BREAKWELL,JOHN, THE RESTRICTED PROBLEM, AND HALO ORBITS

This Note is based on a presentation made at the special session ''Tri bute to John Breakwell'' of the 42nd IAF Congress (Montreal, 7-11 Octo ber 199 1) recalling the outstanding achievements of J. V. Breakwell i n theoretical Celestial Mechanics. The study of spacecraft oscillating about the Earth-Moon translunar L2 libration point for a communicatio n satellite to service the backside of the moon led to the concept of halo orbits which gained credibility with the launch of ISEE-3 on 12 A ugust 1978 and subsequent insertion of the vehicle into an orbit about the Sun-Earth libration point L1. The investigation was expanded to s earch for complete families of solutions, in particular also near L3. The contribution of the authors (R. W. Farquhar and K. C. Howell) is m entioned.