  The quasi-satellite (QS) phenomenon makes two celestial bodies to fly near
each other (Mikkola et al. 2006) and that effect can be used also to make
artificial satellites move in tandem. We consider formation flight of two or
three satellites in low eccentricity near Earth orbits. With the help of weak
ion thrusters it is possible to accomplish tandem flight. With ion thrusters it
is also possible to mimic many kinds of mutual force laws between the
satellites. We found that both a constant repulsive force or an attractive
force that decreases with the distance are able to preserve the formation in
which the eccentricities cause the actual relative motion and the weak
thrusters keep the mean longitude difference small. Initial values are
important for the formation flight but very exact adjustment of orbital
elements is not important. Simplicity is one of our goals in this study and
this result is achieved at least in the way that, when constant force thrusters
are used, the satellites only need to detect the directions of the other ones
to fly in tandem. A repulsive acceleration of the order of 10^-6 times the
Earth attraction, is enough to effectively eliminate the disruptive effects of
all the perturbations at least for a timescale of years.
