These Satellites Just Nailed the Most Precise Formation Flight in Space History

The European Space Agency’s Proba-3 mission has achieved something no other mission—or synchronized swimmer—has before: autonomous, precision formation flying in space with millimeter accuracy. ESA’s Proba-3 satellites—the Occulter and the Coronagraph, respectively—maintained a steady 492-foot (150-meter) distance from one another in a highly elliptical orbit, simulating a single massive instrument. The same principle is used by satellite constellations and planned space telescopes to capitalize on the laws of physics and the relatively noiseless environment of space to collect more data than otherwise possible. But Proba-3’s goal is unique: to align the spacecraft in such a way that one (the Occulter) can block out the Sun’s glare, while the other (the Coronagraph) can take a clean look at its wispy outer atmosphere—the solar corona. For this to work, the two spacecraft can’t just drift around together—they must stay aligned with millimeter-level (0.04-inch) precision, with no micro ... Read full article.