Why do you think it was a secret to anyone? Any amateur astronomer can figure it out from mirror size and orbital parameters. A 1968 NASA publication (sold for

Why do you think it was a secret to anyone? Any amateur astronomer can figure it out from mirror size and orbital parameters. A 1968 NASA publication (sold for $3.00) discusses various limitations, concluding: "The telescope objective for best resolution, as viewed from a satellite at an altitude of 320 kilometers, requires a diameter of about 1.6 meters to resolve a 12-centimeter radius" https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690003603.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/196900... That approximately 10 cm resolution has always been a resonable guess of the capabilities of best spy satellites. Trump's tweet surprised no-one. It confirmed what has always been thought to be true.