Inside Satellites - How They Work Quiz | Sci / Tech

Quiz Answer Key and Fun Facts

1. I often explain that satellites are a lot like cars. If you can think of something in a car, chances are satellites have a similar system. Which of the following is a traditional satellite system?

Answer: Attitude Control System

The Attitude Control System is similar to a car's steering wheel. Satellites don't have air conditioning systems, but they do have Thermal control systems including heaters and radiators. Cars have gas; satellites have propellant. Cars have tires; satellites have thrusters. Cars have radios; satellites have antennas for communication.

2. Which satellite orbit is typically used by spy satellites and science mapping missions?

Answer: Polar Orbit

Polar orbits go around the Earth from pole to pole. The Earth rotates beneath this orbit, so in 12 hours the satellite can view any spot on the Earth's surface. Geostationary orbits are used by communication satellites since the satellite will stay above the same point on the Earth's equator. Low Earth orbit satellites circle the Earth in about 90 minutes.

A highly eccentric orbit is one that is shaped like a big oval. Part of the orbit is close to the Earth, but the opposite side is far from it.

3. Satellites often rely on the Sun for which of these functions?

Answer: Power

Course Sun Sensors (CSSs) are used to point the solar arrays if the satellite is in trouble. These are usually installed directly on the solar arrays. Power is generated from the solar arrays and stored in batteries for eclipse periods.

4. Most unmanned satellites are launched into space and never touched by humans again. What is the only system on a satellite that can be modified after launch without a visit from an astronaut?

Answer: Software

With the proper electronics design, the software on a satellite can be upgraded just like upgrading the software on your computer.

5. Why do satellite engineers wear white coveralls ("bunny suits"), masks, boots and gloves when working near satellites?

Answer: To prevent contaminants from getting on the satellite.

Often the most hazardous substances near a satellite are people. We continually shed hair, skin and oils. An insignificant smudge can evaporate in a vacuum and redeposit on a sensitive optic, effectively ending a multi-million dollar mission.

6. What is the gold or silver colored "fabric" material that covers the outside of a satellite?

Answer: Thermal Blankets

Thermal blanketing is used to keep the satellite insulated from extreme cold or extreme heat. Without the blanketing, epoxy would melt in the heat of the sun, and liquids in the sun's shadow would freeze. As the satellite passes into and out of the sunlight, thermal expansion causes stress in structures and rapidly age the satellite. Keeping the satellite thermally stable is a critical function of the thermal blankets.

7. What is the term used to describe the information received from a satellite?

Answer: Telemetry

Telemetry is data transmitted via an antenna to a ground station. Complex algorithms are used to insure any data that is garbled in a transmission can be restored. The satellite uses a sequence of bits (1s and 0s) to allow the ground station to "lock into" the data stream and interpret the remainder of the transmission. Embedded in the data stream are codes that describe the types of data being sent: attitude control solutions, thermal sensor data, battery charge information, etc. Further complicating the transmission, some missions use encryption to insure the data cannot be used by eavesdroppers.

8. Which of the following choices is the name of the rapidly spinning disks used to keep the satellite oriented correctly?

Answer: Reaction Wheels

Reaction Wheels spin at over 1000 rpm. By changing their spin rate, the satellite reacts by rotating its orientation to conserve angular momentum. When the maneuver is complete, the wheels are returned to their original speed.

Magnetic Torquer Rods are electromagnetic rods that react against the Earth's magnetic field.

Inertial Momentum Units are sensors that provide feedback to the control software telling how much rotation the satellite has had since the last readout.

9. When operators fire the main engine on a satellite, they say they're doing a "Delta-V" maneuver. What does "Delta-V" mean?

Answer: Delta Velocity

Delta-V maneuvers are very important but typically don't generate a lot of instantaneous thrust, perhaps 20 to 100 pounds of force. Applied over the course of several minutes, this thrust can generate a lot of velocity. Thus the name "Delta-V" or "change in velocity".

10. The alignment of some parts of the satellite is very important. What piece of equipment is commonly used to measure alignment? (Hint: it's the same thing used by highway surveyors.)

Answer: Theodolite

Some parts that need to have their alignment measured have an "alignment cube" installed on it. The alignment cube is a precision glass cube with reflective sides. Each face of the cube is perpendicular to the others. The theodolite operator looks through a scope on the theodolite at the cube and notes the angle when they see their reflection in the cube.

Theodolite operators are very adept at geometry and trigonometry!

Source: Author ahrzee

This quiz was reviewed by FunTrivia editor crisw before going online.
Any errors found in FunTrivia content are routinely corrected through our feedback system.

Inside Satellites - How They Work Quiz

We rely on satellites every day to relay our messages, to keep us safe and to tell us where we are. But do you know how they're built and how they work? Here are 10 multiple choice questions that will help you appreciate this sky-high technology.

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