The flyby anomaly is an unexpected energy increase during Earth flybys of satellites. This has been observed as an anomalous shift in the S-Band and X-Band Doppler data which translates to a significant velocity increase of a few mm/s at perigee. So far, no conventional mechanism could be found as being responsible for this effect. Image File history File links No higher resolution available. ... This is a list of some of the unsolved problems in physics. ... Acceleration is the time rate of change of velocity, and at any point on a velocity-time graph, it is given by the slope of the tangent to that point basicly. ... It has been suggested that sling effect be merged into this article or section. ... It has been suggested that sling effect be merged into this article or section. ... The S band ranges from 2. ... The X band (3-cm radar spot-band) of the microwave band of the electromagnetic spectrum roughly ranges from 5. ... A source of waves moving to the left. ... Perigee is the point at which an object in orbit around the Earth makes its closest approach to the Earth. ...

Observations

Gravitational assists, i.e. the technique of changing a spacecraft's heliocentric orbital velocity by means of an exchange of potential and kinetic energy between a planet and a spacecraft, provide an indispensable tool for solar system exploration. Since the success of such a flyby manoeuver depends crucially on the geometry of the trajectory, the position and the velocity of a spacecraft is continuously tracked during its encounter with a planet by the Deep Space Network (DSN). It has been suggested that sling effect be merged into this article or section. ... Timeline of solar system exploration organized by date of launch. ... Mathematically the term trajectory refers to the ordered set of states which are assumed by a dynamical system over time (see e. ... Deep Space Network (DSN) is an international network of radio antennas that supports interplanetary spacecraft missions, and radio and radar astronomy observations for the exploration of the solar system and the universe. ...

The flyby anomaly was first noticed shortly after the Earth flyby of the Galileo spacecraft on 8 December 1990 by a careful inspection of the DSN Doppler data. While it was expected that the Doppler residuals (observed minus computed data) should remain flat, the analysis revealed an unexpected 66 mHz shift which corresponds to a velocity increase of 3.92 mm/s at perigee. An investigation of this effect at the Jet Propulsion Laboratory (JPL), the Goddard Space Flight Center (GSFC) and the University of Texas could not give a satisfying explanation. However, no anomaly was detected after the second Earth flyby of the Galileo spacecraft in December 1992 since any possible velocity increase was masked by atmospheric drag due to the lower altitude of 303 km. Galileo is prepared for mating with the IUS booster Galileo being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ... is the 342nd day of the year (343rd in leap years) in the Gregorian calendar. ... Year 1990 (MCMXC) was a common year starting on Monday (link displays the 1990 Gregorian calendar). ... For the singer/songwriter, see Jon Peter Lewis. ... Aerial view of Goddard Space Flight Center. ... The University of Texas System comprises fifteen educational institutions in Texas, of which nine are general academic universities, and six are health institutions. ... Galileo is prepared for mating with the IUS booster Galileo being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ...

On January 23, 1998 the Near Earth Asteroid Rendezvous (NEAR) spacecraft experienced an anomalous velocity increase of 13.46 mm/s after its Earth encounter. Cassini-Huygens gained ~0.11 mm/s in August 1999 and Rosetta 1.82 mm/s after its Earth flyby in March 2005. January 23 is the 23rd day of the year in the Gregorian calendar. ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... Look up near in Wiktionary, the free dictionary. ... Cassini-Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ... Conceptual drawing of the Rosetta orbiter and Philae lander Rosetta is a European Space Agency-led unmanned space mission launched in 2004 intended to study the comet 67P/Churyumov-Gerasimenko. ...

Two-way X-Band Doppler residuals during Earth flyby of NEAR

Range residuals during Earth flyby of NEAR

See also

• Pioneer anomaly

The Pioneer anomaly or Pioneer effect is the observed deviation from expectations of the trajectories of various unmanned spacecraft visiting the outer solar system, notably Pioneer 10 and Pioneer 11. ...

References

• C. Lämmerzahl, O. Preuss, H. Dittus, Is the physics within the Solar system really understood?, Proceedings of the 359th WE-Heraeus Seminar on "Lasers, Clocks, and Drag-Free: Technologies for Future Exploration in Space and Tests of Gravity" , Preprint: [1], 2006

• J.D. Anderson, J.G. Williams, Long-range tests of the equivalence principle, Class. Quantum Grav., 18, 2447-2456, 2001

• P.G. Antreasian, J.R. Guinn, Investigations into the unexpected delta-v increase during the Earth Gravity Assist of GALILEO and NEAR, paper no. 98-4287 presented at the AIAA/AAS Astrodynamics Specialist Conf. and Exhibition, Boston, 1998

• J.D. Anderson, J.K. Campbell, M.M. Nieto, The Energy Transfer Process in Planetary Flybys, Preprint: [2], 2006