Building a new Radar Altimeter Model

by Estela Hernandez

The radar altimeter measures the altitude of an aircraft by measuring the echo of a radio wave to return and the direction from which it returns. The radar altimeter provides an accurate indication of altitude of the Space Shuttle from 5,000 ft. to touchdown. We are trying to update the Space Shuttle model to make the radar altimeter more accurate. Currently, I am looking at the math model and trying to compare it to our Space Shuttle simulation. This is being done at the same time as the implementation of global positioning system (GPS). Eventually, with both of these instruments working accurately the astronauts will have more precise information.

The math required for the implementation of the model is basic calculus and physics. This is how the model simulates the changes in altitude.

The scientists are NASA employees as well as contractors from Houston and Los Angeles. The scientists design and check the model. Then they send us the model with their checks so we can match them with ours. This will allow us to make sure that it is accurately modeled. This simulation will take place in February when the astronauts will fly the new radar altimeter model at the Vertical Motion Simulator. The astronauts will fly approach and land usually starting at about 10,000 ft. As a simulation engineer, one of my responsibilities is to fly the simulator to make sure everything is working properly.

While the project is challenging it is also very interesting. If I run into problems, there is always someone who I can turn to for help.