3 Questions with Badri Younes

Earlier this year, NASA announced it was preparing to hand off to the private sector much of the work of communicating with spacecraft in Earth and lunar orbit. To find out a little more about the transition, Photonics Spectra spoke with Badri Younes, NASA’s deputy associate administrator and program manager for Space Communications and Navigation (SCaN). Younes is responsible for all NASA telecommunications and navigation projects and networks, including NASA’s Space Network (SN), Near Earth Network (NEN), and Deep Space Network (DSN).

What does NASA’s spacecraft communications system comprise? In other words, what are the general components, what are the overarching technologies, and — broadly — how do they work?

There are four basic sections or subsystems within a spacecraft (s/c) communications system: 1) antenna, 2) amplifier, 3) radio, and 4) data handling. For example, to send information from the s/c to a ground antenna on Earth, first the s/c data-handling subsystem, which is basically a computer, collects and carefully sequences information such as video, voice, or instrumentation measurements. Next, the s/c radio or transmitter converts that sequenced information into a modulated signal at a specific radio frequency. Then, the s/c amplifier increases the power of that signal sufficient to be received. Finally, the s/c antenna directs the amplified signal toward the ground communications system, or telemetry ground antenna. The ground communications system basically reverses the process: antenna, amplifier, receiver, data handling.

Figure 1. The Space Network was established in the early 1980s to replace NASA’s worldwide network of ground tracking stations. The second Tracking and Data Relay Satellite (TDRS) Ground Terminal (STGT) in White Sands, N.M., communicates with a fleet of satellites in geosynchronous orbit that relays information from missions to low Earth orbit. Courtesy of NASA.

NASA is investing in optical communications technology to foster the next step beyond our current microwave systems. Optical communications technology relies on optics in place of an antenna to focus electromagnetic radiation. U.S. industry has commercialized “integrated photonics” to allow many electro-optical components, even glass fibers, to be squeezed down into extremely small components. For NASA, this means that by leveraging commercially available technology, optical systems for communications and sensors can be reduced in size, mass, and cost by more than 100×. Of course, some customization may be required for the space environment. Optical communications technology will allow NASA to deliver hundreds of Mb/s from Mars back to Earth, or 100-plus Gb/s from near-Earth spacecraft.

When did NASA begin its space communications program, and what were some of the milestone achievements along the way?

NASA was formed in 1958 and its first space communications and tracking network was called Minitrack. A spacecraft’s communications system also tracks its location in space. Other significant milestones include: building the worldwide Satellite Tracking and Data Acquisition Network (STADAN) for Mercury, Gemini, and Apollo missions; building the large 64-m Deep Space Network (DSN) antennas for Mariner and Viking missions; and the launch of the first Tracking and Data Relay Satellite (TDRS) for the Space Shuttle Program in 1983. In 2013, NASA demonstrated a 622-Mb/s optical communications link between the moon and Earth on the LADEE or Lunar Atmosphere and Dust Environment Explorer mission. NASA, in partnership with MIT Lincoln Laboratory, is now developing the Terabyte Infrared Delivery (TBIRD) demonstration. TBIRD will showcase a 100-plus Gb/s optical communications link from low Earth orbit to a small optical ground terminal.

Figure 2. The three Deep Space Network sites are spaced equidistant from each other — approximately 120° apart in longitude — around Earth. As Earth turns, the facilities in Goldstone, Calif.; Madrid; and Canberra, Australia are able to communicate and listen to the whispers from the 30-plus missions within our solar system and beyond. Each facility has a 70-m (230-ft) antenna and a few 34-m (85-ft) antennas (left). Courtesy of NASA.

What are the primary reasons for deciding to hand this over to industry, and why is industry better suited to manage it? Will NASA partner with industry, or will it be 100% industry managed?

The rapid growth of the space industry offers NASA the opportunity to transition aggressively to commercially provided communications services for our low-Earth-orbit (LEO) missions. This market expansion, and the technological maturity of the vendor base, will allow NASA to become one of many customers for these services.

Most of our LEO missions that rely on communication directly from the spacecraft to the ground are already halfway there; approximately 50% of the service that these direct-to-Earth (DTE) missions receive comes from commercial contractors. The remaining 50% is provided by government-owned-and-operated assets. NASA plans for commercial entities to meet close to 100% of its DTE mission needs by 2023.

A greater challenge lies ahead for commercial space-relay communications service to LEO missions. Since this protocol is more technically complex, NASA will have contractors prove their reliability through a series of demonstration tests. The agency’s communications services program will leverage public-private partnership to fund these demonstrations, with the goal of establishing commercial space-relay service to LEO missions by the late 2020s.

Figure 3. Comprising NASA-owned and commercial tracking stations, the Near Earth Network is located throughout the world. Network assets owned by NASA are located at the Wallops Flight Facility in Virginia, the McMurdo Ground Station in Antarctica, the White Sands Complex in New Mexico, and the University of Alaska Fairbanks. (The station shown below, while owned by NASA, is operated by the University of Alaska Fairbanks.) Courtesy of NASA.

Although NASA’s first phase of commercialization will focus on microwave services, as optical communications technology matures, NASA will look to incorporate commercially provided optical capacity into our networks. Further, NASA will explore commercial communications and navigation support for our Artemis lunar missions. We welcome this transition so NASA can focus on what it does best: pushing the boundaries of exploration and what is possible in space.