Extensive kinetic Monte Carlo simulations are presented for ballistic deposition (BD) in (1 + 1) dimensions. Asymptotic scaling is found only for lattice sizes L 2 12 . Such a large system size for the onset of scaling explains the widespread discrepancies of previous reports for exponents of BD in one and likely higher dimensions. The exponents obtained from our simulations, α = 0.499 ± 0.004 and β = 0.336 ± 0.004, are in excellent agreement with the exact values α = 1 2 and β = 1 3 for the one-dimensional Kardar-Parisi-Zhang equation. Our findings enable a more informed exploration of exponents for BD in higher dimensions, accurate estimates of which have proven to be elusive. Fluctuations of growing surfaces are often described by idealized models [1][2][3] wherein the complex interactions between atoms or molecules are replaced by simple transition rules on a lattice that abstract the essence of these interactions. The appeal of such models stems from the fact that their rules can be easily implemented in efficient kinetic Monte Carlo (KMC) algorithms. This enables a comprehensive analysis of their statistical characteristics, which can be compared directly with experiments [4][5][6].A complementary approach is based on postulating a stochastic differential equation. Solutions of such equations typically focus on the asymptotic kinetic roughening regime, where the standard deviation W (L, t) of the surface profile exhibits dynamic scaling [7]:Here, h(x, t) is the surface height at position x and time t, L is the lateral viewing scale, α is the roughness exponent, z is the dynamic exponent, and f is a scaling function. At early times (t ≪ L z ), f (x) ∼ x β and W ∼ t β , where β is the growth exponent and z = α/β. For long times (t ≫ L z ) f → constant, so the saturated roughness W sat ∼ L α . The connection to a lattice model is based on comparing exponents and invoking universality [2].The foregoing paradigm can be justified for many models [2,8], but outstanding issues persist in some cases, most notably, ballistic deposition (BD). Originally formulated as a model for aggregation and sedimentation [9,10], BD is the prototypical model of nonconserved growth, in which the volume of material over the substrate is not equal to that deposited, in this case because of void formation. In classic BD [9, 10] a particle impinges on a randomly chosen lattice site and irreversibly attaches to the first vertical or lateral nearest neighbor encountered. The updating algorithm for the integer heights h i (n) at site i after n depositions isfor i = 1, 2, . . . , L, where max(x, y, z) yields the maximum of the three arguments.The continuum formulation of BD is thought to be the Kardar-Parisi-Zhang (KPZ) equation [11],where u(x, t) is the deviation of the height from its mean at position x and time t on a d-dimensional surface, ν is the surface tension, λ is the "excess velocity," and ξ is a Gaussian noise with mean zero and covarianceAlthough among the first surface growth models to be studied with KMC simulations [7], dis...