According to general relativity, the gravitomagnetic Lense-Thirring force of Mars would secularly shift the orbital plane of the Mars Global Surveyor (MGS) spacecraft by an amount of 1.5 m, on average, in the cross-track direction over 5 years. The determi

6

2

n

Ju

1

2

1

v2

9

6

6

/

c

q

-

r

:gv

i

X

r

aEvidenceofthegravitomagnetic eldofMarsLorenzoIorioVialeUnita`diItalia68,70125Bari,Italytel./fax00390805443144e-mail:lorenzo.iorio@libero.itAbstractAccordingtogeneralrelativity,thegravitomagneticLense-ThirringforceofMarswouldsecularlyshifttheorbitalplaneoftheMarsGlobalSurveyor(MGS)spacecraftbyanamountof1.5m,onaverage,inthecross-trackdirectionover5years.Thedeterminedcross-trackpost- tresidualsofMGS,builtupbyneglectingjustthegravitomagneticforceinthedynamicalforcemodelsandwithout ttinganyempiri-calcross-trackaccelerationwhichcouldremovetherelativisticsignal,amountto1.6m,onaverage,overa5-yearstimeintervalspanningfrom10February2000to14January2005.Thediscrepancywiththepredictionsofgeneralrelativityis6%.Keywords:generalrelativity;Lense-Thirringe ect;Marsgravity eld;MarsGlobalSurveyor;out-of-planepartoftheorbit1IntroductionInthiscommunicationweproposetoexplaincertainmeasuredfeaturesof

thepathoftheMartianorbiterMarsGlobalSurveyor(MGS)(Konoplivetal.2006),whoseorbitalparametersarequotedinTable1,withtheactionofthegeneralrelativisticgravitomagneticforceonthespacecraft.Ifcon rmedbysubsequent,dedicatedanalysesitwouldbe,ingeneral,the rsttestofgeneralrelativityinthegravitational eldofaSolarSystembodyotherthantheSunandtheEarthand,inparticular,the rstindependenttestoftheLense-Thirringe ectwithrespecttothoseconductedsofarwiththeLAGEOSsatellitesintheEarth’sgravitational eld(IorioandMorea2004,CiufoliniandPavlis2004,Iorio2006).

1