Boeing 601
The Boeing 601 is a retired communications satellite bus designed in 1985 and introduced in 1987 by Hughes Space and Communications Company. The series was extremely popular in the 1990s, with more than 84 purchased by customers globally. The more advanced 601HP derivative was introduced in 1995. Hughes, and the 601 platforms, were acquired by Boeing in 2000.
The last commercial 601 satellite was ordered in 2001 and launched in 2004. The NASA Space Communications and Navigation Program Office in December 2007 selected the BSS-601HP for its third generation TDRS spacecraft, adding the two 15-foot diameter steerable antennas. The TDRS-M satellite, launched on August 18, 2017, became the last 601 satellite to reach orbit.
Background
The Boeing-601 model was Hughes’ first major design and development for a communications satellite with three-axis, or body stabilization. All previous Hughes satellite models had been cylindrical spacecraft that were spin-stabilized at 50 revolutions per minute.Design of the Boeing-601 began in 1985, with full-scale development following two years later. The new satellite's first official public presentation took place at the Telecom 87 conference in Geneva, Switzerland.
Variants
; Boeing-601HP: A high-power version of the standard model Boeing-601, it supports up to 60 transponders and 10,000 watts, making it twice as powerful as the standard 601. Innovations in gallium arsenide solar cells, battery technology, and xenon ion propulsion systems facilitated this upgrade. The 601HP made its debut in 1995, with upgrades in 2000 to address design and component failures.; Ultra High Frequency Follow On : The U.S. Navy began replacing and upgrading its ultra-high frequency satellite communications network during the 1990s with a constellation of customized HS-601 satellites known as the UFO series. Eleven UFO satellites were launched between 1993 and 2003. The UHF Follow-On constellation replaced the Fleet Satellite Communications and the Hughes-built Leasat spacecraft.
; Third generation GOES satellites: The Geostationary Operational Environmental Satellite system, operated by NOAA, selected the standard Boeing 601 bus for its third generation weather satellites, GOES-13, GOES-14, and GOES-15. This series featured a sun-pointed extreme ultraviolet sensor, a Solar X-Ray Imager, and space environment monitoring instruments for their space weather role.
; Tracking and Data Relay Satellite : The second generation satellites used the standard 601 bus, while the follow-on third generation satellites use the 601HP bus, after design changes addressing satellite failures in 1990s. The TDRS version features two 15-foot-diameter steerable graphite composite mesh antennas. These antennas are partially curled-up like a taco shell to fit within the Atlas/Centaur payload fairing.