Main Engine Cut Off

While I admittedly go out on a limb here, this idea does not come out of the blue. China and Russia have been busy practising such berthings and (very) close approaches in space with dedicated satellites disguised as space debris the past 10 years, which has the US military worried. Is the technology demonstrated by USA 276 perhaps meant to test whether such events can be observed (either optically, with radar, lidar, or whatever technology) from close by, to determine in detail what is going on?

It would be incredible (and politically sensitive) to use the International Space Station as a test subject in this way, which is why I and others are hesitant to accept this idea.

On the other hand, the ISS is there and you get frequent dockings and berthings of DRAGON's, PROGRESS, SOYUZ and HTV to watch for free, objects you don't have to launch yourself (saving development and launch costs and time. Launching a bunch of satellites for this purpose also atttracts attention, as the story with the Russian satellites shows).

So, let that sink in: Ball Aerospace, the company that built USA 276, a spacecraft that appears to be secretly moving towards a  series of clandestine very close approaches to the ISS, also built RAVEN, an experiment installed on the ISS to monitor close approaching spacecraft.