Engineers design instruments to measure energy across the electromagnetic spectrum. This energy travels in waves and these waves behave in predictable ways. They can be reflected, absorbed, scattered, and transmitted. Instruments measure how these waves behave when they interact with matter such as the Earth's surface or particles in the atmosphere. Scientists use this information to answer questions about the physical and chemical composition of our planet.
Some instruments are passive in that they sense energy emitted from the Earth's surface or solar energy reflected off the surface of the Earth. Mappers, or imaging instruments, measure light reflecting off the surface of the Earth to create images somewhat like an image from a digital camera. Sounders measure the vertical structure of the atmosphere either by observing the edge of the atmosphere (limb) or measuring the absorption of radiation vertically. These passive instruments use spectrometers to break apart and measure multiple bands of the spectrum like a prism, or use radiometers with filters to measure a specific band of energy.
Other instruments actively send infrared light or microwave pulses toward the Earth surface. Scientists can determine the heights of features on the Earth's surface such as mountains, sea level, and ice sheets by measuring the amount of time it takes for the signal to return. Scientists can also learn about the composition of the atmosphere by measuring how that signal interacts with the atmosphere as it returns to the instrument. Lidar and Radar are examples of active instruments.
Just as you can use data from a thermometer, barometer, and a hygrometer to get a clearer picture of the weather outside, scientists use a variety of instruments to get the bigger picture of our Earth system. Since one satellite can only carry a few of these instruments each, multiple satellites are used to collect data over the entire globe every day.
In 2004, NASA launched the Aura satellite to study the chemistry of the Earth's atmosphere. The instruments onboard Aura are helping scientists study air quality, the changing size of the ozone hole, and links between ozone chemistry and climate.
Aura is just one in a constellation of polar-orbiting satellites and together they collect data about the atmosphere, oceans, land, ice, and snow, and their influence on climate and weather. Data from these instruments are helping improve weather forecasts, manage agriculture and forests, inform fishermen and local planners, and expand our understanding how the Earth's climate is changing.
In this activity, you will select the scientific instruments for your satellite, calculate the power requirements for all the instruments and subsystems, and then construct a scale model of your very own Earth observing satellite.
Before starting this activity, you will need to assemble a variety of materials that could be found at a local craft store and education supply store.
Construct the instruments by attaching beads, buttons, sequins, and drink stirs to the cubes using Glue Dots (see photo below). The communications and data handling subsystems each require an antenna (short drink stir with sequin).
Use the information on the worksheet to calculate to required solar array size and number of batteries. The cardboard will serve as the satellite bus - the platform to which all the subsystems are attached. Construct the satellite by connecting all the cubes and attaching to the cardboard with glue dots. Finally, tape the solar panels to drink stirs and connect to any cube.
Weigh your satellite. If your satellite weighs between 18 and 25 grams, congratulations! Your satellite is ready to launch!
Name your satellite and describe how data from your instruments will help benefit society