SGCN is different from CORN, in that it is a network of geodetic control points - large, precisely surveyed points. CORN did not need precisely surveyed points since the targets were mobile. There is mention of the SGCN inside the HEXAGON Mapping Camera history with Mission 1216... which is a long time after the construction of this cross field (1966). Mention of SGCN is within two NRO docs as assisting with MC&G, but also an Airman magazine, and an unclassified publication along with a few Defense Mapping Agency papers. If SGCN was supposed to be "born secret," it too suffered from bad OPSEC. But I'll publish whatever I find out about it in TSR.

The NRO and NGA have "washed" their hands of older imagery and handed it off to the USGS and National Archives. If you go to the USGS archive of declassified satellite imagery (https://earthexplorer.usgs.gov/), you can request declassified images from CORONA, ARGON, LANYARD, GAMBIT, and HEXAGON missions. If you use the coordinates provided by the Google Earth maps, you can get plenty of imagery of the Arizona desert... as well as many other places across the globe. The inclusion of Casa Grande within the collection does not prove that they were satellite targets... nor does it disprove it either. But many of the suppositions made about the targets' CORONA connection (e.g. blurry imagery, discovering North-South orientation of the imagery) are not supported by some of the angles of the imagery swaths.

But all I can say is - go look at the USGS imagery, see if you can find the range, and make your own determination. Remember this though - for all of the previously "TOP SECRET" material declassified about CORONA, GAMBIT, and HEXAGON (**thousands** of pages of material) in both CIA and NRO databases, there was ZERO mention of this range, or its unique targets. The NRP's chosen route to determine satellite calibration - the Controlled Range Network - has no listing of a 50-foot Maltese Cross target within the 1965 CORN Manual, 1966 CORN Manual, or the '73/'74 CORN Proposal (all are declassified on NRO's "FOIA For All" website so you can judge for yourself).

I've got FOIAs out with the US Geologic Survey (for mapping), the Dept of Commerce/NOAA/National Geodetic Survey (geodetic survey markers), and the NGA (for mention of this range and another). I will disseminate these to the TSR audience once they are completed.

Yes, the Hexagon Mapping Camera history document is a well-written introduction to the NRP as a whole, as well as mapping, charting, and geodesy (MC&G). Funny enough, the document does list the target range of ground control targets used by Hexagon - the BAR XC range that was present in "most of Arizona, and part of New Mexico" (over 90,000 square mile range). Comparing the size of BAR XC compared to Casa Grande, there seems to be additional evidence that no NRP systems precipitated the use of the concrete crosses. I've got two FOIAs in to NGA (and NRO) about BAR XC with NRP. More in the follow-up article.

No, from all accounts that I found the range was used for testing high-altitude aerial cameras for mapping (more on the specifics of NRP mapping, cartography, and geodesy in a later article). I knew that Davis-Monthan AFB (Tucson, AZ) flew U-2s from mid-1960s through the mid-1970s, and there was no USAF-Casa Grande connection (e.g. U-2 pilots fly over for ??? practice missions) in either USAF or CIA/NRO docs.. Couldn't find any IDEALIST U-2 connection either. If there was a Program-D drone or manned aircraft connection to the range, it was not found in any NRO or CIA declassified documents.

Yes, the Air Force Satellite Test Center out of Sunnyvale performed command and control of the satellites, and "Stick" operators were, according to all accounts, *very* good at their jobs at maintaining precise orbital altitudes.

The article doesn't dispute transient, occasional, or accidental use of the optical range for satellite mapping... however, CORONA equipment and flight profiles were not designed for mapping or geodesy. ARGON (KH-5) was the Army's mapping system within the National Reconnaissance Program that did very poorly according to their own documentation. At the time Casa Grande was constructed (1966, according to the survey markers), the NRO and CIA determined their systems did not meet expected requirements for map or chart accuracies. 1965 NRO Memo is here - https://www.nro.gov/Portals/65/documents/foia/CAL....