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P. J. S. Gil

Publications and source records attributed to P. J. S. Gil.

7 recordsLinked to original sources
arXiv2021

Comparison of Four Space Propulsion Methods for Reducing Transfer Times of Crewed Mars Mission

We assess the possibility of reducing the travel time of a crewed mission to Mars by examining four different propulsion methods and keeping the mass at departure under 2500 tonne, for a fixed architecture. We evaluated representative systems of three different state of the art technologies (chemical, nuclear thermal and electric) and one advance technology, the ``Pure Electro-Magnetic Thrust'' (PEMT) concept (proposed by Rubbia). A mission architecture mostly based on the Design Reference Architecture 5.0 is assumed in order to estimate the mass budget, that influences the performance of the propulsion system. Pareto curves of the duration of the mission and time of flight versus mass of mission are drawn. We conclude that the ion engine technology, combined with the classical chemical engine, yields the shortest mission times for this architecture with the lowest mass and that chemical propulsion alone is the best to minimise travel time. The results obtained using the PEMT suggest that it could be a more suitable solution for farther destinations than Mars.

physics.pop-ph↗
arXiv2016

Hyperbolic orbits of Earth flybys and effects of ungravity-inspired conservative potentials

In this work we take a critical look at the available data on the flyby anomaly and on the current limitations of attempts to develop an explanation. We aim to verify how conservative corrections to gravity could affect the hyperbolic trajectories of Earth flybys. We use ungravity-inspired potentials as illustrative examples and show how the resulting orbital simulations differ from the observed anomaly. We also get constraints on the model parameters from the observed flyby velocity shifts. The conclusion is that no kind of conservative potential can be the cause of the flyby anomaly.

gr-qc↗
arXiv2014

Modelling the nongravitational acceleration during Cassini's gravitation experiments

In this paper we present a computation of the thermally generated acceleration of the Cassini probe during its solar conjunction experiment, obtained from a model of the spacecraft. We build a thermal model of the vehicle and perform a Monte Carlo simulation to find a thermal acceleration with a main component of $(3.01 \pm 0.33) \times 10^{-9} {\rm m/s^2}$. This result is in close agreement with the estimates of this effect performed through Doppler data analysis.

gr-qc↗
arXiv2012

Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft

We present an improved method to compute the radiative momentum transfer in the Pioneer 10 & 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set an upper and lower-bound for the thermal acceleration and its evolution with time.

physics.space-ph↗
arXiv2011

Testing the Flyby Anomaly with the GNSS Constellation

We propose the concept of a space mission to probe the so called flyby anomaly, an unexpected velocity change experienced by some deep-space probes using earth gravity assists. The key feature of this proposal is the use of GNSS systems to obtain an increased accuracy in the tracking of the approaching spacecraft, mainly near the perigee. Two low-cost options are also discussed to further test this anomaly: an add-on to an existing spacecraft and a dedicated mission.

physics.space-ph↗
arXiv2011

Probing the Flyby Anomaly with the Galileo Constellation

In the last few years, the so-called flyby anomaly has been widely discussed, but remains still an illusive topic. This is due to the harsh conditions experienced during an Earth flyby as well as due to the limited data available. In this work, we assess the possibility of confirming and characterizing this anomaly by resorting to the scientific capabilities of the future Galileo constellation.

gr-qc↗