  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 determined cross-track post-fit residuals of MGS, built up by
neglecting just the gravitomagnetic force in the dynamical force models and
without fitting any empirical cross-track acceleration which could remove the
relativistic signal, amount to 1.6 m, on average, over a 5-years time interval
spanning from 10 February 2000 to 14 January 2005. The discrepancy with the
predictions of general relativity is 6%.
