The Rosetta spacecraft, which launched in 2004 and has been in sleep mode for nearly three years, will be turned on Monday morning.
Scientists put Rosetta into a planned hibernation 31 months ago in order to save enough power to complete its mission. That mission is to land on comet 67P Churyumov-Gerasimenko.
In June, it will launch a probe to land on the comet and collect data and pictures from the icy surface.
It will be the first time any nation will attempt to land on a comet.
You can watch Rosetta's wake-up call live online at 3am Monday CST.
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