by Douglas Messier
SpaceX is set to launch two spacecraft next week that will demonstration technologies for providing fast global broadband services through a constellation of 12,000 satellites.
Microsat-2a and Microsat-2b spacecraft will hitch a ride aboard a Falcon 9 booster whose primary payload is the Paz synthetic aperture radar satellite. The launch has been rescheduled for Wednesday, Feb. 21 at 6:17 a.m. PST ( 9:17 a.m. EST; 1417 GMT) from Vandenberg Air Force Base in California.
“Both of these satellites will be deployed in one mission aboard a SpaceX Falcon 9 launch vehicle into an orbital plane of 514 km circular at 97.44 degrees inclination,” the company said in an application to the Federal Communications Commission (FCC).
“After insertion, the satellite orbits will be raised to the desired mission altitude of 1125 km circular,” the application added. “The designed lifetime of each satellite is 20 months. If this lifetime is exceeded, SpaceX plans to continue operation until such time as the primary mission goals can no longer be met, at which point the spacecraft will be deorbited.”
The microsats each measure 1.1 m x 0.7 m x 0.7 m and weigh approximately 400 kg. They carry a flight computer, power system components, attitude determination and control components, propulsion components, GPS receiver, and broadband, telemetry, and command receivers and transmitters.
“The attitude of each spacecraft is 3-axis stabilized, and is dynamically controlled over each orbit to maintain attitude position for two pointing modes of operation: broadband antenna (antennas to nadir for testing) and solar array (solar arrays facing sun for charging),” the application stated. “Power is provided by solar panels designed to deliver sufficient power at the predicted end of spacecraft life to not impair any test objectives. The Thermal Control System ensures that components are kept within operational temperature ranges.”
Elon Musk’s company has applications for two constellations of satellites before the FCC for its Starlink broadband services. One application is for 4,425 satellites plus orbital spares that would operate in the Ku and Ka bands. The company will launch satellites for this constellation this week.
The second application is for the operation of a constellation of 7,518 satellites to provide communications services in the little used V band. Those satellites would orbit at lower altitudes.
“When combined into a single, coordinated system, these ‘LEO’ and ‘VLEO’ constellations will enable SpaceX to provide robust broadband services on a full and continuous global basis,” the company said in its application for the larger constellation.
SpaceX Vice President Patricia Cooper outlined the company’s plans before the Senate Commerce, Science and Technology Committee last May.
“To implement the system, SpaceX will utilize the availability of significantly more powerful computing and software capabilities, which will enable SpaceX to allocate broadband resources in real time, placing capacity where it is most needed and directing energy away from areas where it might cause interference to other systems, either in space or on the ground,” Cooper said in her prepared testimony. [Prepared Statement — PDF]
“Because the satellites will beam directly to gateways or user terminals, the infrastructure needed on the ground—particularly in rural or remote areas—is substantially reduced, essentially addressing the “last mile” challenge and helping to close the digital divide,” she added. “In other words, the common challenges associated with siting, digging trenches, laying fiber, and dealing with property rights are materially alleviated through a space-based broadband network.”
SpaceX plans begin launching operational satellites beginning in 2019, with all 4,425 spacecraft in the first constellation being in orbit by 2024.
“For the end consumer, SpaceX user terminals—essentially, a relatively small flat panel, roughly the size of a laptop—will use similar phased array technologies to allow for highly directive, steered antenna beams that track the system’s low-Earth orbit satellites,” Cooper said. “In space, the satellites will communicate with each other using optical inter-satellite links, in effect creating a “mesh network” flying overhead that will enable seamless network management and continuity of service.
“In the future, these satellites would provide additional broadband capacity to the SpaceX system and further reduce latency where populations are heavily concentrated,” Cooper added.
There is an international race to provide global broadband satellite services. FCC has approved access to the U.S. market for satellite systems planned by OneWeb, Space Norway and Telesat.
In a statement issued last week, FCC Chairman Ajit Pai — who led the effort to end net neutrality that critics say could lead service providers to charge more for less access to the Internet — invoked the need to provide broadband services to all in backing SpaceX’s application for the smaller constellation.
“To bridge America’s digital divide, we’ll have to use innovative technologies,” he said. “SpaceX’s application—along with those of other satellite companies seeking licenses or access to the U.S. market for non-geostationary satellite orbit systems—involves one such innovation. Satellite technology can help reach Americans who live in rural or hard-to-serve places where fiber optic cables and cell towers do not reach. And it can offer more competition where terrestrial Internet access is already available.
“Following careful review of this application by our International Bureau’s excellent satellite engineering experts, I have asked my colleagues to join me in supporting this application and moving to unleash the power of satellite constellations to provide high-speed Internet to rural Americans,” Pai added. “If adopted, it would be the first approval given to an American-based company to provide broadband services using a new generation of low-Earth orbit satellite technologies.”