There is substantial public documentation of the extensive system of calibration targets that were built for CORONA and subsequent satellite programs, such that it's hard to imagine why so much confusion seems to exist in this area. In fact Arizona was used for both, but satellite imaging calibration targets of various types are found in California and throughout the country. The most extensive system of photogrammetric calibration targets in the US is at Edwards AFB, where features include 10 mile reference rulers. Smaller references were sometimes just painted on the tarmac at air force bases for simplicity.
That said, these kinds of things are, necessarily, obvious and accessible to anyone. Calibration targets built for various programs are sometimes used for other programs, sometimes even by rival nations, simply because they're known to be there and it's easier to use something in place than to build something new. The fact that nearly all of these programs operated under great secrecy and before retention of classified records was typical (there were not yet as extensive of records retention mandates applicable to classified programs) means that the details can now be somewhat obscure, just because all of the original documentation was destroyed or lost after the program closed.
An interesting variety of calibration targets are those intended for radar (SAR) use, since they take the form of 3D shapes rather than 2D images. Since SAR is a much more recent technical development in remote sensing there are far fewer public details, but various military and contractor installations have included, at times, oddly carefully sculpted gravel piles that are assumed to serve this purpose. An example is at the former Lockheed site in Potrero Canyon near Beaumont, CA.
Many of the images covering the US taken by CORONA and several subsequent programs, mostly for calibration or testing but sometimes by error, were declassified under Clinton-era rules and given to the USGS. You can now browse them as part of USGS's general aerial imagery collection. The resolution is insufficient for most modern uses (the USGS's collection of agricultural aerial survey photos is far more useful), but they're unrivaled in the sheer land area they cover in one large frame.
None of this is really that surprising. DataFoundry is a real company and pretty typical for the industry, I don't see any particular reason to suspect that they're a front. They're on the small side for the datacenter/colo sector but similar to something like PheonixNAP. While I can't say I know any of their customers personally I have gotten quotes from them in the past which were competitive but not quite the best available.
No particular technical expertise is involved in running these sorts of companies, those staff are hired. The top-level executive management is more reminiscent of commercial real estate than anything technical---it's buying land, building buildings, and putting tenants in them.
That the owners of the company have been involved in Usenet and VPN services is quite unsurprising---these are both industries that are technically simple, easy to get into, and can show a pretty quick profit. The up-front capital involved to get into them is having rack space and connectivity... things that, as owners of a colo outfit, they already had on hand. VPN services also have a high degree of customer overlap and can share infrastructure with usenet, so there is a VERY high degree of overlap between usenet providers and VPN providers---to the extent that it's more suspicious if a Usenet provider doesn't share owners with a VPN provider.
This is a throwaway account as I will be mentioning some slightly sensitive personal details.
I do not currently work in law enforcement or intelligence, but for various reasons from some years ago to the present I have been a member of one of the fusion-center-type communities which Netsential hosts. A small amount of my personal information is included in the breach as a result, but of course, this is far from the first time that's happened to me.
I think you have somewhat of a misunderstanding about Netsential's service offerings. While they do provide physical hosting, that is not their primary product, they are not used for "managing the physical servers (think Dell blade computers for instance) that these websites ran on top of" as you say in the blog post. This is only incidental. Their primary product is the software, which is not very good from either a code quality or user experience perspective, but is reasonably unique in its capabilities. They offer a completely "turnkey" solution, including for example a telephone technical support/customer service line for users of the portals that they staff and handles routine things like password resets.
They're not a hosting company, they are primarily a SaaS operation that also does some custom software development.
So it's not at all true that there's no reason to use them over a cheaper service like Azure. These organizations would need to hire some other company to develop the software if they did that, and that would end up costing them more because they'd be looking at a semi-custom project (COTS CMS solutions would partially meet the needs) rather than "just another license" with Netsential.
That said, these kinds of things are, necessarily, obvious and accessible to anyone. Calibration targets built for various programs are sometimes used for other programs, sometimes even by rival nations, simply because they're known to be there and it's easier to use something in place than to build something new. The fact that nearly all of these programs operated under great secrecy and before retention of classified records was typical (there were not yet as extensive of records retention mandates applicable to classified programs) means that the details can now be somewhat obscure, just because all of the original documentation was destroyed or lost after the program closed.
An interesting variety of calibration targets are those intended for radar (SAR) use, since they take the form of 3D shapes rather than 2D images. Since SAR is a much more recent technical development in remote sensing there are far fewer public details, but various military and contractor installations have included, at times, oddly carefully sculpted gravel piles that are assumed to serve this purpose. An example is at the former Lockheed site in Potrero Canyon near Beaumont, CA.
Many of the images covering the US taken by CORONA and several subsequent programs, mostly for calibration or testing but sometimes by error, were declassified under Clinton-era rules and given to the USGS. You can now browse them as part of USGS's general aerial imagery collection. The resolution is insufficient for most modern uses (the USGS's collection of agricultural aerial survey photos is far more useful), but they're unrivaled in the sheer land area they cover in one large frame.