Orbiting 250 miles overhead and circling the Earth every 90 minutes, the International Space Station (ISS) serves as an outpost for exploration and scientific discovery. For 15 years, humans have been living continuously aboard the space station and making research breakthroughs not possible on Earth. A truly global endeavor, more than 200 people from 15 countries have visited the unique microgravity laboratory that has hosted more than 1,700 research investigations from researchers in more than 83 countries.
As with satellites and other technology operating in space, the ISS relies on radio spectrum for communications and mission critical activities. This includes communicating with mission controllers on Earth, communicating with spacecraft transporting crew and cargo to and from the ISS, performing experiments aboard the ISS, and determining the exact position of the space station. But with the proliferation of so many new wireless technologies from tablets to smart watches, all users of spectrum are now operating in a much more congested spectrum environment, driving the need for new ways to use the airwaves much more efficiently.
The U.S. Commerce Department’s National Telecommunications and Information Administration (NTIA), manager of spectrum use for federal agencies, has been working to make more spectrum available for commercial wireless uses while also ensuring federal agencies have the airwaves they need to perform vital missions for the American people. To meet this challenge, NTIA has promoted research into new technologies to help agencies and others use spectrum more efficiently, including through the expanded use of spectrum sharing.
NASA shares this goal and has developed the Space Communications and Navigation (SCaN) Testbed, which has been installed on the ISS to research new ways to use radio spectrum more efficiently. This system, developed under the Communications, Navigation, and Networking Configurable Testbed (CoNNeCT) project at NASA’s John Glenn Research Center in Cleveland, is being used to test the capabilities of software defined radios (SDR).
Unlike a traditional radio with a fixed set of communication protocols built into its hardware, an SDR has software incorporated into the device that can be reconfigured in almost any way and at any time simply with an update to its programming. This allows the same radio to adjust it modulation, coding and data rate on the fly to adapt to changing radio channel characteristics within the allocated spectrum required for a particular type of operation, such as transmitting video, data, or voice communications.
NASA is partnering with other government agencies, industry, and academia to use the SCaN Testbed as a unique space-based platform to test new radio communication techniques and protocols. Since being installed on the ISS in 2012, more than 2,600 hours of experiments have been conducted testing a total of 149 individual communication protocols. Some of the early results of these real-world tests have already been used to determine the types of communications technologies that can be utilized across NASA’s wide range of missions. In the future, spacecraft employing SDR radios will be able to be reconfigured with the latest and most efficient technologies that will allow them to adapt to disruptions and to more effectively share the same spectrum.
The results of this research have and will continue to benefit agencies across the federal government and the private sector as all spectrum users learn to adapt to rising demand for this finite resource.