Five years in the making, the National Astronomy and Ionosphere Center (NAIC) and Motorola, Inc. signed a memorandum of understanding in March that extends some protection from interference to radio astronomers who use the Arecibo Radio Telescope in Puerto Rico.

Motorola, which operates the IRIDIUM commercial communications satellite system, has agreed to guarantee 8 hours of radio observing time each day—from 10:00 p.m. to 6:00 a.m. U.S. Eastern Standard Time (6:00–11:00 UT)—that is free of potential signal interference from its satellites. With 66 IRIDIUM satellites scheduled to be operational in low-Earth orbit this fall, the agreement had taken on some urgency.