DOI: 10.5281/zenodo.17009951
title: Lunar Trailblazer Attitude Estimation Data for Robinson et al.

description: The files included in this dataset include the ephemerides, light curve data, attitude estimation results, and material sensitivity results for Robinson et al.:



@article{robinson2025ltb,

title = {Material Property Sensitivity of Light Curve Attitude Estimation for the Lunar Trailblazer},

journal = {Earth and Space Science},

note = {Submitting for the Lunar Trailblazer special issue},

year = {2025},

volume = {},

number = {},

author = {Liam Robinson and Amanda Steckel and Carolin Frueh and Bethany Ehlmann}

}

 

The data is broken up into:





ephem.parquet: Ephemeris data for LTB from the JPL Horizons web service with columns:



utc: The UTC datetime of each data point

r_j2000_km: The position vector of LTB in the J2000 coordinate system in kilometers



df_in_{gemini49,lowell310}.parquet: Light curve data from the Gemini and Lowell observatories with columns:



dates: the UTC datetime of each photometric measurement

ovi: The direction of the observer in inertial (J2000) space from the center of mass of LTB, unit vector

svi: The direction of the Sun in inertial (J2000) space from the center of mass of LTB, unit vector

irrad: The photometric brightness of LTB, reduced from the raw FITS files and rescaled [dimensionless, proportional to the observed analog-to-digital unit (ADU) counts]

irrad_sigma: The standard deviation of the irrad column derived from the image background and the Poisson statistics of the photon counting process [same dimensions as irrad]

epsecs: Seconds after the first observation in the current light curve



{1,2}{L,G}.parquet: Local minimum attitude state estimates produced by the inversion algorithm described in the work for each of the results cases (1L, 2L, 1G, 2G) described in the work, with columns:



index: The sampling index of the initial condition

fun: The objective function value at the converged minimum

xk: The converged state vector value

x0: The initial state vector value before optimization

message: The output message of the BFGS solver

iterations: The number of iterations of BFGS required to reach convergence

feval: The number of objective function evaluations required to reach convergence

geval: The number of gradient evaluations required to reach convergence

gradient: The gradient vector at xk

hessian_inverse: The BFGS approximation of the inverse Hessian matrix at xk

lcs: The predicted light curve signal produced by the state xk at each of the observation times

epsecs: The number of seconds past the initial observation corresponding to each entry of lcs

obj_file_path: The shape file path used for the inversion case

substeps: The number of propagation substeps used to simulate each light curve observation

self_shadowing: Whether self-shadowing effects are accounted for, always True for this work

vary_global_mats: Irrelevant for this work, always False

vary_itensor: Irrelevant for this work, always False

cache_size: The size of the azimuth and elevation dimensions of the shadow cache

cs_scale: Irrelevant for this work, always 0

n_scale: Irrelevant for this work, always 0

i_scale: Irrelevant for this work, always 0

iratios: Inertia ratios of the spacecraft

finite_difference_step_size: Step size to compute gradients within BFGS

mats: Materials assigned to each face of the object

cds: Coefficients of diffuse reflectivity of each face of the object

css: Coefficients of specular reflectivity of each face of the object

ns: Third BRDF parameter (e.g., surface roughness or specular exponent)



2{L,G}_ms.parquet: The sensitivity information of the top 200 solutions to the 2L and 2G results cases to deviations in the spacecraft's surface reflectivity properties.



sol_ind: Row index of the solution in the corresponding 2{L,G}.parquet file

mat: The name of the material

ang_{cd,cs,n}: The angular deviation in orientation expected for a 10% deviation in the coefficients of diffuse (cd) or specular (cs) reflectivity, or the surface roughness (n).

period_mins_nom: The nominal spin rate of this solution in minutes

period_mins{cd,cs,n}: The perturbed spin rate of this solution expected for a 10% deviation in the coefficients of diffuse (cd) or specular (cs) reflectivity, or the surface roughness (n).