be driven into an information-limited regime where only modest combinations of productivity and heritable complexity are attainable. We outline how future exoplanet observations of stellar irradiation, climate, atmospheric disequilibria, and temporal variability could be used to place physics-based upper limits on NPP and compare them with independent productivity estimates.

physics.bio-ph↗
arXiv2025

Direct High-Resolution Imaging of Earth-Like Exoplanets

We have surveyed all conventional methods proposed or conceivable for obtaining resolved images of an Earth-like exoplanet. Generating a 10 x 10 pixel map of a 1 R_E world at 10 pc demands ~0.85 uas angular resolution and photon-collection sufficient for SNR >= 5 per micro-pixel. We derived diffraction-limit and photon-budget requirements for: (1) large single-aperture space telescopes with internal coronagraphs; (2) external starshades; (3) space-based interferometry (nulling and non-nulling); (4) ground-based ELTs with extreme AO; (5) pupil-densified "hypertelescopes"; (6) indirect reconstructions (rotational light-curve inversion, eclipse mapping, intensity interferometry); (7) diffraction occultation by Solar System bodies. Even though these approaches serve their primary goals -- exoplanet discovery and initial coarse characterization -- each remains orders of magnitude away from delivering a spatially resolved image. In every case, technology readiness falls short, and fundamental barriers leave them 2-5 orders of magnitude below the angular-resolution and photon-budget thresholds to map an Earth analog even on decadal timescales. Ultimately, an in-situ platform delivered to <= 0.1 AU of the target could, in principle, overcome both diffraction and photon-starvation limits -- but such a mission far exceeds current propulsion, autonomy, and communications capabilities. By contrast, the Solar Gravitational Lens -- providing on-axis gain of ~1e10 and inherent uas-scale focusing once an imaging spacecraft reaches heliocentric distances beyond >= 550 AU -- is uniquely capable of simultaneously meeting both the resolution and photon-budget requirements. Once mission-specific risks (coronal calibration, focal-plane scanning, deconvolution) are retired, the SGL enables true, resolved surface images and spatially resolved spectroscopy of Earth-like exoplanets in our stellar neighborhood.

astro-ph.IM↗
arXiv2025

High-Precision Relativistic Time Scales for Cislunar Navigation

We present a unified post-Newtonian framework for relativistic timing and coordinate transformations covering six time scales (TCB, TCG, TT, TDB, TCL, TL) and three reference systems (BCRS, GCRS, LCRS). Extending the IAU conventions, we define a Lunicentric Celestial Reference System (LCRS) metric that retains all contributions above a fractional threshold of 5 x 10^{-18} and timing terms above 0.1 ps by expanding the lunar gravity field to spherical-harmonic degree l=9 with Love number variations and including external tidal and inertial multipoles to the octupole. We derive closed-form mappings among TCB, TCG, TT, TCL and TL, yielding proper-to-coordinate time transformations and two-way time-transfer corrections at sub-picosecond accuracy. We evaluate secular rate constants and periodic perturbations arising from kinematic dilation, lunar monopole and multipoles, Earth tides and gravitomagnetic effects for clocks on the lunar surface, in very low and low lunar orbits (vLLO/LLO), in elliptical lunar frozen orbits (ELFOs), at the Earth-Moon L1 point, and in near-rectilinear halo orbits (NRHOs). Our analysis demonstrates that harmonics through l=9 and tides through l=8 are sufficient to achieve 5 x 10^{-18} fractional stability for deep cislunar regimes (e.g., NRHO, Earth-Moon L1), supporting sub-picosecond clock synchronization and centimeter-level navigation; near-surface and vLLO realizations generally require a much higher spherical-harmonic degree, l_max >= 300, to meet the same stability goal. This framework underpins high-precision time and frequency transfer, relativistic geodesy, quantum communication links and fundamental physics experiments beyond low Earth orbit.

gr-qc↗
arXiv2025

High-Precision Lunar Corner-Cube Retroreflectors: A Wave-Optics Perspective

High-precision corner-cube retroreflectors (CCRs) are critical for advanced lunar laser ranging (LLR) because they enable sub-millimeter-scale measurements of the Earth-Moon distance -- a level of precision essential for rigorous tests of relativistic gravitation and for advancing our understanding of lunar geophysics. In this work, we develop a comprehensive two-dimensional Fourier-optics model for single CCRs with apertures ranging from 80-110 mm. Our model incorporates realistic thermal-mechanical wavefront errors, detailed diffraction effects, and velocity aberration offsets. Our analysis reveals a strong coupling between aperture size and aberration angular offset: while larger CCRs deliver high on-axis flux under near-ideal conditions, their narrow diffraction lobes suffer significant flux loss at moderate aberration offsets, thereby favoring smaller apertures with broader main lobes. Furthermore, comparisons between solid fused-silica and hollow silicon-carbide (SiC) CCRs show that hollow designs not only achieve competitive or superior photon return -- particularly at 1064 nm, where phase errors are relatively reduced -- but also offer nearly an order-of-magnitude mass reduction for the same aperture sizes. These results establish a robust quantitative framework for optimizing CCR designs to perform at the sub-millimeter level under realistic lunar conditions and underscore the advantages of precision hollow SiC CCRs for next-generation LLR operations.

physics.optics↗
arXiv2025

Solar System Experiments in the Search for Dark Energy and Dark Matter

We reassess the realistic discovery reach of Solar-System experiments for dark energy (DE) and dark matter (DM), making explicit the bridge from cosmology-level linear responses to local, screened residuals. In scalar-tensor frameworks with a universal conformal coupling $A(ϕ)$ and chameleon/Vainshtein screening, we map cosmological responses $\{μ(z,k),Σ(z,k)\}$ inferred by DESI and \emph{Euclid} to thin-shell or Vainshtein residuals in deep Solar potentials $Φ_N$. We emphasize a two-branch strategy. In a detection-first branch, a verified local anomaly -- an Einstein equivalence principle (EEP) violation, a Shapiro-delay signal with $|γ-1|\sim\mathrm{few}\times 10^{-6}$, an AU-scale Yukawa tail, or a ultralight DM (ULDM) line in clocks/atom interferometers in space (AIS) -- triggers a joint refit of cosmology and Solar-System data under a common microphysical parameterization $\{V(ϕ),A(ϕ)\}$. In a guardrail branch, Solar-System tests enforce constraints (EEP; PPN parameters $γ,β$; and $\dot G/G$) and close unscreened or weakly screened corners indicated by cosmology. We forecast, per conjunction, $|γ-1|\lesssim (2-5)\times 10^{-6}$ (Ka-/X-band or optical Shapiro), $η_{EEP}\sim (1\mbox{--}10)\times 10^{-17}$ (drag-free AIS), $|\dot G/G|\sim(3-5)\times10^{-15}\,\mathrm{yr^{-1}}$ (sub-mm-class LLR), a uniform ~2x tightening of AU-scale Yukawa/DM-density bounds, and $(3-10)\times$ improved ULDM-coupling reach from clocks. For a conformal benchmark, $μ_{ lin,0}=0.10$ implies $χ\simeq \sqrt{μ_{lin,0}/2}$ and a Sun thin shell $ΔR/R\lesssim (1/3χ)\sqrt{|γ-1|/2}=2.4\times 10^{-3}$ at $|γ-1|=5\times 10^{-6}$; Vainshtein screening at 1 AU yields $|γ-1|\lesssim 10^{-11}$, naturally below near-term reach. We recommend a cost-effective guardrail+discovery portfolio with explicit triggers for escalation to dedicated missions.

astro-ph.CO↗
arXiv2025

Lunar Laser Ranging with High-Power CW Lasers

We present a high-power continuous-wave (CW) lunar laser ranging (LLR) technique that has the potential to significantly improve Earth--Moon distance measurements. Using a 1 kW CW laser at 1064 nm and a 1 m-aperture telescope as an example, we develop a detailed link budget and analyze the prevailing noise sources to assess system performance when ranging to next-generation ~10 cm corner-cube retroreflectors (CCRs). Unlike legacy arrays, these smaller CCRs are designed to yield lower intrinsic range errors, yet their reduced reflective area results in lower photon return rates, posing challenges for pulsed LLR systems. The photon-rich CW approach, by providing continuous high-power illumination, overcomes this limitation, reducing shot noise and enabling sustained millimeter-level ranging with a pathway to sub-0.1 mm precision. Furthermore, by alternating measurements between widely separated lunar reflectors, differential LLR mitigates common-mode station errors to achieve tens-of-micrometer precision, limited primarily by uncorrelated atmospheric turbulence. This scalable approach -- integrating high-power CW lasers, narrowband filtering, and rapid atmospheric turbulence averaging -- enables next-generation gravitational tests, precision lunar geodesy, and improved lunar reference frames in support of planetary exploration.

astro-ph.IM↗
arXiv2024

Relativistic Time Transformations Between the Solar System Barycenter, Earth, and Moon

Relativistic corrections are essential for time transformations between geocentric, solar system barycentric, and luni-centric reference systems to account for differences in gravitational potential and relative motion. As the primary reference for Earth-based systems, Terrestrial Time (TT) provides the foundation for precise synchronization across spatial and temporal frameworks. To ensure consistency with TT, Barycentric Dynamical Time (TDB) must exhibit no average rate difference from TT. Although the International Astronomical Union (IAU) has established resolutions for transformations between TT and TDB, extending these frameworks to define a lunar surface time scale (TL) is essential for advancing lunar exploration. This paper derives the (TL - TT) transformation, quantifying a secular drift of 56.0256 us/day and periodic terms, with the largest amplitude of ~0.470 us at the mean anomalistic period. Additionally, the TT-compatible spatial scale and Lorentz contraction of Moon-centered positional coordinates are computed, achieving sub-nanosecond timing precision. These transformations, implemented in JPL ephemeris generation software, provide a robust framework for high-fidelity relativistic models of lunar timekeeping, enabling further refinements and supporting navigation, communication, and scientific operations in cis-lunar space.

astro-ph.EP↗