abstract

We present new spectroscopic measurements for two dust analogue samples: walnut charcoal and willow charcoal. These measurements were performed in our laboratory using a Cary 5000 spectrometer equipped with an integrating sphere. This measurement setup enabled the measurement of hemispherical albedo as a function of wavelength in the range from 200 to 2500 nm. The obtained hemispherical albedo values ranged from 0.10 to 10.89%. Based on the obtained spectral profile measurements, the Bond albedo and geometric albedo values were calculated for selected possible analogues of refractory material present on cometary surfaces. The obtained mean Bond albedo value was 0.49%, while the mean geometric albedo value was 1.90%. These results were compared with macromolecular carbonaceous material present in cometary dust from comets. The obtained results were compared with measurements made by Rosetta/COSIMA, which showed that the cometary dust is dominated by macromolecular carbonaceous material, which is responsible for the very low albedo of comet 67P/Churyumov–Gerasimenko.

abstract

We investigate the feasibility of redirecting trans-Neptunian objects (TNOs) from the Kuiper Belt to Mars using sustained low-thrust propulsion combined with a single Neptune gravity assist. Numerical trajectory optimisation with global derivative-free solvers shows that carefully phased low-thrust control can reduce the required \(\Delta V\) to approximately 2.5–3.2 km s\(^{-1}\) for transfer times of several centuries. For the higher-eccentricity test case, a well-timed Neptune flyby further lowers the propulsive cost, whereas for the lower-eccentricity case, it yields only marginal savings at the expense of a longer transfer time. We illustrate the sensitivity to the initial semi-major axis, eccentricity, and inclination, describe the trade-off between pre- and post-assist control effort, and discuss structural and operational limitations. The results suggest dynamical accessibility for inward volatile delivery from the outer Solar System within an idealized model.