What am I checking out? Radiant doesn't appear to actually be anything or do anything. That page appears to be a vague description of a thing that purports to provide access to data but doesn't actually provide any information on how to get it.
I don't know where the project stands at present, so I dont have an objective measure to discriminate between what they claim to be doing and what they're actually doing.
Coincidentally, I had a meeting in DC today at the Omidyar Network and Radiant was mentioned briefly in the context of providing startups with a way to bootstrap without spending large chunks of money on acquiring geospatial data.
[1] http://www.reuters.com/article/us-technology-satellites-huma...
[2] https://www.independent.co.uk/news/science/bill-gates-melind...