MMS Observatory #1 (bottom) and #2 (top) are shown here in their "mini-stack" configuration for shock testing, which helps determine if they are capable of withstanding the rigors of launch. The gold ring seen between them is one of three that will be used when all four spacecraft are stacked in the fairing for launch. Once in orbit, the separation systems will fire, releasing them into the pyramid formation necessary for the mission.
NASA/GSFC
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