Kinematics effects of atmospheric friction in spacecraft flybys

Acedo, L.

doi:10.1016/j.asr.2017.01.008

Cited by 6 publications

(5 citation statements)

References 33 publications

(60 reference statements)

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“…On the other hand, there is, at least, one flyby in the series we are considering in which the effect of atmospheric friction cannot be neglected. For the second Galileo flyby of the Earth in December 8th, 1992 the minimum altitude was 303 km and, in this case, a total decrease of the final asymptotic velocity of −4.6 mm/s (from the observed −8 mm/s) is attributed only to friction [7,3]. This effect is to be carefully incorporated into the orbital model for this flyby in order to disclose any remaining anomalous acceleration.…”

Section: Atmospheric Frictionmentioning

confidence: 95%

“…We will show that for altitudes over 500 km the deceleration is negligible because the density of the thermosphere at those altitudes is very low. In particular, for the NEAR flyby the impact of this effect on the final outgoing velocity has been evaluated in the range of a hundredth of mm/s [3]. The drag force due to the atmospheric friction is estimated by the usual expression [49]:…”

Section: Atmospheric Frictionmentioning

confidence: 99%

“…In this case, the altitude at perigee was attained inside the thermosphere and atmospheric friction must be taken into account. However, it has been estimated that only −3.4 mm/s should correspond to this atmospheric friction effect [7,3]. Other flybys performed by the NEAR, Cassini and Rosetta spacecraft have also exhibited these flyby anomalies.…”

Section: Introductionmentioning

confidence: 99%

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Anomalous accelerations in spacecraft flybys of the Earth

Acedo

2017

Astrophys Space Sci

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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 with the initial velocity that cannot be attributed to conventional effects. To elucidate its origin, we have developed an orbital program for analyzing the trajectory of the spacecraft in the vicinity of the perigee, including both the Sun and the Moon's tidal perturbations and the geopotential zonal, tesseral and sectorial harmonics provided by the EGM96 model. The magnitude and direction of the anomalous acceleration acting upon the spacecraft can be estimated from the orbital determination program by comparing with the trajectories fitted to telemetry data as provided by the mission teams. This acceleration amounts to a fraction of a mm/s 2 and decays very fast with altitude. The possibility of some new physics of gravity in the altitude range for spacecraft flybys is discussed.

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Section: Atmospheric Frictionmentioning

confidence: 95%

Section: Atmospheric Frictionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Anomalous accelerations in spacecraft flybys of the Earth

Acedo

2017

Astrophys Space Sci

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“…To address what are the consequences of the space weather, in terms of solar and geomagnetic activities, on the orbital capacity, the static exponential density model can be replaced by the following density model [19]:…”

Section: Optimal Solution and Stability Analysismentioning

confidence: 99%

The Capacity of Low Earth Orbit Computed using Source-sink Modeling

D’Ambrosio¹,

Lifson²,

Linares³

2022

Preprint

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The increasing number of Anthropogenic Space Objects (ASOs) in Low Earth Orbit (LEO) poses a threat to the safety and sustainability of the space environment. Multiple companies are planning to launch large constellations of hundreds or thousands of satellites in the near future, increasing congestion in LEO and the risk of collisions and debris generation. This paper employs a new multi-shell multi-species evolutionary source-sink model, called MOCAT-3, to estimate LEO orbital capacity. In particular, a new definition of orbital capacity based on the stable equilibrium points of the system is provided. Moreover, an optimization approach is used to compute the maximum orbital capacity of the low region of LEO (200-900 km of altitude), considering the equilibrium solutions and the failure rate of satellites as a constraint. Hence, an estimate for the maximum number of satellites that it is possible to fit in LEO, considering the stability of the space environment, is obtained. As a result, considering 7% of failure rate, the maximum orbital capacity of LEO is estimated to be about 12.6 million satellites. Compatibility of future traffic launch, especially in terms of satellite constellations, is also analyzed and a strategy to accommodate for future traffic needs is proposed.

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“…Ocean tides and a coupling of the spacecraft to the tesseral harmonic terms in the geopotential model have also recently been studied [2]. Atmospheric friction can also be dismissed except for flybys at altitudes of 300 km or lower [4]. The same can be said of the corrections corresponding to General Relativity [28,26], thermal effects [43] or other [14].…”

Section: Introductionmentioning

confidence: 99%

A possible flyby anomaly for Juno at Jupiter

Acedo

Piqueras

Moraño

2018

Advances in Space Research

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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 context of the most accurate orbital models including all known effects from classical dynamics and general relativity. Of particular interest for its puzzling nature, and the lack of any accepted explanation for the moment, is the flyby anomaly discovered in some spacecraft flybys of the Earth over the course of twenty years. This anomaly manifest itself as the impossibility of matching the pre and post-encounter Doppler tracking and ranging data within a single orbit but, on the contrary, a difference of a few mm/s in the asymptotic velocities is required to perform the fitting.Nevertheless, no dedicated missions have been carried out to elucidate the origin of this phenomenon with the objective either of revising our understanding of gravity or to improve the accuracy of spacecraft Doppler tracking by revealing a conventional origin.With the occasion of the Juno mission arrival at Jupiter and the close flybys of this planet, that are currently been performed, we have developed an orbital model suited to the time window close to the * E-mail: luiacrod@imm.upv.es 1 perijove. This model shows that an anomalous acceleration of a few mm/s 2 is also present in this case. The chance for overlooked conventional or possible unconventional explanations is discussed.

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Kinematics effects of atmospheric friction in spacecraft flybys

Cited by 6 publications

References 33 publications

Anomalous accelerations in spacecraft flybys of the Earth

Anomalous accelerations in spacecraft flybys of the Earth

The Capacity of Low Earth Orbit Computed using Source-sink Modeling

A possible flyby anomaly for Juno at Jupiter

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