Two satellites move in the same circular orbit of radius $r$ around a star, with speed $v$ and period $T$, traveling in the same direction. Initially the second satellite is one quarter-orbit ahead of the first. The first satellite briefly fires its retrorockets, instantaneously reducing its speed and dropping into an elliptical orbit. After the first satellite completes exactly one full revolution on this new ellipse, the two satellites meet. To what speed must the first satellite reduce, approximately?