The Celestri Multimedia LEO System was a planned Low Earth orbit (LEO) satellite constellation, which was intended to offer global, low-latency broadband Internet services via Ka-band radio links.^[1] It was planned by Motorola circa 1997-1998 as one of the earliest "Internet in the sky" constellations, and as a successor to the company's Iridium satellite constellation, but never built or launched.

The Celestri constellation was envisioned to consist of 63 operational satellites in 7 orbital planes, inclined at 48° with respect to the Equator, plus up to 7 in-orbit spares.^[1] Satellites in each plane would follow circular orbits at an altitude of 1400 kilometers.^[1] Each satellite was envisioned to contain all hardware and software needed to route traffic throughout the network, including Earth-to-space in the 28.6-29.1 GHz and 29.5-30.0 GHz bands, space-to Earth in the 18.8-19.3 GHz and 19.7-20.2 GHz bands, and space-to-space connections via optical inter-satellite links.^[1] Satellites were expected to employ phased array antennas supporting 432 uplink beams and 260 downlink beams per satellite,^[2] provided by Raytheon,^[3] to communicate with Celestri ground stations, which would have equivalent antenna aperture sizes from 0.3 to 1 meter to support communications at rates from 2.048 to 155.52 Mbps.

Celestri's anticipated cost was $12.9 billion.^[4] In May 1998, Motorola announced that it was dropping its plans for the Celestri system, and instead would invest $750 million in the rival Teledesic constellation.^[5] The combined project was ultimately abandoned in 2003.^[6]