By Jonny Lupsha, News Writer

A Dutch skywatcher has photographed the X-37B military spacecraft, according to Space.com. Little is currently known about the vehicle or its top-secret missions in outer space. The sighting has inspired a review of other satellites of importance.

Ralf Vandebergh captured images of the X-37B on both June 30 and July 2, the space.com article said. The spacecraft is said to resemble a miniature version of the familiar Space Shuttle and is also called the Orbital Test Vehicle (OTV), though its missions remain secret and a matter of some debate. With such ambiguous and open-ended purpose, the OTV invites a look back at other revolutionary satellite tech already in use.

Communications Satellites and Their Roles Today

One of the most vital groups of satellites in orbit today are communications satellites. “Communications satellites provide television, telephone, and data services between two widely distant locations,” said Dr. W. Bernard Carlson, a professor in the Department of Engineering and Society at the University of Virginia. “They operate within a system in which signals are transmitted using microwaves from an Earth-based station up to the satellite, and that’s known as the uplink. The satellite, then, amplifies the signals and retransmits them to a receiving station located at another point down on Earth, and that’s called the downlink.”

Dr. Carlson said that most satellites are in a “geostationary” orbit about 22,000 miles above Earth. Their orbit is referred to as geostationary because their period of orbit is the same as Earth’s, so they stay in a relatively stationary position above us. “However, there are some satellites that operate in ‘low earth orbit,’ and those are typically about 250 miles above the Earth’s surface, and they circle the planet every 90 minutes,” he said. “The idea of using satellites to relay radio signals around the world was first proposed by science fiction writer Arthur C. Clarke in 1945. Clarke thought that satellites in geostationary orbit could be used to transmit messages from station to station and to, hence, expand radio broadcasting.” This incredible innovation in global communications came to fruition during the so-called “Space Race” between the United States and Russia in the late 1950s and 1960s and has helped frame everything from Global Positioning System (GPS) to cell phone coverage.

The Cell Phone Boom

Nowadays, cell phone use and satellites are synonymous. However, younger smartphone users may not consider that there was a time when cell phones were a brand-new use of orbiting satellites.

“The first cellular telephone network was established in Japan in 1979, and a second early system was deployed in Scandinavia—in Denmark, Finland, Sweden, and Norway—in 1981,” Dr. Carlson said. “Equally, the Japanese and Scandinavian governments could invest in this technology early on because, unlike the United States, the telecommunications in those countries is state controlled. The first network in the United States was set up by AT&T and Motorola in 1983 to serve the Chicago area—this network grew from 200,000 subscribers in the first year to two million users five years later.”

Dr. Carlson explained that the first generation of cell networks not only required a large bandwidth due to relying on analog signal processing, but they were also unencrypted, which meant that people could hack into the cell networks and easily make free calls or eavesdrop on calls using a police scanner. “In response, telecommunications engineers developed a second generation—2G—a new protocol that utilized digital signal processing,” he said. 2G introduced some commonly known elements of cell phone use like text messaging, SIM cards, and an increase in smaller and more lightweight phones that used lithium-ion batteries. The rest is history.

The X-37B (or OTV) orbiting Earth may be shrouded in secrecy, but technically, it’s in good company. Communications satellites have been a part of space for more than 50 years and have revolutionized television and telephone use in a relatively short amount of time. One day, the X-37B’s functions may look quaint or primitive by comparison to its successors.

Dr. W. Bernard Carlson contributed to this article. Dr. Carlson is a professor in the Department of Engineering and Society at the University of Virginia, where he directs the Engineering Business Program. He earned his A.B. from College of the Holy Cross and his M.A. and Ph.D. in the History and Sociology of Science from the University of Pennsylvania.