An often cited example of the importance of getting units correct in design calculations is the Mars Climate Orbiter. The orbiter got too close to the planet, causing it to pass through the upper atmosphere and disintegrate. The problem was that computer software produced an output in non-SI units of pound-seconds (lbf×s) instead of the metric units of newton-seconds (N×s) specified in the contract between NASA and Lockheed.
In future missions problems with units have been addressed. Imagine attempting to perform a fully automated landing on Mars when the software is using miles instead of kilometers. How would this impact the final result?
Mathcad is a tool to arrange, calculate, and visualize engineering calculations and units can be a part of each number or equation. Use the following worksheet to step through example problems related to using units effectively in a Mathcad worksheet.
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