SpaceSUITE: SatCom Quiz

What is the primary function of satellite communications?

• To relay and amplify radio telecommunication signals

• To observe celestial bodies

• To transport astronauts

Answer explanation

The primary function of a communications satellite is to relay and amplify radio telecommunication signals, enabling effective communication over long distances.

A satellite constellation is a group of artificial satellites working together as a system. Which of these is a communication satellite constellation, as opposed to navigation satellite constellations?

• GPS

• GLONASS

• IRIDIUM

Answer explanation

Unlike a single satellite, a constellation can provide permanent global or near-global coverage, such that at any time everywhere on Earth at least one satellite is visible. Examples of satellite constellations include the Global Positioning System (GPS), Galileo and GLONASS constellations for navigation and geodesy in MEO; the Iridium and Globalstar satellite telephony services in LEO.

Identify this famous sci-fi author who is often credited with the first practical concept of satellite communication.

• Arthur C. Clarke

• Mikhail Tikhonravov

• Konstantin Tsiolkovsky

Answer explanation

As a 27-year-old Royal Air Force officer, Arthur C. Clarke presented the concept in a paper titled “Extra-Terrestrial Relays: Can Rocket Stations Give World-wide Radio Coverage?” published in 1945. He would later become an accomplished science fiction writer. He proposed that a satellite at an altitude of 35,786 km (22,236 miles) above Earth’s surface would be moving at the same speed as Earth’s rotation. At this altitude the satellite would remain in a fixed position relative to a point on Earth. This orbit, now called a “geostationary orbit,” is ideal for satellite communications, since an antenna on the ground can be pointed to a satellite 24 hours a day without having to track its position.

What type of satellite only reflects signals without amplifying them?

• Active satellite

• Passive satellite

Answer explanation

A passive satellite only reflects signals without amplifying them. Active satellites, on the other hand, amplify the received signal before retransmitting it to the receiver on the ground. Passive satellites were the first communications satellites, but are little used now.

Launched by the Soviet Union in 1957, which is the earth's first artificial satellite?

• Sputnik 1

• Echo 1

• Telstar

• Syncom 3

Answer explanation

The first artificial Earth satellite was Sputnik 1, launched by the Soviet Union on October 4, 1957. It marked the beginning of the space age and the U.S.-Soviet space race.

What is the main advantage of geostationary satellites?

• They are cheaper to launch

• They are used for military applications

• They provide continuous coverage without tracking

• They can operate in any orbit

Answer explanation

The main advantage of geostationary satellites is that they provide continuous coverage without tracking, as they remain fixed over one point on the Earth's surface, making them ideal for communication and weather monitoring.

Name this 2013 Oscar winning sci-fi thriller that deals with the aftermath of a destroyed communications satellite.

Answer explanation

The movie won several awards, including 7 Oscars. It starred Sandra Bullock and George Clooney as American astronauts who attempt to return to Earth after their space shuttle is destroyed (in orbit) due to space debris from a communications satellite.

Which of the following is a characteristic of Low Earth Orbit (LEO) satellites?

• They are always stationary relative to the Earth

• They require fewer satellites for continuous coverage

• They orbit at altitudes of 160 to 2,000 kilometers

• They are primarily used for military communications

Answer explanation

Low Earth Orbit (LEO) satellites typically orbit at altitudes between 160 to 2,000 kilometers. This characteristic distinguishes them from geostationary satellites, which are much higher and appear stationary relative to the Earth. There's also Medium Earth Orbit (MEO), with an altitude above a low Earth orbit (LEO) and below a geostationary/high Earth orbit (HEO) – between 2,000 and 35,786 km.

Launched in 1958, which satellite was the first to actively relay communications?

• Project SCORE

• Echo 1

• Telstar

Answer explanation

The first satellite purpose-built to actively relay communications was Project SCORE, led by Advanced Research Projects Agency (ARPA) and in 1958. It used a tape recorder to carry a stored voice message, as well as to receive, store, and retransmit messages. It was used to send a Christmas greeting to the world from U.S. President Dwight D. Eisenhower.

What is the purpose of frequency allocation for satellite systems?

• To improve satellite visibility

• To enhance satellite durability

• To minimize signal interference

• To increase satellite speed

Answer explanation

The purpose of frequency allocation for satellite systems is to minimize signal interference. By assigning specific frequency bands to different satellites, it ensures that signals do not overlap, leading to clearer communication.