Engineering
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LRO being lowered by crane into the enormous Space Environment Simulator at Goddard Space Flight Center. The simulator can test the spacecraft in extreme temperatures and under vacuum. (NASA) |
A scientific instrument like CRaTER has to detect incredibly small particles. It has to survive a shaky rocket launch. It has to work in a vacuum where the temperatures range from extremely cold to extremely hot. We had to make sure CRaTER would do its job at the Moon.
First, we tested whether CRaTER could detect cosmic rays. To do this, we took the instrument to particle accelerators. These are machines that make protons and other particles travel at almost the speed of light. Basically, particle accelerators create artificial cosmic rays. CRaTER’s data looked good, so we knew it would detect real cosmic rays in space.
We also tested whether CRaTER could work in a vacuum. On Earth, the air can help cool electronics through conduction (touching the electronics) and convection (blowing by the electronics). In a vacuum, there is no air, so electronics can overheat. We put CRaTER in a vacuum chamber and pumped the air out of the chamber. Fortunately CRaTER worked.
Next, we had to make sure that CRaTER would survive the shaking that occurs during a rocket launch. To test this, we put CRaTER on a machine called a shake table. This table shakes the instrument very hard, just like a rocket would. Nothing broke, so we knew that CRaTER could survive the launch.
Finally, we had to test the whole LRO spacecraft with all its instruments. It went through its own shake tests. The entire spacecraft was also put in a vacuum chamber the size of a tiny house. This chamber can heat up and cool down the spacecraft from -180 to 150 °C (-300 to 300 °F). The spacecraft alternately froze and cooked in the vacuum chamber for almost two months!
After more than half a year of rigorous testing, everyone knew that CRaTER and LRO were ready to go to the Moon.
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“Wow, that’s more testing than I get during the school year! Oh, wait… I’m a cosmic ray, so I don’t go to school. But astronauts do go to space. Go to the Future section to discover how NASA astronauts plan to explore outer space.” |