Probe detection & response times for various approaches and altitudes, sigint for radio chatter that doesn't reach past the US, similar for active radar targeti

Probe detection & response times for various approaches and altitudes, sigint for radio chatter that doesn't reach past the US, similar for active radar targeting high altitudes, wasting more US money than they cost China by a long shot, trial-run for a mass launch of these with potentially more interesting payloads than these sacrificial trial ones are carrying (even just as a kind of attention- and resource-wasting chaff during, say, an attack on Taiwan), radio-signal mapping for some crazy new passive guidance system. Lots of possibilities.