The project EROLD (Earth Rotation from Lunar Distances) was conceived in 1974, in the COSPAR framework, with the goal of demonstrating that the lunar distances technique might be an efficient candidate in a new-generation service for the determination of Earth orientation.

Two years later, it was decided that the computations of the observational residuals and partial derivatives, as well as the analyses themselves, would be done at C.E.R.G.A. on a regular basis, for all the participating stations. Indeed, it was recognized to be important that all the observations be reduced in an homogeneous process. The target chosen for this program was that of Apollo XV which is the easiest to observe. Unfortunately, the operations could not start quickly due to a lack of observations and each station was encouraged to press the completion of the equipment, but many problems slowed the integration of these stations. Still now, only McDonald Observatory transmits observations regularly, and Orroral is operating, but with scattered results; presently this latter station is in course of modifications for improvement of accuracy.