An American space launch is a very high-security affair. Systems are locked down, many of the staff hold national security clearance, and the rocket and its payload are carefully protected, for obvious reasons.
So, it was a little unusual when SpaceX launched its CRS-28 resupply mission to the International Space Station back in June, because it contained a special satellite that the US military was actually encouraging people to hack.
Named Moonlighter, the diminutive 34 x 11 x 11cm