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The flyby anomaly is a persistent riddle in astrodynamics. Orbital analysis in several flybys of the Earth since the Galileo spacecraft flyby of the Earth in 1990 have shown that the asymptotic post-encounter velocity exhibits a difference…
An empirical formula recently appeared in the literature to explain the observed anomalies of about $\Delta\dot\rho\approx 1-10$ mm s$^{-1}$ in the geocentric range-rates $\dot\rho$ of the Galileo, NEAR and Rosetta spacecraft at some of…
All anomalous velocity increases until now observed during the Earth flybys of the spacecrafts Galileo, NEAR, Rosetta, Cassini and Messenger have been correctly calculated by computer simulation using an asymmetric field term in addition to…
In 2008 a group of NASA scientists reported an anomalous change in the speed of six spacecraft flybys of the Earth. The reported speed change for the NEAR spacecraft flyby is 13.46+-0.01 mm/s. It is known that general relativity theory…
The so-called flyby anomaly is a yet unexplainable velocity jump measured at several Earth flybys of spacecraft. Known physical effects could be excluded as source of this anomaly. In order to model a possible new physical effect, empirical…
In the last decades there have been an increasing interest in improving the accuracy of spacecraft navigation and trajectory data. In the course of this plan some anomalies have been found that cannot, in principle, be explained in the…
The flyby anomalies are unexplained velocity increases of 3.9, 13.5, 0.1 and 1.8 mm/s observed near closest approach during the Earth flybys of the Galileo, NEAR, Cassini and Rosetta spacecraft. Here, these flybys are modelled using a…
Close planetary flybys are frequently employed as a technique to place spacecraft on extreme solar system trajectories that would otherwise require much larger booster vehicles or may not even be feasible when relying solely on chemical…
We report on dust measurements obtained during the seventh orbit of the Galileo spacecraft about Jupiter. %which had a close flyby at Ganymede. The most prominent features observed are highly time variable dust streams recorded throughout…
The Gravity Assisted Maneuver has been applied in lots of space missions, to change the spacecraft heliocentric velocity vector and the geometry of the orbit, after the close approach to a celestial body, saving propellant consumption. It…
In March 2008 anomalous behavior in spacecraft flybys of Earth was reported in Physical Review Letters, Volume 100, Issue 9, March 7, 2008, in an article entitled "Anomalous Orbital-Energy Changes Observed during Spacecraft Flybys of…
We examine the mechanisms by which atmosphere can be eroded by giant impacts onto Earth-like planets with thin atmospheres, using 3D smoothed particle hydrodynamics simulations with sufficient resolution to directly model the fate of…
Extragalactic jets in active galactic nuclei (AGN) are divided into two morphological types, namely Fanaroff-Riley I (FRI) and Fanaroff-Riley II (FRII). The former show decollimated structure at the kiloparsec scales and are thought to be…
Aerocapture uses atmospheric drag to decelerate spacecraft and achieve orbit insertion. One of the significant risks associated with aerocapture is the uncertainty in the atmospheric density, particularly for outer planets. The paper…
The so-called flyby anomaly has encouraged several authors to analyze in detail the minor perturbative contributions to the trajectory of spacecraft performing a flyby manoeuvre. This anomaly consist of an unexplained increase or decrease…
In the last two decades an anomalous variation in the asymptotic velocity of spacecraft performing a flyby manoeuvre around Earth has been discovered through careful Doppler tracking and orbital analysis. No viable hypothesis for a…
This paper investigates the influence of nonlinear dissipative forces, specifically Gravitational Friction (GF), on the precession of celestial bodies within the framework of general relativity. We derive a modified line element by…
Data of six flybys, those of Galileo I, Galileo II, NEAR, Cassini, Rosetta and Messenger were reported by Anderson et al \citep{Anderson}. Four of them: Galileo I, NEAR, Rosetta and Messenger gain Newtonian energy during the flyby transfer,…
A possibility of geophysical measurements using the large scale laser interferometrical gravitational wave antenna is discussed. An interferometer with suspended mirrors can be used as a gradiometer measuring variations of an angle between…
A two-dimensional, time-dependent numerical model is used to calculate the modulation of cosmic rays in the heliosphere. Computations are compared to spacecraft observations in the inner and outer heliosphere. It is shown that the model…